Copper Casting In America (Trevelyan)
Martyn Harrison wrote:
I'm fascinated by the "meteoric copper" idea. I'm ok with the notion that elements up to Iron are formed by gradual fusion processes inside stars. But as far as I know, that's where these fusion processes stop. Copper isn't formed in that way. So I can't see how a lump of space debris could reasonably be copper. It could reasonably include a *bit* of copper, but not easily *be* a copper lump. Iron yes, you certainly get lumps of iron when, e.g. a supernova goes whomp, but copper, no I don't see how that's going to happen. So I find it enormously unlikely that a lump made predominantly of copper might end up as a meteor. Does anyone know if there is any credibility in this claim in practice? Martyn, In this case, the term 'meteoric' doesn't mean 'from meteors', as it does when it's used in the phrase 'meteoric iron'. At least as it's used in archaeology. Eric explained it, and could do better than me; but I recall it means that the copper was precipitated out of solution that was forced closer to the surface into igneous, and IIRC sedimentary, formations. As I understand it, all the elements beyond iron are formed via supernovae. So, in that sense, yes; the copper we're discussing did come from elsewhere in space. Tom McDonald Apparently on date Sat, 03 Jul 2004 10:44:05 +1200, Eric Stevens said: On Fri, 02 Jul 2004 06:02:01 GMT, Seppo Renfors wrote: Gary Coffman wrote: On Thu, 01 Jul 2004 08:26:52 GMT, Seppo Renfors wrote: Gary Coffman wrote: On Tue, 29 Jun 2004 05:48:01 GMT, Seppo Renfors wrote: Gary Coffman wrote: [..] Again, porosity is the problem, and that should show up on radiographs, as it does for R666 (which certainly shows evidence of being melted in atmosphere, though not necessarily evidence of being cast), but none of the other artifacts presented show that sort of porosity. See: http://www.iwaynet.net/~wdc/copper.htm The 4th and 5th pictures down. Those pictures do not show any evidence of the characteristic porosity copper casting would produce. They disagree with you as it states "The casting bubble can clearly been seen...." And as I note below, they are quite wrong. It is rather obvious that they have little practical experience or knowledge about working native copper. It behaves significantly differently from other metals when melted or cast. Copper is copper no matter what part of the world it is in. ALLOYS vary from place to place. So I find it hard to accept Michigan "native copper" is much different from that here in Australia. Michigan native copper is 'meteoric' copper. Australia does have some meteoric copper (see http://www.econs.ecel.uwa.edu.au/AMH...ett/news21.htm) but it is accessible in quantitities very much smaller than in NA. I would also direct your attention to this: http://people.uncw.edu/simmonss/P6030052.JPG There is little question this has been melted - and where are the obvious faults? Your authorities are a dentist, an engineer whose expertise is with iron and steel, and one chemist (who disagrees with 4 others at his school). Frankly, not a very impressive collection of authorities on the metallurgy of native copper. If you go to purchase a bottle of wine, which is the most important - the label on the bottle or the taste of the content? The above is pointing to the label, ignoring the content. The single large surface bubble is a blister, common when the surface of a wrought piece is overheated. Compare it to the radiograph of R666. The latter does show the characteristic deep pattern of porosity of an at least partially melted copper object. [..] Eric Stevens |
Copper Casting In America (Trevelyan)
"Paul K. Dickman" wrote: In order to illustrate the nature of the porosity in melted copper I put a few pictures up. http://tinyurl.com/3cw7p Very interesting! The first labeled Casting is a small ingot cast of ca110 copper It started out essentially 99.9% fine. The casting method was about as simple as you can get. It was melted with an oxy-acetylene torch and poured into an open mold, made by scraping a depression into some foundry sand. The "cocks comb" sticking out in the upper left is not a sprue. When the pour was finished the ingot was shaped like a little loaf. As it solidified, dissolved gasses came out of solution with the metal. As they did they were trapped by the solidified metal on the outside of the ingot and built up pressure. Eventually a weaker spot in the surface of the metal gave way and metal and gas squirted out. Like stepping on a ketchup packet in the McDonalds parking lot. I can't say I can speak from experience on that issue :-) The size of this is indicative of how much gas was dissolved in the metal. It is approximately 10% of the original volume of the ingot. Essentially what you are saying is that a lot of the gases escaped before it solidified. The rough area in the lower left is not indicative of porosity, It is where the metal first struck the sand. When it did, it's surface tension was sufficiently disturbed to allow it to flow into the spaces between the sand grains. The second picture, labeled section, shows what this looked in a cross section cut at about the base of the "cocks comb" You can easily see the large bubbles. It also has a large amount of small bubbles that are visible under a 10 power loupe. You can see that it looks very similar to the R666 radiograph. However that piece looks more like a mistake than a deliberate casting. ....or just a casting to make small pieces into one big piece? You can also see that it is not a single round bubble but a miriad of amorphous blobs. ....still similar to R666.... The third picture, labeled forgings, shows it's workability. The lower shot is from the pure copper ingot, You can see it is full of fractures and tears. I assume this is from the melted copper described above? Are you suggesting the "tears" are the result of (A) the pure copper having been melted (B) because it is pure copper? If (A) how does it compare to not melted copper of equal grade? Would it not also depend on the handling of the material if it tears or not - eg more frequent annealing - hot working etc? If it is from the melted ingot - what has happened to the "myriad of amorphous blobs" - they are no longer visible. The upper forging is made from an ingot cast from approx. 4% silver-96% copper. This ingot exhibited no cocks comb and the forging was made from the entire ingot, with no waste removed. The two metals are visually identical, but one casts like crap and the other doesn't. If something is acceptable or not, depends on the use and views of acceptability on the day. If something was melted to get a single lump, to be later beaten into a sheet for further working to jewellery for instance, then perhaps it really doesn't matter - perhaps it may no longer even be obvious to have been cast. If they were casting on any scale, it is not just inevitable that alloying occurs, it is pretty much a necessity. I doubt there was any real high volume of casting occurring, considering other sources. However the lack of scraps and off cuts note, as well as the storing of off cuts in a bag with other copper artefacts and a sheet of copper indicates scraps were used up. If you want to prove casting, stop stroking around with radiographs and look for alloying. Well..... there is the problem. This information hasn't been gathered of either kind to any extent to my knowledge. The radiography (or analysis) of two items... or even a dozen items, is not representative of the tens of thousands of artefacts found. -- SIR - Philosopher unauthorised ----------------------------------------------------------------- The one who is educated from the wrong books is not educated, he is misled. ----------------------------------------------------------------- |
Copper Casting In America (Trevelyan)
Philip Deitiker wrote: Eric Stevens says in : These words are unambiguous and do not depend solely on the interpretation of the information posted on Connor's site. This is not so hard to see, copper comals made in Guerrero and Xoahaca are made in much the same way they were previous, the comal being the primary 'tool' made in the region. These comals are not cast, they are pounded. Alright, I have to ask - what the hell is a "comal" (it aint English!)??? I know of a "Comal River" associated with "Guerrero", there is "Comal County", there is a town in Mexico called "Comal"... there is something "El Comal" that appears to refer to "great home-cooking from Michoacan, Guerrero, Jalisco, and Oaxaca, prepared by Luz Herrera Ibarra, a biology teacher from Acapulco." It appears to be a utensil/cover plate of some type, but ... but.... "The "comal" used during the Epi-classic was made of clay. The modern "comal" is a large round cast iron plate placed over a heat source." Not copper by the look of it and indeed cast!! [..] -- SIR - Philosopher unauthorised ----------------------------------------------------------------- The one who is educated from the wrong books is not educated, he is misled. ----------------------------------------------------------------- |
Copper Casting In America (Trevelyan)
Paul K. Dickman wrote:
In order to illustrate the nature of the porosity in melted copper I put a few pictures up. http://tinyurl.com/3cw7p The first labeled Casting is a small ingot cast of ca110 copper It started out essentially 99.9% fine. The casting method was about as simple as you can get. It was melted with an oxy-acetylene torch and poured into an open mold, made by scraping a depression into some foundry sand. The "cocks comb" sticking out in the upper left is not a sprue. When the pour was finished the ingot was shaped like a little loaf. As it solidified, dissolved gasses came out of solution with the metal. As they did they were trapped by the solidified metal on the outside of the ingot and built up pressure. Eventually a weaker spot in the surface of the metal gave way and metal and gas squirted out. Like stepping on a ketchup packet in the McDonalds parking lot. The size of this is indicative of how much gas was dissolved in the metal. It is approximately 10% of the original volume of the ingot. The rough area in the lower left is not indicative of porosity, It is where the metal first struck the sand. When it did, it's surface tension was sufficiently disturbed to allow it to flow into the spaces between the sand grains. The second picture, labeled section, shows what this looked in a cross section cut at about the base of the "cocks comb" You can easily see the large bubbles. It also has a large amount of small bubbles that are visible under a 10 power loupe. You can see that it looks very similar to the R666 radiograph. However that piece looks more like a mistake than a deliberate casting. You can also see that it is not a single round bubble but a miriad of amorphous blobs. The third picture, labeled forgings, shows it's workability. The lower shot is from the pure copper ingot, You can see it is full of fractures and tears. The upper forging is made from an ingot cast from approx. 4% silver-96% copper. This ingot exhibited no cocks comb and the forging was made from the entire ingot, with no waste removed. The two metals are visually identical, but one casts like crap and the other doesn't. If they were casting on any scale, it is not just inevitable that alloying occurs, it is pretty much a necessity. If you want to prove casting, stop stroking around with radiographs and look for alloying. Paul K. Dickman Paul, First, wow. Thanks for taking the bull by the horns and doing an experiment. I'm reminded of the old story of the horse's teeth. While a bunch of Greek philosophers stood around trying to reason how many teeth a horse had, a Roman walked up to the horse, opened its mouth and counted them. Thanks for the 'counting'. Second, I'm stroking around as fast as I can with what I have :-). (Insert joke here.) As I learn more from people such as you and Gary, I learn what questions to ask. I'm getting to the point where I have enough information to ask intelligent questions of the literature and the folks working on the issues. I will soon be composing an email to some archaeologist in Wisconsin, at the University of Wisconsin in Madison, and at the Wisconsin Historical Society. I'll also be looking for suggestions as to who to contact in Michigan, other than Susan Martin. Any suggestions as to other questions to ask, or other folks to contact, would be appreciated. Third, wow. Tom McDonald |
Copper Casting In America (Trevelyan)
On Sat, 03 Jul 2004 00:38:46 GMT, Martyn Harrison wrote:
I'm fascinated by the "meteoric copper" idea. I'm ok with the notion that elements up to Iron are formed by gradual fusion processes inside stars. But as far as I know, that's where these fusion processes stop. Copper isn't formed in that way. So I can't see how a lump of space debris could reasonably be copper. It could reasonably include a *bit* of copper, but not easily *be* a copper lump. Iron yes, you certainly get lumps of iron when, e.g. a supernova goes whomp, but copper, no I don't see how that's going to happen. So I find it enormously unlikely that a lump made predominantly of copper might end up as a meteor. Does anyone know if there is any credibility in this claim in practice? You're being confused by Eric's use of an obscure term of art for geochemically processed copper originating in a water saturated subsurface environment. All that "meteoric copper" means in this context is that it was deposited geochemically from a mildly acidic aqueous fluid whose watery origin was surface precipitation (rain-meteorology-meteoric), rather than liberation of water of hydration in the deep rock. A more complete explanation is that rainwater percolated down through faults in volcanic rock and reacted with volcanic sulphur to form a mild sulfuric acid solution. This acid solution, raised to temperatures on the order of 350C in the basement rock (and still liquid due to the high pressure there), then dissolved copper being held in more complex oxide or sulphide form in the deep rock, producing a solution of CuSO4. Over time, geologic processes forced this copper laden solution back up towards the cooler surface regions. When iron bearing rock was encountered, the reaction CuSO4 + Fe = FeSO4 + Cu resulted. Since copper and iron sulphates are soluble in water, they are free to move about in the rock following fissures and faults. But metallic copper isn't soluble in water, so after the reaction it is left behind to form "veins" of native copper in the rock matrix. To go into excruciating detail on this process requires knowledge of physical chemistry, equilibrium solutions, and a good bit of geology to understand why it works as it does. For example, I'd expect objections from the lay person that since there is iron in the deep rock too, the geochemical refining process should have redeposited the copper there. But it doesn't, because the high temperature and pressure in the deep rock shifts the equilibrium point of the reaction in an unfavorable direction for that to occur. Higher up, where temperatures and pressures are lower, the reaction can proceed to a more favorable equilibrium with respect to copper precipitation. (There are other factors too, but I'm not going to write a geochemical treatise here.) In any event, this natural geochemical refining process means that native copper (meteoric copper) consists of veins of extremely pure crystalline copper. This is what makes native copper so desirable, it doesn't have to be smelted or further chemically refined, it merely needs to be mechanically separated from the rock through which the veins pass. Just as veins in the body come in different sizes, so too do ore veins in a rock matrix. The vein can be hair thin, or several feet in diameter, or any size in between. That means chunks of native copper come in all sizes, allowing the ancient craftsman working at a sufficiently rich site of native copper, such as Keweenaw, to choose the size of raw material appropriate for making whatever artifact he chose. Gary |
Copper Casting In America (Trevelyan)
Eric Stevens wrote:
On Fri, 02 Jul 2004 02:50:07 -0500, Tom McDonald wrote: Eric Stevens wrote: snip I haven't been able to track down Mallery's papers. As to whether or not they would be interpreted differently today - I very much doubt it. The text quoted by Mallery is most basic metallurgy. I've just emailed both the NYTL and the NIST about these reports. Probably a lost cause, but what the hell. Good idea. I was tempted to do that but never got around to it. I would be surprised if they had the relevant files after all these years. Eric, I heard back from the librarian at the NIST. He says they don't have L-C 444 anymore, but that is because it's missing, not because they don't curate them. (It turns out that L-C 445 is about painting radiators in steam heat systems :-)) He said he would contact other libraries that maintain collections of the old NBS Letter-Circulars. If he gets a copy, he will snail-mail a copy to me; if not, he'll tell me 'no joy'. Still waiting to hear from New York Testing Labs. They apparently were bought by a larger firm a few years ago, but it looks like they maintained their name. The work they did, at least on the three indicated artifacts, probably was done on contract with the National Museum of Natural History. If so, the Museum might have to consent to releasing the report, if NYTL still has it. Who did you contact about Mallery's papers? Would it help, do you think, for me to contact them as well? However, please note that the NBS report Mallery cites on page 223, Letter-Circular 444, July 13, 1935, is _not_ the source of the quotation by Dr. George P. Ellinger on page 225, quoted by you below. The quotation by Ellinger has to have been made _after_ the NYTL report; and as I note below, the NYTL testing had to have been done at least a decade after NBS L-C 444. We don't know whether Ellinger is being quoted from a report, a letter, a conversation, or what. We can't follow up on this to see whether Mallery got it right. I agree. I'm trying to use Mallery as incontestable proof of copper casting. I was merely disputing the implication that Gary Coffman had settled the matter. I never said that the matter was settled. Gary and Paul have lent us expertise I don't have, and as I learn more, I'm trying to apply it correctly to the info I have. I think that soon I'll know enough to at least ask reasonable and germane questions of the literature, and living archaeologists. Them's good fun! Important words from the quote from Mallery include: "X-RAY EXAMINATION:—The tools were radiographed using standard techniques. A review of the radiographs led to the following observations:— # I—The three tools were originally cast." "The specimens are originally cast but apparently have been reheated and worked to some extent." This was the testing done at the behest of James A. Ford of the American Museum of Natural History, per Mallery. Ford began his tenure at the Museum sometime in 1946: http://www.mnsu.edu/emuseum/informat...ord_james.html or http://makeashorterlink.com/?J567224B8 "Following this report, six leading American museums furnished tools from the United States, Canada, Mexico, Guatemala, and Peru for testing. Various metallurgists who have examined the micrographs of these tools concur in the findings of the New York Testing Laboratories, Inc. that many of the specimens examined have been cast. Dr. George P. Ellinger, metallurgist for the National Bureau of Standards, said, after examining the submitted specimens, "The presence of cuprous oxide in the interior of the tools tested and the concavity caused by shrinking justify the conclusion that the vast majority of the ancient tools were cast." Even if Mallery quoted accurately from the NYTL and George Ellinger, we are still left with the problem that neither the NYTL report, or the statement by Ellinger, state what Gary and Paul assure us would have been obvious from the radiographs; characteristic porosities. Internal small bubbles. Many. With respect to Gary, the fact that he did not know of the use of coal or carbon to deoxidise molten copper suggests that his is not the final word on the subject. Again, never said any one person would have all the pieces of the puzzle. However, Gary certainly knows more than I did; and Paul is adding more still. BTW, in another post (to Phil, I think) you said that I seemed to have not seen, or to have ignored, the NYTL and NBS information. I have not ignored it. However, it seemed reasonable to me to actually get and read Mallery's book, and to learn more about the issues involved before going off half-cocked. Now I'm looking into getting the reports themselves, and/or Mallery's papers regarding the reports (as well as Ellinger's comments). Seemed like the reasonable approach to me. Tom McDonald |
Copper Casting In America (Trevelyan)
Gary Coffman says in
: On Sat, 03 Jul 2004 00:38:46 GMT, Martyn Harrison wrote: I'm fascinated by the "meteoric copper" idea. I'm ok with the notion that elements up to Iron are formed by gradual fusion processes inside stars. But as far as I know, that's where these fusion processes stop. Copper isn't formed in that way. So I can't see how a lump of space debris could reasonably be copper. It could reasonably include a *bit* of copper, but not easily *be* a copper lump. Iron yes, you certainly get lumps of iron when, e.g. a supernova goes whomp, but copper, no I don't see how that's going to happen. So I find it enormously unlikely that a lump made predominantly of copper might end up as a meteor. Does anyone know if there is any credibility in this claim in practice? You're being confused by Eric's use of an obscure term of art for geochemically processed copper originating in a water saturated subsurface environment. All that "meteoric copper" means in this context is that it was deposited geochemically from a mildly acidic aqueous fluid whose watery origin was surface precipitation (rain-meteorology-meteoric), rather than liberation of water of hydration in the deep rock. A more complete explanation is that rainwater percolated down through faults in volcanic rock and reacted with volcanic sulphur to form a mild sulfuric acid solution. This acid solution, raised to temperatures on the order of 350C in the basement rock (and still liquid due to the high pressure there), then dissolved copper being held in more complex oxide or sulphide form in the deep rock, producing a solution of CuSO4. Over time, geologic processes forced this copper laden solution back up towards the cooler surface regions. When iron bearing rock was encountered, the reaction CuSO4 + Fe = FeSO4 + Cu resulted. Since copper and iron sulphates are soluble in water, they are free to move about in the rock following fissures and faults. But metallic copper isn't soluble in water, so after the reaction it is left behind to form "veins" of native copper in the rock matrix. Metallic copper is readily oxidized by Oxygen with dissolve clorine under acidic conditions. Forms copper chloride which is soluble in relative high concentrations. Nitrates and other acids that are also present can do similarly. The problem with Sulferic acid, the product of hydration of S03 produced by volcanism is that it is incredibly unstable, and tends to deprotonate protonating anything. This will result in the protonation of NaCl forming NaHSO4 and HCl which is capable of catalyzing the oxidation of metalic copper to copper I chloride. When this is neutralized the copper with precipitate, forming copper carbonates usually. It is a certain Irony of chemistry that sulfate is an oxidant, but because its so stable it generally doesn't act as an oxidant, but HCL which is technically a reductant can catalyze the oxidation of metals. The reason it can do this is that metals generally form a coat of oxide on the surface that prevent the underlying layers from oxidizing, the chloride ion, In the case of copper, although sulfate can solubilize copper I and II salts, the most common metal that coats copper is calcium or other common divalent cations. This is the reason its not good to have absolutely pure water running through copper, a small amount of calcium coats the copper and protects it. However calcium carbonates and calcium/copper complexes with carbonate are completely stable in acidic chloride solutions, and once the divalent cations are stripped from the surface of the copper it is free to oxidize with oxygen free radicals that are dissolved in water. Thus if the metalic copper is exposed to s acid sulphate solution, with contaminating salts of chlorine, floride or bromine, the consequence will be the oxidation of the metal. -- Philip - - - - - - - - - - - - - - - - - - - - - - - - - - - Mol. Anth. Group http://groups.yahoo.com/group/DNAanthro/ Mol. Evol. Hominids http://home.att.net/~DNAPaleoAnth/ Evol. of Xchrom. http://home.att.net/~DNAPaleoAnth/xlinked.htm Pal. Anth. Group http://groups.yahoo.com/group/Paleoanthro/ Sci. Arch. Aux http://groups.yahoo.com/group/sciarchauxilliary/ |
Copper Casting In America (Trevelyan)
Eric Stevens says in
: access to this information; however I have seen at least 2 video reports on the manufacturing of the comal, and they are not cast. The most similar cultural item I have seen is the hammered woks created from iron in china (which you can buy on the home shopping network if you are lucky). Woks being more sophisticated with handles, whereas the comal is just a large concave piece of copper. Why are you telling me about things that are not cast when I'm telling you about things which are? Eric, Inger logic doesn't work well even when she uses it, why would you think it would work better when you use it. You quoted a source that claimed that copper tool casting was prevelant from south american all the way to north america. That was your qoute. What I was doing was expanding upon the types of tools that the most prevalant copper cultures in the New World had made, aka not cast copper. IOW, I was descrediting your source and your quote, however obvious that was you failed to see it. My opinion is that, fundimentally, you're unfamiliar with mesoamerican culture. [Despite lengthy number of references I have given last year to educate you guys on the primary research on the evolution on New World metallurgy] I must ask you that question about your almost totally irrelevant and unhelpful response. That is, again, because you are unfamiliar with meso and south american culture. For my part, if you read that part of my previous article which you snipped, you will see that I was responding to Tom McDonalds reliance on Gary Coffman's comments on the Connor site quoting Mallery - as an adequate refutaion of Mallery's claims that some North American artifacts were cast. I quoted at length because Tom seemed unaware of the material inspite of it having been posted twice before in this (or a related) thread. And what I demonstrated was that casting was not the primary form of copper tool formation. IOW I am discrediting Mallory's claim by questioning whether casting was used for tools as ubiguitously as believed or was it for more experimental or recreational activities. The tool manufactoring industry in mesoamerica is no secret, what appears to be is the use of casting in that industry. Gary Coffman has not dealt with all of Mallery's claims. The claim of Mallery is self-discrediting, who needs to deal with it, Mallery. That's news to me. Mallery went south. You failed to get the point. I am by no means an expert on all metallurgy over all of the precolumbian americas (PCA) but I have yet to have seen a form or mold used in PCA to cast any metal object. If copper was routinely cast to form even trinkets, one would expect the molds for such object to be present somewhere. I am sure such molds probably exist somewhere; however I don't think that casting was a common practiced and was probably practiced amoung the elite metalurgist in the larger civilizations. What I have seen is pretty much what we talked about earlier with iron, in that partially smelted copper was fused by many men with mallets banging slag into comals. -- Philip - - - - - - - - - - - - - - - - - - - - - - - - - - - Mol. Anth. Group http://groups.yahoo.com/group/DNAanthro/ Mol. Evol. Hominids http://home.att.net/~DNAPaleoAnth/ Evol. of Xchrom. http://home.att.net/~DNAPaleoAnth/xlinked.htm Pal. Anth. Group http://groups.yahoo.com/group/Paleoanthro/ Sci. Arch. Aux http://groups.yahoo.com/group/sciarchauxilliary/ |
Copper Casting In America (Trevelyan)
On Sat, 03 Jul 2004 00:38:46 GMT, Martyn Harrison
originally top-posted but I have corrected this: Apparently on date Sat, 03 Jul 2004 10:44:05 +1200, Eric Stevens said: On Fri, 02 Jul 2004 06:02:01 GMT, Seppo Renfors wrote: Gary Coffman wrote: On Thu, 01 Jul 2004 08:26:52 GMT, Seppo Renfors wrote: Gary Coffman wrote: On Tue, 29 Jun 2004 05:48:01 GMT, Seppo Renfors wrote: Gary Coffman wrote: [..] Again, porosity is the problem, and that should show up on radiographs, as it does for R666 (which certainly shows evidence of being melted in atmosphere, though not necessarily evidence of being cast), but none of the other artifacts presented show that sort of porosity. See: http://www.iwaynet.net/~wdc/copper.htm The 4th and 5th pictures down. Those pictures do not show any evidence of the characteristic porosity copper casting would produce. They disagree with you as it states "The casting bubble can clearly been seen...." And as I note below, they are quite wrong. It is rather obvious that they have little practical experience or knowledge about working native copper. It behaves significantly differently from other metals when melted or cast. Copper is copper no matter what part of the world it is in. ALLOYS vary from place to place. So I find it hard to accept Michigan "native copper" is much different from that here in Australia. Michigan native copper is 'meteoric' copper. Australia does have some meteoric copper (see http://www.econs.ecel.uwa.edu.au/AMH...ett/news21.htm) but it is accessible in quantitities very much smaller than in NA. I would also direct your attention to this: http://people.uncw.edu/simmonss/P6030052.JPG There is little question this has been melted - and where are the obvious faults? Your authorities are a dentist, an engineer whose expertise is with iron and steel, and one chemist (who disagrees with 4 others at his school). Frankly, not a very impressive collection of authorities on the metallurgy of native copper. If you go to purchase a bottle of wine, which is the most important - the label on the bottle or the taste of the content? The above is pointing to the label, ignoring the content. The single large surface bubble is a blister, common when the surface of a wrought piece is overheated. Compare it to the radiograph of R666. The latter does show the characteristic deep pattern of porosity of an at least partially melted copper object. [..] I'm fascinated by the "meteoric copper" idea. 'meteoric copper' is copper precipitated by the action of 'meteoric water'. See http://www.webref.org/geology/m/meteoric_water.htm and http://www.ocf.berkeley.edu/~tarcuri/finalproposal.html "After hydrofracturing, temperature gradients and increased permeability along fractures caused meteoric waters to circulate through the pluton, effectively leaching metals from the porphyry and precipitating them in hypogene, hydrothermal veins." Apart from that, your interpretation of the term 'meteoric' as referring to wacking great lumps of copper from space is understandable but incorrect. I'm ok with the notion that elements up to Iron are formed by gradual fusion processes inside stars. But as far as I know, that's where these fusion processes stop. Copper isn't formed in that way. So I can't see how a lump of space debris could reasonably be copper. It could reasonably include a *bit* of copper, but not easily *be* a copper lump. Iron yes, you certainly get lumps of iron when, e.g. a supernova goes whomp, but copper, no I don't see how that's going to happen. So I find it enormously unlikely that a lump made predominantly of copper might end up as a meteor. Does anyone know if there is any credibility in this claim in practice? I hope not. Eric Stevens |
Copper Casting In America (Trevelyan)
On Fri, 02 Jul 2004 23:02:57 -0400, Gary Coffman
wrote: On Sat, 03 Jul 2004 00:38:46 GMT, Martyn Harrison wrote: I'm fascinated by the "meteoric copper" idea. I'm ok with the notion that elements up to Iron are formed by gradual fusion processes inside stars. But as far as I know, that's where these fusion processes stop. Copper isn't formed in that way. So I can't see how a lump of space debris could reasonably be copper. It could reasonably include a *bit* of copper, but not easily *be* a copper lump. Iron yes, you certainly get lumps of iron when, e.g. a supernova goes whomp, but copper, no I don't see how that's going to happen. So I find it enormously unlikely that a lump made predominantly of copper might end up as a meteor. Does anyone know if there is any credibility in this claim in practice? You're being confused by Eric's use of an obscure term of art for geochemically processed copper originating in a water saturated subsurface environment. All that "meteoric copper" means in this context is that it was deposited geochemically from a mildly acidic aqueous fluid whose watery origin was surface precipitation (rain-meteorology-meteoric), rather than liberation of water of hydration in the deep rock. My use of the term is correct. There are all kinds of ways of forming copper deposits of all kinds of purities. The unusually high purity of the Michigan deposits is attributable to the their 'meteoric' origin. A more complete explanation is that rainwater percolated down through faults in volcanic rock and reacted with volcanic sulphur to form a mild sulfuric acid solution. This acid solution, raised to temperatures on the order of 350C in the basement rock (and still liquid due to the high pressure there), then dissolved copper being held in more complex oxide or sulphide form in the deep rock, producing a solution of CuSO4. Over time, geologic processes forced this copper laden solution back up towards the cooler surface regions. When iron bearing rock was encountered, the reaction CuSO4 + Fe = FeSO4 + Cu resulted. Since copper and iron sulphates are soluble in water, they are free to move about in the rock following fissures and faults. But metallic copper isn't soluble in water, so after the reaction it is left behind to form "veins" of native copper in the rock matrix. To go into excruciating detail on this process requires knowledge of physical chemistry, equilibrium solutions, and a good bit of geology to understand why it works as it does. For example, I'd expect objections from the lay person that since there is iron in the deep rock too, the geochemical refining process should have redeposited the copper there. But it doesn't, because the high temperature and pressure in the deep rock shifts the equilibrium point of the reaction in an unfavorable direction for that to occur. Higher up, where temperatures and pressures are lower, the reaction can proceed to a more favorable equilibrium with respect to copper precipitation. (There are other factors too, but I'm not going to write a geochemical treatise here.) In any event, this natural geochemical refining process means that native copper (meteoric copper) consists of veins of extremely pure crystalline copper. This is what makes native copper so desirable, it doesn't have to be smelted or further chemically refined, it merely needs to be mechanically separated from the rock through which the veins pass. Just as veins in the body come in different sizes, so too do ore veins in a rock matrix. The vein can be hair thin, or several feet in diameter, or any size in between. That means chunks of native copper come in all sizes, allowing the ancient craftsman working at a sufficiently rich site of native copper, such as Keweenaw, to choose the size of raw material appropriate for making whatever artifact he chose. Gary Eric Stevens |
Copper Casting In America (Trevelyan)
On Sat, 03 Jul 2004 01:29:01 GMT, Seppo Renfors
wrote: Eric Stevens wrote: On Fri, 02 Jul 2004 06:02:01 GMT, Seppo Renfors wrote: Gary Coffman wrote: On Thu, 01 Jul 2004 08:26:52 GMT, Seppo Renfors wrote: Gary Coffman wrote: On Tue, 29 Jun 2004 05:48:01 GMT, Seppo Renfors wrote: Gary Coffman wrote: [..] Again, porosity is the problem, and that should show up on radiographs, as it does for R666 (which certainly shows evidence of being melted in atmosphere, though not necessarily evidence of being cast), but none of the other artifacts presented show that sort of porosity. See: http://www.iwaynet.net/~wdc/copper.htm The 4th and 5th pictures down. Those pictures do not show any evidence of the characteristic porosity copper casting would produce. They disagree with you as it states "The casting bubble can clearly been seen...." And as I note below, they are quite wrong. It is rather obvious that they have little practical experience or knowledge about working native copper. It behaves significantly differently from other metals when melted or cast. Copper is copper no matter what part of the world it is in. ALLOYS vary from place to place. So I find it hard to accept Michigan "native copper" is much different from that here in Australia. Michigan native copper is 'meteoric' copper. I really hate these poncy misleading terms like "meteoric" copper and "native" copper when perfectly good clear terms are available to use like "pure", "nugget", "vein"...... Hmmmm.... does that then meant that "meteoric iron" isn't really "meteoric" or extraterrestrial at all? Australia does have some meteoric copper (see http://www.econs.ecel.uwa.edu.au/AMH...ett/news21.htm) but it is accessible in quantitities very much smaller than in NA. Yes, this is virtually my "back yard". There has been copper mining all along the Flinders Ranges, from North to South as well as on York Peninsular (Moonta - Wallaroo - Kadina districts, the "copper triangle"). But the Michigan copper and, presumably, the Balfour meteoric copper is of an unusually high purity. A few kilometres from here is a perfectly good diamond pipe as well..... only they built a town over it, and the centre of the pipe is under the local footy oval... can't disrupt the footy you know! The fact that they are lesser quantities doesn't really alter their composition. CU is CU wherever it is, irrespective of quantities. [..] Eric Stevens |
Copper Casting In America (Trevelyan)
On Sat, 03 Jul 2004 04:12:21 GMT, Philip Deitiker
wrote: Eric Stevens says in : access to this information; however I have seen at least 2 video reports on the manufacturing of the comal, and they are not cast. The most similar cultural item I have seen is the hammered woks created from iron in china (which you can buy on the home shopping network if you are lucky). Woks being more sophisticated with handles, whereas the comal is just a large concave piece of copper. Why are you telling me about things that are not cast when I'm telling you about things which are? Eric, Inger logic doesn't work well even when she uses it, why would you think it would work better when you use it. You quoted a source that claimed that copper tool casting was prevelant from south american all the way to north america. That was your qoute. What I was doing was expanding upon the types of tools that the most prevalant copper cultures in the New World had made, aka not cast copper. IOW, I was descrediting your source and your quote, however obvious that was you failed to see it. My opinion is that, fundimentally, you're unfamiliar with mesoamerican culture. [Despite lengthy number of references I have given last year to educate you guys on the primary research on the evolution on New World metallurgy] I must ask you that question about your almost totally irrelevant and unhelpful response. That is, again, because you are unfamiliar with meso and south american culture. Even if I wasn't, the knowledge has almost nothing to do with NA copper. For my part, if you read that part of my previous article which you snipped, you will see that I was responding to Tom McDonalds reliance on Gary Coffman's comments on the Connor site quoting Mallery - as an adequate refutaion of Mallery's claims that some North American artifacts were cast. I quoted at length because Tom seemed unaware of the material inspite of it having been posted twice before in this (or a related) thread. And what I demonstrated was that casting was not the primary form of copper tool formation. IOW I am discrediting Mallory's claim by questioning whether casting was used for tools as ubiguitously as believed or was it for more experimental or recreational activities. The tool manufactoring industry in mesoamerica is no secret, what appears to be is the use of casting in that industry. A question by you is sufficient to discredit something? Gee! You must be important! Gary Coffman has not dealt with all of Mallery's claims. The claim of Mallery is self-discrediting, who needs to deal with it, Mallery. That's news to me. Mallery went south. You failed to get the point. It might look that way but only because you (again) snipped some of my text without indicating the fact. Some people regard this as a dishonest practice. I am by no means an expert on all metallurgy over all of the precolumbian americas (PCA) but I have yet to have seen a form or mold used in PCA to cast any metal object. If copper was routinely cast to form even trinkets, one would expect the molds for such object to be present somewhere. I am sure such molds probably exist somewhere; however I don't think that casting was a common practiced and was probably practiced amoung the elite metalurgist in the larger civilizations. What I have seen is pretty much what we talked about earlier with iron, in that partially smelted copper was fused by many men with mallets banging slag into comals. Eric Stevens |
Copper Casting In America (Trevelyan)
On Fri, 02 Jul 2004 22:11:26 -0500, Tom McDonald
wrote: Eric Stevens wrote: On Fri, 02 Jul 2004 02:50:07 -0500, Tom McDonald wrote: Eric Stevens wrote: snip I haven't been able to track down Mallery's papers. As to whether or not they would be interpreted differently today - I very much doubt it. The text quoted by Mallery is most basic metallurgy. I've just emailed both the NYTL and the NIST about these reports. Probably a lost cause, but what the hell. Good idea. I was tempted to do that but never got around to it. I would be surprised if they had the relevant files after all these years. Eric, I heard back from the librarian at the NIST. He says they don't have L-C 444 anymore, but that is because it's missing, not because they don't curate them. (It turns out that L-C 445 is about painting radiators in steam heat systems :-)) He said he would contact other libraries that maintain collections of the old NBS Letter-Circulars. If he gets a copy, he will snail-mail a copy to me; if not, he'll tell me 'no joy'. Still waiting to hear from New York Testing Labs. They apparently were bought by a larger firm a few years ago, but it looks like they maintained their name. The work they did, at least on the three indicated artifacts, probably was done on contract with the National Museum of Natural History. If so, the Museum might have to consent to releasing the report, if NYTL still has it. Who did you contact about Mallery's papers? Would it help, do you think, for me to contact them as well? It vanished with a past computer crash. I originally wrote to the Smithsonian and they then referred me to a person at the (?) National archives (?). I contacted that person who referred me to another who never gave me a meaningful response no matter how I (gently) pressed them. I think a fresh start is a very good idea. However, please note that the NBS report Mallery cites on page 223, Letter-Circular 444, July 13, 1935, is _not_ the source of the quotation by Dr. George P. Ellinger on page 225, quoted by you below. The quotation by Ellinger has to have been made _after_ the NYTL report; and as I note below, the NYTL testing had to have been done at least a decade after NBS L-C 444. We don't know whether Ellinger is being quoted from a report, a letter, a conversation, or what. We can't follow up on this to see whether Mallery got it right. I agree. I'm trying to use Mallery as incontestable proof of copper casting. I was merely disputing the implication that Gary Coffman had settled the matter. Oops - I meant "I'm NOT trying ... " I never said that the matter was settled. Gary and Paul have lent us expertise I don't have, and as I learn more, I'm trying to apply it correctly to the info I have. I think that soon I'll know enough to at least ask reasonable and germane questions of the literature, and living archaeologists. Them's good fun! Important words from the quote from Mallery include: "X-RAY EXAMINATION:—The tools were radiographed using standard techniques. A review of the radiographs led to the following observations:— # I—The three tools were originally cast." "The specimens are originally cast but apparently have been reheated and worked to some extent." This was the testing done at the behest of James A. Ford of the American Museum of Natural History, per Mallery. Ford began his tenure at the Museum sometime in 1946: http://www.mnsu.edu/emuseum/informat...ord_james.html or http://makeashorterlink.com/?J567224B8 "Following this report, six leading American museums furnished tools from the United States, Canada, Mexico, Guatemala, and Peru for testing. Various metallurgists who have examined the micrographs of these tools concur in the findings of the New York Testing Laboratories, Inc. that many of the specimens examined have been cast. Dr. George P. Ellinger, metallurgist for the National Bureau of Standards, said, after examining the submitted specimens, "The presence of cuprous oxide in the interior of the tools tested and the concavity caused by shrinking justify the conclusion that the vast majority of the ancient tools were cast." Even if Mallery quoted accurately from the NYTL and George Ellinger, we are still left with the problem that neither the NYTL report, or the statement by Ellinger, state what Gary and Paul assure us would have been obvious from the radiographs; characteristic porosities. Internal small bubbles. Many. With respect to Gary, the fact that he did not know of the use of coal or carbon to deoxidise molten copper suggests that his is not the final word on the subject. Again, never said any one person would have all the pieces of the puzzle. However, Gary certainly knows more than I did; and Paul is adding more still. BTW, in another post (to Phil, I think) you said that I seemed to have not seen, or to have ignored, the NYTL and NBS information. I have not ignored it. However, it seemed reasonable to me to actually get and read Mallery's book, and to learn more about the issues involved before going off half-cocked. Now I'm looking into getting the reports themselves, and/or Mallery's papers regarding the reports (as well as Ellinger's comments). Seemed like the reasonable approach to me. Tom McDonald Eric Stevens |
Copper Casting In America (Trevelyan)
Eric Stevens wrote:
On Fri, 02 Jul 2004 22:11:26 -0500, Tom McDonald wrote: snip Who did you contact about Mallery's papers? Would it help, do you think, for me to contact them as well? It vanished with a past computer crash. I originally wrote to the Smithsonian and they then referred me to a person at the (?) National archives (?). I contacted that person who referred me to another who never gave me a meaningful response no matter how I (gently) pressed them. I think a fresh start is a very good idea. Eric, Yup, I agree. I guess I have to, since your crash leaves us bereft of stale starts :-). I'd appreciate any thoughts you have on contacting folks about this. Wasn't there some small museum that might have received Mallery's papers after his death? snip We don't know whether Ellinger is being quoted from a report, a letter, a conversation, or what. We can't follow up on this to see whether Mallery got it right. I agree. I'm trying to use Mallery as incontestable proof of copper casting. I was merely disputing the implication that Gary Coffman had settled the matter. Oops - I meant "I'm NOT trying ... " I figured that. You don't suppose I'd let that pitch hang up there if I thought you actually *meant* it as written, do you? :-). Tom McDonald |
Copper Casting In America (Trevelyan)
Gary Coffman wrote: On Fri, 02 Jul 2004 07:53:30 GMT, Seppo Renfors wrote: Gary Coffman wrote: On Thu, 01 Jul 2004 12:10:10 GMT, Seppo Renfors wrote: Gary Coffman wrote: On Tue, 29 Jun 2004 07:05:25 GMT, Seppo Renfors wrote: This has a good story about the Great lakes Copper deposits. http://www.geo.msu.edu/geo333/copper.html As that article notes, 14 billion pounds of copper have been removed from the area since the ancients were working copper there. Let the enormity of that number sink in. There was an *awful lot* of copper there in ancient times, much of it easily accessible from the surface. My main interest was to show the formation of the copper deposits - the volcanic activity that melted it (and other minerals with it). Silver is/was found in fair quantities alongside the copper. What isn't known - because nobody cares to find out, is the composition of the metal used in the artefacts. It is ASSUMED to be pure copper. The presence of silver inclusions *proves* the native copper was not melted after being deposited. ...but only for that piece - not for any other piece. Further more IIRC there is a method of laminating copper and silver sheet and carving through one into the other. It is a Japanese technique IIRC. It requires being heated under pressure, to the point the silver just starts "sweating" and it brazes the sheets together. So silver in copper can also be deliberate - as decoration. It is called silver brazing (or more commonly, but incorrectly, called silver soldering). I already said it was brazing. I couldn't think of the specific decoration name before, but it is used in making "mokume gane" as found, and originating on samurai sword handles from about 1600 - 1800. It is a common technique used to join pieces of copper. Pressure is not required. A temperature in excess of 800F is required for brazing to occur (by ASTM definition). Are you suggesting silver "sweats" (forms liquid beads) way below its melting point? Native copper is deposited by chemical means, not volcanic melting and extrusion. I already posted this earlier. It disagrees with you: http://www.geo.msu.edu/geo333/copper.html "chemical" doesn't get a single mention. Actually, it doesn't disagree with me. It says the copper was carried in an aqueus solution from great depths and deposited in the vents, fissures, and voids of the iron bearing rocks above. The pertinent chemical reaction involved is CuSO4 + Fe(Metal) = FeSO4 + Cu (Metal) If you were knowledgeable of the chemistry of copper, this would have been obvious to you. If you had read any of the many geochemical references in the links already provided in this thread, it would have been spelled out for you in excruciating detail. If you had not been so intent on being snaky you would know that "aqueous" (correct spelling) also means "water like", "watery" as well as "of or containing water" - therefor it is NOT a clear explanatory term in itself. Further to that, you would NOT have written that formula up there - but if you want to argue that particular formula (A) point out how two solids, suddenly for no given reason, decides to react and change (B) how they get together in the first place when they are NOT ambulatory in any way. Oh and where are these pure iron deposits, hmmm? It sure as hell would have saved on building blast furnaces if that existed... You could have instead pointed to this section in that same article: "Into the lava flows of Keweenaw, Houghton, and Ontonagon counties percolating hot waters rising from great depths brought copper and silver in solution. As it cooled, the waters filled the fissures and the gas cavities (amygdules) of the lavas (trap rocks) with pure copper and silver..." Now here we see something totally different from your "formula". There IS a mention of a "solution" - most likely the copper portion was CuSO4.5H2O. There is not a single mention of iron. It also refers to a heat source - not two ambulatory minerals meeting in the dark for a bit of kissy kissy, saliva swapping or any other hanky-panky! So what have we here - we have the result of hot lava, the water "evaporates" leaving what would be known as, Blue copper, Blue stone or Blue vitriol (among other things) or CuSO4. Indeed it does exist, but it isn't your pure Cu, is it. BUT if I again go back to your "formula" and introduce some "Fe" into the equation, it has to be as "FeSO4.H2O" solution - 100% water soluble (used in animal feeds as a supplement). Perhaps more interesting is the FeSO4.7H2O (copperas), also water soluble, but is blue in colour similar to copper sulphate and in its solid form it melts at 64 deg. C! Only problem is that this requires no hanky-panky at all.... the Fe is pregnant with SO4 already! So lets add the bit of "mood" to the situation and heat it up with the cooling lava. The result would indeed be ferrous and cupric oxides, respectively, giving off water and sulphur trioxide, which combine to produce a dilute solution of sulphuric acid. So IF there is either some "copperas" or Ferrous Sulphate Monohydrate in the CuSO4.5H2O - then one can expect IRON to be present with the copper - well.... yes but not in the same place by the look of it. But then if we take both the copper and Iron out of the soup we end up with H2SO4.... or masses of sulphuric acid (oil of vitriol)! Therefor Lake Superior is a lake of acid. Then the Moral of the Story is: don't eat the fish as they will eat your insides out! Now, I have to admit I have have happily forgotten 99% of what I ever learned about chemistry (except that needed to make moonshine), but then again, why on earth am I required to know any of it.....?? To prevent you getting all snooty by suggesting things?? [..] -- SIR - Philosopher unauthorised ----------------------------------------------------------------- The one who is educated from the wrong books is not educated, he is misled. ----------------------------------------------------------------- |
Copper Casting In America (Trevelyan)
Eric Stevens wrote: On Fri, 02 Jul 2004 13:37:36 GMT, Seppo Renfors wrote: [..] However if one considers that "bubbling" has been claimed to be caused by "overheating" in a annealing process - then it is saying "melted" at the same time, as it cannot bubble UNLESS a portion of it is melted. Also "welding" requires the melting of the metal - or so goddamned close to it that the friction heat generated by a blow on it does melt the metal. Reasonably pure copper can be welded at ambient temperatures merely by pressure. MIllions of electrical connections rely on this property. Anything can be welded at virtually any temperature by using pressure. The Mini Minor crown wheel for the diff started off as a steel disc cut off from a round billet. This was placed on a mould at the end of a hydraulic ram, and the other half of the mould was on another hydraulic ram. To form the crown wheel they were slammed together under huge pressure - it made a very nice crown wheel - and fast! [..] -- SIR - Philosopher unauthorised ----------------------------------------------------------------- The one who is educated from the wrong books is not educated, he is misled. ----------------------------------------------------------------- |
Copper Casting In America (Trevelyan)
On Fri, 02 Jul 2004 13:37:36 GMT, Seppo Renfors wrote:
Tom McDonald wrote: Seppo Renfors wrote: Gary Coffman wrote: On Tue, 29 Jun 2004 05:48:01 GMT, Seppo Renfors wrote: Gary Coffman wrote: [..] Again, porosity is the problem, and that should show up on radiographs, as it does for R666 (which certainly shows evidence of being melted in atmosphere, though not necessarily evidence of being cast), but none of the other artifacts presented show that sort of porosity. See: http://www.iwaynet.net/~wdc/copper.htm The 4th and 5th pictures down. Those pictures do not show any evidence of the characteristic porosity copper casting would produce. They disagree with you as it states "The casting bubble can clearly been seen...." Gary showed that the porosity typical of pure cast copper is not present in that artifact. He even explained in just below. Please point out the "porosity" in this sample: Two copper pigs: http://people.uncw.edu/simmonss/P6030052.JPG The evidence of porosity is available to the naked eye in that thin copper flake. There are dozens of tiny bubbles in evidence, You don't even need a radiograph to see them. A radiograph or a density test would settle the matter absolutely, but neither is really needed here as the sizes and numbers of bubbles already visible are clear indications of atmospheric melting. The casting is obvious in this: http://people.uncw.edu/simmonss/LA_1240-1.4.jpg The large numbers of tiny pits in that piece are suggestive of porosity, but a stereo radiograph, or a density measurement, would be required to determine if the piece is actually riddled with porosity, or if we're just seeing corrosion pitting of otherwise sound copper (if the object is indeed copper, and not a bronze alloy). Both pictures show melted copper - pre Colombian melted copper! It leaves Gary's statements hanging in the air. Pre-Columbian, or Spanish Conquest? I don't see a precise dating associated with the individual objects. The web site says the collection of objects date from the Post Classic and Spanish colonial periods. Also, the web site says the objects are a mix of copper, copper-tin bronze, and copper-arsenic bronze. What evidence do you have that the two particular objects you selected from that collection are pure copper rather than bronze? However if one considers that "bubbling" has been claimed to be caused by "overheating" in a annealing process - then it is saying "melted" at the same time, as it cannot bubble UNLESS a portion of it is melted. Also "welding" requires the melting of the metal - or so goddamned close to it that the friction heat generated by a blow on it does melt the metal. You're wrong on both counts. Copper is a malleable, ie plastic, material even at room temperature. At annealing temperature (500F or greater) it is much more so. Bubble gum need not be molten for bubbles to be formed in it, neither does copper. And while copper can be welded, in an inert atmosphere, by melting, it can also be welded at lower temperature by pressure. Those are two logical examples of melting occurring - the knowledge of melting copper existed. It beggars belief that scraps and off cuts were NOT melted when the process must have been known to them. That people suggest they would rather go and do hard manual labour another day to find a piece "just right" for the job, when it is right there, right now, right before them. All they have to do is melt it into one lump. And wind up with a porous lump of no use to anyone. Really, you haven't absorbed anything anyone has been telling you about the atmospheric casting of pure copper. The implied suggestion they would rather do the hard labour, and not proceed with the easier option available immediately to them, isn't consistent with known human behaviour. That's your interpretation. But since your interpretation is wrong, your conclusion is also wrong. Gary |
Copper Casting In America (Trevelyan)
On Fri, 2 Jul 2004 18:09:16 -0500, "Paul K. Dickman" wrote:
In order to illustrate the nature of the porosity in melted copper I put a few pictures up. Well done, Paul. Nothing like actually working with the metal to demonstrate its properties. Gary |
Copper Casting In America (Trevelyan)
On Thu, 01 Jul 2004 12:26:31 GMT, Seppo Renfors wrote:
Gary Coffman wrote: On Wed, 30 Jun 2004 14:53:00 -0400, Yuri Kuchinsky wrote: Gary Coffman wrote: [snip] The apparent fact that the Native Americans *didn't* cast native copper This is a "fact" only if you disregard all evidence to the contrary, as you appear to be doing. Virtually all of the evidence presented to date in this thread is against casting of ancient Michigan native copper artifacts. If you have conclusive evidence showing characteristic porosity in all the items claimed to be cast, if you have evidence showing a chemical analysis of true alloying between the native copper and other metals (mainly silver) found with it in the halfbreed ore matrix, if you have evidence of large numbers of identically dimensioned artifacts representative of a casting provenance, etc, then present it. Otherwise you have no case. You cannot claim "you have no case" UNLESS you prove there is no "true alloying between the native copper and other metals" and that takes an analysis of the metals in the artefacts found. It works both ways you know. Actually, I can make the claim, because heavily alloyed copper is no longer native copper. What we do know is that ancient Michigan artifacts have been found with silver inclusions. That precludes the possibility that they were ever melted. No, it precludes that item from having been melted only. You cannot extrapolate that beyond the artefact itself. It is a conclusive indication for any case where silver inclusions are found. We do know that of the artifacts which have been put forward as evidence of copper casting, all but one do *not* show the characteristic porosity of atmospheric melting of copper, and that one does not appear to be a deliberate casting. We see TWO artefacts being claimed as being cast - one being conceded as being cast. We don't know the composition of the metal of the second artefact to be able to discard it as "not cast". Neither Tom or I have conceded R666 was cast. We've agreed it shows all the characteristic signs of atmospheric melting, but it doesn't automatically follow that it was deliberately cast. You have claimed it is the sign of "copper" being overheated - ie to melting point else bubbles cannot form. At the same time you have also stated the heat source has to be forced air type to get it hot enough to melt copper. Copper does not need to be heated to melting for blisters to form. Please go back and reread Neubauer for examples of native copper which blistered on annealing *without* being raised to melting temperature. You can blow bubbles in bubble gum without melting it, you can do the same in copper. It merely has to reach a sufficient state of plasticity for the gas pressure from inclusions to deform it into a blister. I see those two statements as being inconsistent with each other. If the Copper was simply hammered and annealed, the temp should NOT be able to get high enough to cause any bubbling. Well, then you're wrong. Gary |
Copper Casting In America (Trevelyan)
On Sat, 03 Jul 2004 07:38:25 GMT, Seppo Renfors
wrote: Eric Stevens wrote: On Fri, 02 Jul 2004 13:37:36 GMT, Seppo Renfors wrote: [..] However if one considers that "bubbling" has been claimed to be caused by "overheating" in a annealing process - then it is saying "melted" at the same time, as it cannot bubble UNLESS a portion of it is melted. Also "welding" requires the melting of the metal - or so goddamned close to it that the friction heat generated by a blow on it does melt the metal. Reasonably pure copper can be welded at ambient temperatures merely by pressure. MIllions of electrical connections rely on this property. Anything can be welded at virtually any temperature by using pressure. The Mini Minor crown wheel for the diff started off as a steel disc cut off from a round billet. This was placed on a mould at the end of a hydraulic ram, and the other half of the mould was on another hydraulic ram. To form the crown wheel they were slammed together under huge pressure - it made a very nice crown wheel - and fast! You are confusing forging with welding. Eric Stevens |
Copper Casting In America (Trevelyan)
On Sat, 03 Jul 2004 01:38:33 -0500, Tom McDonald
wrote: Eric Stevens wrote: On Fri, 02 Jul 2004 22:11:26 -0500, Tom McDonald wrote: snip Who did you contact about Mallery's papers? Would it help, do you think, for me to contact them as well? It vanished with a past computer crash. I originally wrote to the Smithsonian and they then referred me to a person at the (?) National archives (?). I contacted that person who referred me to another who never gave me a meaningful response no matter how I (gently) pressed them. I think a fresh start is a very good idea. Eric, Yup, I agree. I guess I have to, since your crash leaves us bereft of stale starts :-). I'd appreciate any thoughts you have on contacting folks about this. Wasn't there some small museum that might have received Mallery's papers after his death? Only if you call the Smithsonian small. :-) My contact there did confirm that they once had them. snip We don't know whether Ellinger is being quoted from a report, a letter, a conversation, or what. We can't follow up on this to see whether Mallery got it right. I agree. I'm trying to use Mallery as incontestable proof of copper casting. I was merely disputing the implication that Gary Coffman had settled the matter. Oops - I meant "I'm NOT trying ... " I figured that. You don't suppose I'd let that pitch hang up there if I thought you actually *meant* it as written, do you? :-). Tom McDonald Eric Stevens |
Copper Casting In America (Trevelyan)
On Sat, 03 Jul 2004 07:27:39 GMT, Seppo Renfors
wrote: Gary Coffman wrote: On Fri, 02 Jul 2004 07:53:30 GMT, Seppo Renfors wrote: Gary Coffman wrote: On Thu, 01 Jul 2004 12:10:10 GMT, Seppo Renfors wrote: Gary Coffman wrote: On Tue, 29 Jun 2004 07:05:25 GMT, Seppo Renfors wrote: This has a good story about the Great lakes Copper deposits. http://www.geo.msu.edu/geo333/copper.html As that article notes, 14 billion pounds of copper have been removed from the area since the ancients were working copper there. Let the enormity of that number sink in. There was an *awful lot* of copper there in ancient times, much of it easily accessible from the surface. My main interest was to show the formation of the copper deposits - the volcanic activity that melted it (and other minerals with it). Silver is/was found in fair quantities alongside the copper. What isn't known - because nobody cares to find out, is the composition of the metal used in the artefacts. It is ASSUMED to be pure copper. The presence of silver inclusions *proves* the native copper was not melted after being deposited. ...but only for that piece - not for any other piece. Further more IIRC there is a method of laminating copper and silver sheet and carving through one into the other. It is a Japanese technique IIRC. It requires being heated under pressure, to the point the silver just starts "sweating" and it brazes the sheets together. So silver in copper can also be deliberate - as decoration. It is called silver brazing (or more commonly, but incorrectly, called silver soldering). I already said it was brazing. I couldn't think of the specific decoration name before, but it is used in making "mokume gane" as found, and originating on samurai sword handles from about 1600 - 1800. It is a common technique used to join pieces of copper. Pressure is not required. A temperature in excess of 800F is required for brazing to occur (by ASTM definition). Are you suggesting silver "sweats" (forms liquid beads) way below its melting point? Native copper is deposited by chemical means, not volcanic melting and extrusion. I already posted this earlier. It disagrees with you: http://www.geo.msu.edu/geo333/copper.html "chemical" doesn't get a single mention. Actually, it doesn't disagree with me. It says the copper was carried in an aqueus solution from great depths and deposited in the vents, fissures, and voids of the iron bearing rocks above. The pertinent chemical reaction involved is CuSO4 + Fe(Metal) = FeSO4 + Cu (Metal) If you were knowledgeable of the chemistry of copper, this would have been obvious to you. If you had read any of the many geochemical references in the links already provided in this thread, it would have been spelled out for you in excruciating detail. If you had not been so intent on being snaky you would know that "aqueous" (correct spelling) also means "water like", "watery" as well as "of or containing water" - therefor it is NOT a clear explanatory term in itself. Further to that, you would NOT have written that formula up there - but if you want to argue that particular formula (A) point out how two solids, suddenly for no given reason, decides to react and change (B) how they get together in the first place when they are NOT ambulatory in any way. http://www.cop.ufl.edu/safezone/prok...5100/eumix.htm illustrates the basic mechanism. The same kind of thing happens with copper and silver. The presence of silver will lower the melting point of the copper and a solid solution will be formed. In the case of copper and silver http://www.bipm.fr/metrologia/ViewAr...=25&PAGE=41-47 gives the lowest melting temperature as 779.583 plus-minus 0.060 which is lower than the melting point of either copper or silver. Many metals will form similar eutectic mixtures with copper, particularly aluminium and zinc. Some tin-lead solders will form eutectic mixtures with high alloy steels at quite low temperatures, which is why at an early stage they stopped soldering identifying labels onto aircraft undercarriage legs. :-) Oh and where are these pure iron deposits, hmmm? It sure as hell would have saved on building blast furnaces if that existed... You could have instead pointed to this section in that same article: "Into the lava flows of Keweenaw, Houghton, and Ontonagon counties percolating hot waters rising from great depths brought copper and silver in solution. As it cooled, the waters filled the fissures and the gas cavities (amygdules) of the lavas (trap rocks) with pure copper and silver..." Now here we see something totally different from your "formula". There IS a mention of a "solution" - most likely the copper portion was CuSO4.5H2O. There is not a single mention of iron. It also refers to a heat source - not two ambulatory minerals meeting in the dark for a bit of kissy kissy, saliva swapping or any other hanky-panky! So what have we here - we have the result of hot lava, the water "evaporates" leaving what would be known as, Blue copper, Blue stone or Blue vitriol (among other things) or CuSO4. Indeed it does exist, but it isn't your pure Cu, is it. BUT if I again go back to your "formula" and introduce some "Fe" into the equation, it has to be as "FeSO4.H2O" solution - 100% water soluble (used in animal feeds as a supplement). Perhaps more interesting is the FeSO4.7H2O (copperas), also water soluble, but is blue in colour similar to copper sulphate and in its solid form it melts at 64 deg. C! Only problem is that this requires no hanky-panky at all.... the Fe is pregnant with SO4 already! I suggest you read the opening paragraphs of http://www.minsocam.org/MSA/collecto...r/vft/mi2c.htm Please don't take this as a contradiction. I intend it as an elucidation. :-) So lets add the bit of "mood" to the situation and heat it up with the cooling lava. The result would indeed be ferrous and cupric oxides, respectively, giving off water and sulphur trioxide, which combine to produce a dilute solution of sulphuric acid. So IF there is either some "copperas" or Ferrous Sulphate Monohydrate in the CuSO4.5H2O - then one can expect IRON to be present with the copper - well.... yes but not in the same place by the look of it. But then if we take both the copper and Iron out of the soup we end up with H2SO4.... or masses of sulphuric acid (oil of vitriol)! Therefor Lake Superior is a lake of acid. Then the Moral of the Story is: don't eat the fish as they will eat your insides out! Now, I have to admit I have have happily forgotten 99% of what I ever learned about chemistry (except that needed to make moonshine), but then again, why on earth am I required to know any of it.....?? To prevent you getting all snooty by suggesting things?? [..] Eric Stevens |
Copper Casting In America (Trevelyan)
On Thu, 01 Jul 2004 13:26:15 GMT, Seppo Renfors wrote:
I am aware of one piece of copper 17 ton of it (Yank ton presumably - a short measure). It was found on the bottom of Lake Superior. I'm also aware of another large find of several tons, but a VERY long way underground in a modern mine. Neither kind of find was available to the native people. Then become aware of this from http://www.geo.msu.edu/geo333/copper_ii.html "A huge copper boulder on the Ontonagon River, said by Alexander Henry (the first white man to describe it) to weigh five tons led, in 1770, to the first copper mining venture in the UP. This first mining venture started near the boulder that lay 20 miles from the mouth of the Ontonagon River. The "Ontonagon Boulder" was eventually shipped to the Smithsonian Museum and now resides by the Mall Entrance to the Museum of Natural History. Michigan has been trying to get our Boulder back, but the negotiations are a bit slow. You know what happens when things go to Washington. It is about the size of a VW Bug and weighs about 5 tons. " Other large "mass copper" pieces have been found on the surface in the UP. One article I came across while googling said that some of the large masses show evidence that ancient peoples had made attempts to flake pieces off of them (tool marks). Here's another example of "mass copper" http://64.90.169.191/education/histo...es/copboy4.gif And he http://www.geo.msu.edu/geo333/images/mass-copper.jpg Gary |
Copper Casting In America (Trevelyan)
On Sat, 03 Jul 2004 04:54:31 -0400, Gary Coffman
wrote: On Thu, 01 Jul 2004 12:26:31 GMT, Seppo Renfors wrote: Gary Coffman wrote: On Wed, 30 Jun 2004 14:53:00 -0400, Yuri Kuchinsky wrote: Gary Coffman wrote: [snip] The apparent fact that the Native Americans *didn't* cast native copper This is a "fact" only if you disregard all evidence to the contrary, as you appear to be doing. Virtually all of the evidence presented to date in this thread is against casting of ancient Michigan native copper artifacts. If you have conclusive evidence showing characteristic porosity in all the items claimed to be cast, if you have evidence showing a chemical analysis of true alloying between the native copper and other metals (mainly silver) found with it in the halfbreed ore matrix, if you have evidence of large numbers of identically dimensioned artifacts representative of a casting provenance, etc, then present it. Otherwise you have no case. You cannot claim "you have no case" UNLESS you prove there is no "true alloying between the native copper and other metals" and that takes an analysis of the metals in the artefacts found. It works both ways you know. Actually, I can make the claim, because heavily alloyed copper is no longer native copper. You are assuming that ALL native copper is of high purity. In fact much Michigan copper ore is smelted to remove impurities. See http://www.usdoj.gov/opa/pr/Pre_96/J...95/58.txt.html What we do know is that ancient Michigan artifacts have been found with silver inclusions. That precludes the possibility that they were ever melted. No, it precludes that item from having been melted only. You cannot extrapolate that beyond the artefact itself. It is a conclusive indication for any case where silver inclusions are found. We do know that of the artifacts which have been put forward as evidence of copper casting, all but one do *not* show the characteristic porosity of atmospheric melting of copper, and that one does not appear to be a deliberate casting. We see TWO artefacts being claimed as being cast - one being conceded as being cast. We don't know the composition of the metal of the second artefact to be able to discard it as "not cast". Neither Tom or I have conceded R666 was cast. We've agreed it shows all the characteristic signs of atmospheric melting, but it doesn't automatically follow that it was deliberately cast. You have claimed it is the sign of "copper" being overheated - ie to melting point else bubbles cannot form. At the same time you have also stated the heat source has to be forced air type to get it hot enough to melt copper. Copper does not need to be heated to melting for blisters to form. Please go back and reread Neubauer for examples of native copper which blistered on annealing *without* being raised to melting temperature. You can blow bubbles in bubble gum without melting it, you can do the same in copper. It merely has to reach a sufficient state of plasticity for the gas pressure from inclusions to deform it into a blister. I see those two statements as being inconsistent with each other. If the Copper was simply hammered and annealed, the temp should NOT be able to get high enough to cause any bubbling. Well, then you're wrong. Gary Eric Stevens |
Copper Casting In America (Trevelyan)
Seppo Renfors wrote in message ... "Paul K. Dickman" wrote: In order to illustrate the nature of the porosity in melted copper I put a few pictures up. http://tinyurl.com/3cw7p Very interesting! The first labeled Casting is a small ingot cast of ca110 copper It started out ........ The size of this is indicative of how much gas was dissolved in the metal. It is approximately 10% of the original volume of the ingot. Essentially what you are saying is that a lot of the gases escaped before it solidified. Possibly, probably. But more importantly, there is still an volume of gas bubbles trapped inside the ingot, that is equivalent to the volume of the blob sticking out of the upper left hand side. The third picture, labeled forgings, shows it's workability. The lower shot is from the pure copper ingot, You can see it is full of fractures and tears. I assume this is from the melted copper described above? Yes Are you suggesting the "tears" are the result of (A) the pure copper having been melted (B) because it is pure copper? They are a result of the small air bubbles trapped throughout the metal caused by melting it in less than controlled conditions. Pure copper, direct from the mill, melted in a vacuum furnace, or a void and inclusion free piece of native copper, would forge out as well as the upper alloyed sample. If (A) how does it compare to not melted copper of equal grade? Would it not also depend on the handling of the material if it tears or not - eg more frequent annealing - hot working etc? I have added a 4th picture to the above mentioned url to address this. It is of a forging made from manufactured bar. In fact it is made from the same bar that made up most of the cast piece. The cast piece was annealed 8 to 10 times in the course of it's forging. That is a lot, considering it's length was only increased by 50%. But the large crack on right the appeared in the first round of hammering and I didn't want the piece to fall apart. The piece made from manufactured copper was annealed twice. I probably could have done the forging with out annealing at all, but it was a small piece being held in my fingers. As the hammering hardens the metal, more vibrations travel up the metal and into the hand. It can be quite painful. If it is from the melted ingot - what has happened to the "myriad of amorphous blobs" - they are no longer visible. For the sake of orientation, the sectioned surface of the ingot is the small end of the forging. The outer surface of the casting solidifies very rapidly, and is usually bubble free, the bubbles tend to be trapped inside. Subsequent forging would mash these shut (although not bond them together) making them difficult to see in a radiograph as they would either be smaller than the resolution or look like regular forging flaws. This is why radiographs are inconclusive an any piece that may have been forged. The two metals are visually identical, but one casts like crap and the other doesn't. If something is acceptable or not, depends on the use and views of acceptability on the day. If something was melted to get a single lump, to be later beaten into a sheet for further working to jewellery for instance, then perhaps it really doesn't matter - perhaps it may no longer even be obvious to have been cast. This is true, but as cast copper is as soft as it can be and needs a significant amount of hammering to harden it. For any edged tools or fish hooks or awls, this would surely display the tendency to fracture. Sheet goods also would require a lot of hammering. Heavier decorative items or ceremonial pieces would require much less work and cast preforms would work fine. If they were casting on any scale, it is not just inevitable that alloying occurs, it is pretty much a necessity. I doubt there was any real high volume of casting occurring, considering other sources. However the lack of scraps and off cuts note, as well as the storing of off cuts in a bag with other copper artefacts and a sheet of copper indicates scraps were used up. If you want to prove casting, stop stroking around with radiographs and look for alloying. Well..... there is the problem. This information hasn't been gathered of either kind to any extent to my knowledge. The radiography (or analysis) of two items... or even a dozen items, is not representative of the tens of thousands of artefacts found. Yes, that appears to be the rub. And is an area in which someone should undertake some real hands on research. Otherwise, it is like the old saw about the man who lost his keys late one dark night. He spent the rest of the night looking for them beneath the only street light that he passed, because if he lost them anywhere else, he wouldn't be able to find them in the dark. Paul K. Dickman |
Copper Casting In America (Trevelyan)
Seppo Renfors wrote in message ... I already said it was brazing. I couldn't think of the specific decoration name before, but it is used in making "mokume gane" as found, and originating on samurai sword handles from about 1600 - 1800. Actually, Mokume Gane is not a brazing process, but a diffusion bonding process similar to forge welding. It occured well below the melting point of all the alloys involved. I cannot speak to the state of the science now, but back in the late 70's, when I was doing research on it in college, our theory was this. At elevated temperatures the grain structure of the metal undergoes enormous changes (this is what causes annealing) as the grains grow they can grow between separate but closely associated pieces of metal, Assuming that the junction is chemically clean and free from oxides. Are you suggesting silver "sweats" (forms liquid beads) way below its melting point? Actually it can. metals alloyed together have an Gestalt proportion called the eutectic. In the case of silver and copper it melts at a lower temperature then either. But the term sweats as it applys to Mokume gane is kind of a misnomer. It comes from the amount of blacksmiths we had on the project. It was a term they used in forge welding iron, and refered to the surface geting a greasy or oily appearance as the welding temperature is acheived. For Mokume, the rule of thumb that we used was that this temperature was roughly 2/3 of the eutectic temperature of the alloys involved. Paul K. Dickman |
Copper Casting In America (Trevelyan)
Eric Stevens wrote:
On Sat, 03 Jul 2004 04:54:31 -0400, Gary Coffman wrote: snip Actually, I can make the claim, because heavily alloyed copper is no longer native copper. You are assuming that ALL native copper is of high purity. In fact much Michigan copper ore is smelted to remove impurities. See http://www.usdoj.gov/opa/pr/Pre_96/J...95/58.txt.html Eric, My understanding is that 'native copper' is a term meaning 'pure copper' (well over 99% pure as found), and not a reference either to copper 'native' to, say, the Keewenaw Peninsula of the Upper Peninsula of Michigan, or to copper used by 'native' peoples. By that definition, copper that needs smelting is not 'native' copper. Sort of like 'meteoric', init? Tom McDonald snip |
Copper Casting In America (Trevelyan)
Eric Stevens wrote:
On Sat, 03 Jul 2004 01:38:33 -0500, Tom McDonald wrote: snip I'd appreciate any thoughts you have on contacting folks about this. Wasn't there some small museum that might have received Mallery's papers after his death? Only if you call the Smithsonian small. :-) My contact there did confirm that they once had them. Eric, I thought I recalled that they may have been given, perhaps by the Smithsonian, to a much smaller museum. Kelley Museum? Something like that. Or I could be conflating two stories. Tom McDonald snip |
Copper Casting In America (Trevelyan)
On Sat, 03 Jul 2004 12:37:13 -0500, Tom McDonald
wrote: Eric Stevens wrote: On Sat, 03 Jul 2004 01:38:33 -0500, Tom McDonald wrote: snip I'd appreciate any thoughts you have on contacting folks about this. Wasn't there some small museum that might have received Mallery's papers after his death? Only if you call the Smithsonian small. :-) My contact there did confirm that they once had them. Eric, I thought I recalled that they may have been given, perhaps by the Smithsonian, to a much smaller museum. Kelley Museum? Something like that. My recollection is that they were given to a repository for archives. Or I could be conflating two stories. Tom McDonald snip Eric Stevens |
Copper Casting In America (Trevelyan)
On Fri, 2 Jul 2004 18:09:16 -0500, "Paul K. Dickman"
wrote: In order to illustrate the nature of the porosity in melted copper I put a few pictures up. http://tinyurl.com/3cw7p The first labeled Casting is a small ingot cast of ca110 copper It started out essentially 99.9% fine. The casting method was about as simple as you can get. It was melted with an oxy-acetylene torch and poured into an open mold, made by scraping a depression into some foundry sand. The "cocks comb" sticking out in the upper left is not a sprue. When the pour was finished the ingot was shaped like a little loaf. As it solidified, dissolved gasses came out of solution with the metal. As they did they were trapped by the solidified metal on the outside of the ingot and built up pressure. Eventually a weaker spot in the surface of the metal gave way and metal and gas squirted out. Like stepping on a ketchup packet in the McDonalds parking lot. The size of this is indicative of how much gas was dissolved in the metal. It is approximately 10% of the original volume of the ingot. Measured at what temperature and pressure? The rough area in the lower left is not indicative of porosity, It is where the metal first struck the sand. When it did, it's surface tension was sufficiently disturbed to allow it to flow into the spaces between the sand grains. The second picture, labeled section, shows what this looked in a cross section cut at about the base of the "cocks comb" You can easily see the large bubbles. It also has a large amount of small bubbles that are visible under a 10 power loupe. You can see that it looks very similar to the R666 radiograph. However that piece looks more like a mistake than a deliberate casting. You can also see that it is not a single round bubble but a miriad of amorphous blobs. The third picture, labeled forgings, shows it's workability. The lower shot is from the pure copper ingot, You can see it is full of fractures and tears. The upper forging is made from an ingot cast from approx. 4% silver-96% copper. This ingot exhibited no cocks comb and the forging was made from the entire ingot, with no waste removed. The two metals are visually identical, but one casts like crap and the other doesn't. If they were casting on any scale, it is not just inevitable that alloying occurs, it is pretty much a necessity. If you want to prove casting, stop stroking around with radiographs and look for alloying. Paul K. Dickman Eric Stevens |
Copper Casting In America (Trevelyan)
On Sat, 03 Jul 2004 12:34:37 -0500, Tom McDonald
wrote: Eric Stevens wrote: On Sat, 03 Jul 2004 04:54:31 -0400, Gary Coffman wrote: snip Actually, I can make the claim, because heavily alloyed copper is no longer native copper. You are assuming that ALL native copper is of high purity. In fact much Michigan copper ore is smelted to remove impurities. See http://www.usdoj.gov/opa/pr/Pre_96/J...95/58.txt.html Eric, My understanding is that 'native copper' is a term meaning 'pure copper' (well over 99% pure as found), and not a reference either to copper 'native' to, say, the Keewenaw Peninsula of the Upper Peninsula of Michigan, or to copper used by 'native' peoples. By that definition, copper that needs smelting is not 'native' copper. The point is we are discussing the possibility that some native copper may have been s/melted. Putting a fence around the definition of 'native copper' means that we have to find another word for copper s/melted by the natives. That all native copper is pure is merely an assumption. Sort of like 'meteoric', init? Although some object to it. 'meteoric' is a precise description of the type of copper used by North American natives to make many (if not all) of their known artifacts. There is no absolute reason why the natives should not have used other sources of copper. Tom McDonald snip Eric Stevens |
Copper Casting In America (Trevelyan)
Eric Stevens wrote in message ... On Fri, 2 Jul 2004 18:09:16 -0500, "Paul K. Dickman" wrote: In order to illustrate the nature of the porosity in melted copper I put a few pictures up. http://tinyurl.com/3cw7p The first labeled Casting is a small ingot cast of ca110 copper It started out ......... parking lot. The size of this is indicative of how much gas was dissolved in the metal. It is approximately 10% of the original volume of the ingot. Measured at what temperature and pressure? Eyeballed mostly. Once the outside of the ingot has chilled an ingot this small shrinks pretty minimally. The cocks comb consists entirely of metal and gas that used to be inside the ingot but was expelled by the gas inside the ingot. The cocks comb is roughly 10% of the size of the ingot minus the cocks comb. Paul K. Dickman |
Copper Casting In America (Trevelyan)
Eric Stevens wrote: On Sat, 03 Jul 2004 07:38:25 GMT, Seppo Renfors wrote: Eric Stevens wrote: On Fri, 02 Jul 2004 13:37:36 GMT, Seppo Renfors wrote: [..] However if one considers that "bubbling" has been claimed to be caused by "overheating" in a annealing process - then it is saying "melted" at the same time, as it cannot bubble UNLESS a portion of it is melted. Also "welding" requires the melting of the metal - or so goddamned close to it that the friction heat generated by a blow on it does melt the metal. Reasonably pure copper can be welded at ambient temperatures merely by pressure. MIllions of electrical connections rely on this property. Anything can be welded at virtually any temperature by using pressure. The Mini Minor crown wheel for the diff started off as a steel disc cut off from a round billet. This was placed on a mould at the end of a hydraulic ram, and the other half of the mould was on another hydraulic ram. To form the crown wheel they were slammed together under huge pressure - it made a very nice crown wheel - and fast! You are confusing forging with welding. Actually I referred to neither. I referred to the use of pressure only as "merely by pressure" was your point. -- SIR - Philosopher unauthorised ----------------------------------------------------------------- The one who is educated from the wrong books is not educated, he is misled. ----------------------------------------------------------------- |
Copper Casting In America (Trevelyan)
Eric Stevens wrote:
On Sat, 03 Jul 2004 12:34:37 -0500, Tom McDonald wrote: Eric Stevens wrote: On Sat, 03 Jul 2004 04:54:31 -0400, Gary Coffman wrote: snip Actually, I can make the claim, because heavily alloyed copper is no longer native copper. You are assuming that ALL native copper is of high purity. In fact much Michigan copper ore is smelted to remove impurities. See http://www.usdoj.gov/opa/pr/Pre_96/J...95/58.txt.html Eric, My understanding is that 'native copper' is a term meaning 'pure copper' (well over 99% pure as found), and not a reference either to copper 'native' to, say, the Keewenaw Peninsula of the Upper Peninsula of Michigan, or to copper used by 'native' peoples. By that definition, copper that needs smelting is not 'native' copper. The point is we are discussing the possibility that some native copper may have been s/melted. Putting a fence around the definition of 'native copper' means that we have to find another word for copper s/melted by the natives. That all native copper is pure is merely an assumption. Eric, No, it is not merely an assumption; it is a definition. There was copper ore that was not pure. It would be called 'copper ore', or other names (halfbreed, etc.) specific to the type of ore body present. I think it useful to use the terms by which the metal and its compounds are known in the area we are discussing. I don't think it is useful to use the construct s/melted. Melting can occur without smelting, in native or drift copper that is already pure. Smelting is necessary early step in a process to extract copper from ore. Melting may or may not happen later in the process. Perhaps I'm over-sensitive about s/melt just now. Seppo has been playing silly buggers with that term, and it raises my hackles a bit. Still, I think it useful to use the terms separately. Tom McDonald |
Copper Casting In America (Trevelyan)
Gary Coffman wrote: On Fri, 02 Jul 2004 13:37:36 GMT, Seppo Renfors wrote: Tom McDonald wrote: Seppo Renfors wrote: Gary Coffman wrote: On Tue, 29 Jun 2004 05:48:01 GMT, Seppo Renfors wrote: Gary Coffman wrote: [..] Again, porosity is the problem, and that should show up on radiographs, as it does for R666 (which certainly shows evidence of being melted in atmosphere, though not necessarily evidence of being cast), but none of the other artifacts presented show that sort of porosity. See: http://www.iwaynet.net/~wdc/copper.htm The 4th and 5th pictures down. Those pictures do not show any evidence of the characteristic porosity copper casting would produce. They disagree with you as it states "The casting bubble can clearly been seen...." Gary showed that the porosity typical of pure cast copper is not present in that artifact. He even explained in just below. Please point out the "porosity" in this sample: Two copper pigs: http://people.uncw.edu/simmonss/P6030052.JPG The evidence of porosity is available to the naked eye in that thin copper flake. There are dozens of tiny bubbles in evidence, You don't even need a radiograph to see them. A radiograph or a density test would settle the matter absolutely, but neither is really needed here as the sizes and numbers of bubbles already visible are clear indications of atmospheric melting. I don't actually SEE any bubbles at all in the pigs, not even when magnified to its largest extent - where 1 cm = 3.5 cm on screen. The casting is obvious in this: http://people.uncw.edu/simmonss/LA_1240-1.4.jpg The large numbers of tiny pits in that piece are suggestive of porosity, but a stereo radiograph, or a density measurement, would be required to determine if the piece is actually riddled with porosity, or if we're just seeing corrosion pitting of otherwise sound copper (if the object is indeed copper, and not a bronze alloy). Now in this item I can definitely see "holes" that you call "porosity" - and you have difficulty accepting it as cast - despite it clearly displaying the shape a mould. I would even suggest that this metal was well overheated when it was cast from the pure look of it. Both pictures show melted copper - pre Colombian melted copper! It leaves Gary's statements hanging in the air. Pre-Columbian, or Spanish Conquest? I don't see a precise dating associated with the individual objects. The web site says the collection of objects date from the Post Classic and Spanish colonial periods. Also, the web site says the objects are a mix of copper, copper-tin bronze, and copper-arsenic bronze. What evidence do you have that the two particular objects you selected from that collection are pure copper rather than bronze? The items are pre-Columbian from around 1300 AD. They are described as "Two copper pigs". I accept their view of it being copper. However if one considers that "bubbling" has been claimed to be caused by "overheating" in a annealing process - then it is saying "melted" at the same time, as it cannot bubble UNLESS a portion of it is melted. Also "welding" requires the melting of the metal - or so goddamned close to it that the friction heat generated by a blow on it does melt the metal. You're wrong on both counts. Copper is a malleable, ie plastic, material even at room temperature. It is malleable in relation to granite but then so is steel.... At annealing temperature (500F or greater) it is much more so. Fahrenheit is a long ago discarded temperature measure here and it is fairly meaningless to me - however the 500F appears to be a temperature people use to bake cakes or roast a leg of lamb in a standard domestic oven. I don't even see the copper glowing red from heat at that point. Naturally annealing can be done at almost any temperature, but from other things I have read, much much higher temperatures are in fact used before the term "annealing" is applied to it. Eg go get the metal red hot. But one thing that does puzzle me in this claim of yours. A piece of pure copper, as a result of bringing it up to baking temperature can cause "bubbles" - forget the baking, take it to dark red state to form "bubbles". From what does the "bubble" form, we are talking about pure copper here? How did (whatever) get INTO the copper to form a bubble in the first place? Bubble gum need not be molten for bubbles to be formed in it, neither does copper. Totally irrelevant. But you do point to an external source for the bubbles by that example - so how does it actually get INTO the copper in the first place if it isn't (partially) melted? And while copper can be welded, in an inert atmosphere, by melting, it can also be welded at lower temperature by pressure. No it can't. "Pressure" in itself does almost nothing. A loaded freight train running over a "copper" coin only flattens it and does nothing else. It is the sudden impact pressure that causes the molecules to move rapidly, that causes FRICTION, which in turn causes heat and if sufficient sudden pressure is applied (eg hammer blow to already hot metal) it CAN melt the material. To "weld" something by definition requires bringing part of it to a liquid state - ie melted in the portion being welded. WELD - verb [with obj.], join together (metal pieces or parts) by heating the surfaces to the point of melting with a blowpipe, electric arc, or other means, and uniting them by pressing, hammering, etc - OED. Though I note that "metals" isn't the only things welded - plastic is also welded, but the rest applies just the same. It also reminds me of an axle being welded onto the wheel mounting flange. The axle is placed against the flange with pressure, and spun very fast. When suitably hot, the rotation was stopped, added pressure was applied, the axle was pushed in on the flange by about 1 cm, this to weld it. This melted the material in the joint part as well as expanded the contact area. Those are two logical examples of melting occurring - the knowledge of melting copper existed. It beggars belief that scraps and off cuts were NOT melted when the process must have been known to them. That people suggest they would rather go and do hard manual labour another day to find a piece "just right" for the job, when it is right there, right now, right before them. All they have to do is melt it into one lump. And wind up with a porous lump of no use to anyone. Really, you haven't absorbed anything anyone has been telling you about the atmospheric casting of pure copper. The evidence exists that casting was used - Eric Stevens has provided expert testament to that effect. I have pointed to actual evidence (such as exists) including in this post. You label cast copper as "of no use to anyone" when it obviously was of use. You are probably very right in everything you say -for today's use when high quality melted copper can he had - but that isn't the issue at all. Frankly, if you find it "useless" in your endeavours is irrelevant, it doesn't mean the ancients did. YOU are not them. The implied suggestion they would rather do the hard labour, and not proceed with the easier option available immediately to them, isn't consistent with known human behaviour. That's your interpretation. But since your interpretation is wrong, your conclusion is also wrong. You are very quick at labelling "wrong" without a single shred of proof or alternate theory! I therefor totally reject such unsubstantiated claims as worthless. -- SIR - Philosopher unauthorised ----------------------------------------------------------------- The one who is educated from the wrong books is not educated, he is misled. ----------------------------------------------------------------- |
Copper Casting In America (Trevelyan)
Eric Stevens wrote: On Sat, 03 Jul 2004 01:29:01 GMT, Seppo Renfors wrote: Eric Stevens wrote: On Fri, 02 Jul 2004 06:02:01 GMT, Seppo Renfors wrote: Gary Coffman wrote: On Thu, 01 Jul 2004 08:26:52 GMT, Seppo Renfors wrote: Gary Coffman wrote: On Tue, 29 Jun 2004 05:48:01 GMT, Seppo Renfors wrote: Gary Coffman wrote: [..] Again, porosity is the problem, and that should show up on radiographs, as it does for R666 (which certainly shows evidence of being melted in atmosphere, though not necessarily evidence of being cast), but none of the other artifacts presented show that sort of porosity. See: http://www.iwaynet.net/~wdc/copper.htm The 4th and 5th pictures down. Those pictures do not show any evidence of the characteristic porosity copper casting would produce. They disagree with you as it states "The casting bubble can clearly been seen...." And as I note below, they are quite wrong. It is rather obvious that they have little practical experience or knowledge about working native copper. It behaves significantly differently from other metals when melted or cast. Copper is copper no matter what part of the world it is in. ALLOYS vary from place to place. So I find it hard to accept Michigan "native copper" is much different from that here in Australia. Michigan native copper is 'meteoric' copper. I really hate these poncy misleading terms like "meteoric" copper and "native" copper when perfectly good clear terms are available to use like "pure", "nugget", "vein"...... Hmmmm.... does that then meant that "meteoric iron" isn't really "meteoric" or extraterrestrial at all? Australia does have some meteoric copper (see http://www.econs.ecel.uwa.edu.au/AMH...ett/news21.htm) but it is accessible in quantitities very much smaller than in NA. Yes, this is virtually my "back yard". There has been copper mining all along the Flinders Ranges, from North to South as well as on York Peninsular (Moonta - Wallaroo - Kadina districts, the "copper triangle"). But the Michigan copper and, presumably, the Balfour meteoric copper is of an unusually high purity. It is indeed that. -- SIR - Philosopher unauthorised ----------------------------------------------------------------- The one who is educated from the wrong books is not educated, he is misled. ----------------------------------------------------------------- |
Copper Casting In America (Trevelyan)
Eric Stevens wrote: On Sat, 03 Jul 2004 04:12:21 GMT, Philip Deitiker wrote: [..] And what I demonstrated was that casting was not the primary form of copper tool formation. IOW I am discrediting Mallory's claim by questioning whether casting was used for tools as ubiguitously as believed or was it for more experimental or recreational activities. The tool manufactoring industry in mesoamerica is no secret, what appears to be is the use of casting in that industry. A question by you is sufficient to discredit something? Gee! You must be important! Well...... he did as God to get out of his chair.... if that is any indication... -- SIR - Philosopher unauthorised ----------------------------------------------------------------- The one who is educated from the wrong books is not educated, he is misled. ----------------------------------------------------------------- |
Copper Casting In America (Trevelyan)
On Sun, 04 Jul 2004 01:02:50 GMT, Seppo Renfors
wrote: Eric Stevens wrote: On Sat, 03 Jul 2004 07:38:25 GMT, Seppo Renfors wrote: Eric Stevens wrote: On Fri, 02 Jul 2004 13:37:36 GMT, Seppo Renfors wrote: [..] However if one considers that "bubbling" has been claimed to be caused by "overheating" in a annealing process - then it is saying "melted" at the same time, as it cannot bubble UNLESS a portion of it is melted. Also "welding" requires the melting of the metal - or so goddamned close to it that the friction heat generated by a blow on it does melt the metal. Reasonably pure copper can be welded at ambient temperatures merely by pressure. MIllions of electrical connections rely on this property. Anything can be welded at virtually any temperature by using pressure. The Mini Minor crown wheel for the diff started off as a steel disc cut off from a round billet. This was placed on a mould at the end of a hydraulic ram, and the other half of the mould was on another hydraulic ram. To form the crown wheel they were slammed together under huge pressure - it made a very nice crown wheel - and fast! You are confusing forging with welding. Actually I referred to neither. I referred to the use of pressure only as "merely by pressure" was your point. You say it started off as a steel disc. You have not mentioned two pieces which were welded together. http://www.forging.org/Design/pg6_9.html describes the manufacture of gears using a similar process to that used for the Mini. Eric Stevens |
Copper Casting In America (Trevelyan)
On Sun, 04 Jul 2004 02:36:09 GMT, Seppo Renfors
wrote: ---- snip ---- And while copper can be welded, in an inert atmosphere, by melting, it can also be welded at lower temperature by pressure. You are wrong, particularly in the case of copper. The power in your house comes to through a large number of cold welds formed merely by pressure. This is true irrespective of whether you are supplied via copper or aluminium cables. No it can't. "Pressure" in itself does almost nothing. A loaded freight train running over a "copper" coin only flattens it and does nothing else. It is the sudden impact pressure that causes the molecules to move rapidly, that causes FRICTION, which in turn causes heat and if sufficient sudden pressure is applied (eg hammer blow to already hot metal) it CAN melt the material. To "weld" something by definition requires bringing part of it to a liquid state - ie melted in the portion being welded. How do you explain the well known welding at ambient temperatures of precision slip-gauges made of hardened steel? Leave them in contact overnight and you will be lucky to get them apart in the morning. --- snip --- Eric Stevens |
Copper Casting In America (Trevelyan)
On Sat, 03 Jul 2004 20:12:58 -0500, Tom McDonald
wrote: Eric Stevens wrote: On Sat, 03 Jul 2004 12:34:37 -0500, Tom McDonald wrote: Eric Stevens wrote: On Sat, 03 Jul 2004 04:54:31 -0400, Gary Coffman wrote: snip Actually, I can make the claim, because heavily alloyed copper is no longer native copper. You are assuming that ALL native copper is of high purity. In fact much Michigan copper ore is smelted to remove impurities. See http://www.usdoj.gov/opa/pr/Pre_96/J...95/58.txt.html Eric, My understanding is that 'native copper' is a term meaning 'pure copper' (well over 99% pure as found), and not a reference either to copper 'native' to, say, the Keewenaw Peninsula of the Upper Peninsula of Michigan, or to copper used by 'native' peoples. By that definition, copper that needs smelting is not 'native' copper. The point is we are discussing the possibility that some native copper may have been s/melted. Putting a fence around the definition of 'native copper' means that we have to find another word for copper s/melted by the natives. That all native copper is pure is merely an assumption. Eric, No, it is not merely an assumption; it is a definition. Please point me to a source. There was copper ore that was not pure. It would be called 'copper ore', or other names (halfbreed, etc.) specific to the type of ore body present. I think it useful to use the terms by which the metal and its compounds are known in the area we are discussing. I don't think it is useful to use the construct s/melted. Melting can occur without smelting, in native or drift copper that is already pure. Smelting is necessary early step in a process to extract copper from ore. Melting may or may not happen later in the process. Perhaps I'm over-sensitive about s/melt just now. Seppo has been playing silly buggers with that term, and it raises my hackles a bit. Still, I think it useful to use the terms separately. Tom McDonald Eric Stevens |
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