Home |
Search |
Today's Posts |
|
Woodworking (rec.woodworking) Discussion forum covering all aspects of working with wood. All levels of expertise are encouraged to particiapte. |
Reply |
|
LinkBack | Thread Tools | Display Modes |
#1
Posted to rec.woodworking
|
|||
|
|||
Potassium Dichromate
I recently scored some pattern-grade Honduras Mahogany and have a couple of
projects planned. Not being a "stain everything and slather it with poly" guy, I wanted to try potassium dichromate. In a word... holy cow. OK that's two words. I mixed a very weak solution and tried it on some mahogany scraps and also some cherry. I got the expected results with the mahogany, but the cherry astounded me! With one application on the cherry the wood turned a deep dark brown... not a color I'd like on a cherry piece typically, but for matching older cherry pieces this may be just the trick. So the question is: Have any of the wood dorkers out there had the same experience as me? How about other woods? Don |
#2
Posted to rec.woodworking
|
|||
|
|||
Potassium Dichromate
Where did you get the potassium dichromate?? What other names might
it come under? Pete On Fri, 07 Apr 2006 13:46:43 GMT, "Don Sforza" wrote: I recently scored some pattern-grade Honduras Mahogany and have a couple of projects planned. Not being a "stain everything and slather it with poly" guy, I wanted to try potassium dichromate. In a word... holy cow. OK that's two words. I mixed a very weak solution and tried it on some mahogany scraps and also some cherry. I got the expected results with the mahogany, but the cherry astounded me! With one application on the cherry the wood turned a deep dark brown... not a color I'd like on a cherry piece typically, but for matching older cherry pieces this may be just the trick. So the question is: Have any of the wood dorkers out there had the same experience as me? How about other woods? Don |
#3
Posted to rec.woodworking
|
|||
|
|||
Potassium Dichromate
|
#4
Posted to rec.woodworking
|
|||
|
|||
Potassium Dichromate
Through yahoo shopping
http://www.2spi.com/catalog/chem/chem2a4.shtml wrote in message ... Where did you get the potassium dichromate?? What other names might it come under? Pete |
#6
Posted to rec.woodworking
|
|||
|
|||
Potassium Dichromate
If you get a relatively cheap wood to become black in the future would you
make a post of it for me. ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
#7
Posted to rec.woodworking
|
|||
|
|||
Potassium Dichromate
bent wrote: If you get a relatively cheap wood to become black in the future would you make a post of it for me. Burn it. I use a heavy duty propane torch designed to burn brush. Nice big round flame makes it pretty easy to scorch it evenly. India ink. Aniline dye and black pigmented stain. JP |
#8
Posted to rec.woodworking
|
|||
|
|||
Potassium Dichromate
|
#9
Posted to rec.woodworking
|
|||
|
|||
Potassium Dichromate
Joe wrote: You might be confusing this with another potassium compound. I assume he refers to K2Cr2O7 which is useful in photographic processing among other uses, and, as a matter of fact, is the active ingredient in an over-the-counter headache remedy...cannot remember the name. Basically it is an oxidizer. Not correct at all. Read the MSDS on potassium dichromate. Toxic as all hell, and a very well-known carcinogen. |
#11
Posted to rec.woodworking
|
|||
|
|||
Potassium Dichromate
|
#12
Posted to rec.woodworking
|
|||
|
|||
Potassium Dichromate
wrote:
wrote: Joe wrote: You might be confusing this with another potassium compound. I assume he refers to K2Cr2O7 which is useful in photographic processing among other uses, and, as a matter of fact, is the active ingredient in an over-the-counter headache remedy...cannot remember the name. Basically it is an oxidizer. Not correct at all. Read the MSDS on potassium dichromate. Toxic as all hell, and a very well-known carcinogen. Trivalent chromium is an essential nutrient and might be found in a headache medecine. Hexavalent chromium is quite toxic but fortunately, poorly absorbed via the digestive track (due to the pH of stomache acid) for most people. Inhalation of the dust is another matter. There's a wide range of pH levels along the gut. Metals pass through the lining via mechanisms for which there is, very likely for any heavily oxidized form of chromium, no specific one. Neither is there one in the lungs, but there's also less protective glycoproteins or proteoglycans, and less transient flotsam lying about for the ion to bind with or associate with, no flora that might have an interest in it, and there's no exit if the cilia can't beat it out. I'm just guessing though, and I could be wrong. er -- email not valid |
#13
Posted to rec.woodworking
|
|||
|
|||
Potassium Dichromate
"Joe" wrote in message
... On 7 Apr 2006 08:47:26 -0700, wrote: Don Sforza wrote: I recently scored some pattern-grade Honduras Mahogany and have a couple of projects planned. Not being a "stain everything and slather it with poly" guy, I wanted to try potassium dichromate. In a word... holy cow. OK that's two words. A word (or a few) of caution. Potassium dichromate is a powerful human carcinogen and a strong oxidizer. For the former reason it has almost entirely been phased out of industrial uses. You might be confusing this with another potassium compound. I assume he refers to K2Cr2O7 which is useful in photographic processing among other uses, and, as a matter of fact, is the active ingredient in an over-the-counter headache remedy...cannot remember the name. Basically it is an oxidizer. It is probably illegal to dispose of it by pouring it down the drain. Though you are not likely to get prosecuted, that is really not the point. Probably it would be prudent to do a little reasearch and find a way to treat it to make it safer for disposal. That _may_ be as simple as mixing it with portland cement and then throwing the solid chunk into the garbage. Perhaps a real chemist can comment further. I read, in a book on router techniques, of a similar process using nitric acid. One wets the wood and then heats it with a heat gun until the desired darkening is achieved, then neutralizes with a sodium bicarbonate (baking soda) solution. That process generates nitrogen dioxide which can be quite deadly, but neutralizing and disposing of the unused solution is quite trivial. As with most of life's hazards, there is no rational reason to be afraid to try these things, one just needs to understand the dangers and how to mitigate them. As a "real" chemist, I can tell you that K2Cr2O7 is potassium bichromate (or dichromate, whichever you prefer). It is a highly corrosive poison. I'd love to know the source of your statement that it is in a headache remedy. Chromium in all it oxidation states has been found to be carcinogenic. It is a matter of its physical form and how you are exposed to it. Please keep in mind that arsenic and selenium are also necessary trace elements. I wouldn't go around eating arsenic and chromium salts by the handful. As for using it to stain wood, there is no reason to do so. These type of things were used long ago before the advent of modern light fast stains. If the old-timers had modern stains, I am sure they would have used them in preference to "chemical" stains. I would be careful about using nitric acid to stain wood. A nationally recognized expert in finishing used some once on a test block of wood. Several years later, he cut through the piece. He was surprised by the extent of penetration and how he could still smell the by-products of the nitric acid. Disposal of nitric acid, while easier than chromate salts, is not trivial. It must be carefully neutralized and the resulting nitrate salts must be dealt with. |
#14
Posted to rec.woodworking
|
|||
|
|||
Potassium Dichromate
Baron wrote:
"Joe" wrote in message ... On 7 Apr 2006 08:47:26 -0700, wrote: Don Sforza wrote: I recently scored some pattern-grade Honduras Mahogany and have a couple of projects planned. Not being a "stain everything and slather it with poly" guy, I wanted to try potassium dichromate. In a word... holy cow. OK that's two words. A word (or a few) of caution. Potassium dichromate is a powerful human carcinogen and a strong oxidizer. For the former reason it has almost entirely been phased out of industrial uses. You might be confusing this with another potassium compound. I assume he refers to K2Cr2O7 which is useful in photographic processing among other uses, and, as a matter of fact, is the active ingredient in an over-the-counter headache remedy...cannot remember the name. Basically it is an oxidizer. It is probably illegal to dispose of it by pouring it down the drain. Though you are not likely to get prosecuted, that is really not the point. Probably it would be prudent to do a little reasearch and find a way to treat it to make it safer for disposal. That _may_ be as simple as mixing it with portland cement and then throwing the solid chunk into the garbage. Perhaps a real chemist can comment further. I read, in a book on router techniques, of a similar process using nitric acid. One wets the wood and then heats it with a heat gun until the desired darkening is achieved, then neutralizes with a sodium bicarbonate (baking soda) solution. That process generates nitrogen dioxide which can be quite deadly, but neutralizing and disposing of the unused solution is quite trivial. As with most of life's hazards, there is no rational reason to be afraid to try these things, one just needs to understand the dangers and how to mitigate them. As a "real" chemist, I can tell you that K2Cr2O7 is potassium bichromate (or dichromate, whichever you prefer). It is a highly corrosive poison. I'd love to know the source of your statement that it is in a headache remedy. Chromium in all it oxidation states has been found to be carcinogenic. It is a matter of its physical form and how you are exposed to it. Please keep in mind that arsenic and selenium are also necessary trace elements. I wouldn't go around eating arsenic and chromium salts by the handful. As for using it to stain wood, there is no reason to do so. These type of things were used long ago before the advent of modern light fast stains. If the old-timers had modern stains, I am sure they would have used them in preference to "chemical" stains. I would be careful about using nitric acid to stain wood. A nationally recognized expert in finishing used some once on a test block of wood. Several years later, he cut through the piece. He was surprised by the extent of penetration and how he could still smell the by-products of the nitric acid. Disposal of nitric acid, while easier than chromate salts, is not trivial. It must be carefully neutralized and the resulting nitrate salts must be dealt with. Must be an old chemist to call in bichromate. Nonetheless I certainly agree with your statements on chromium. Don't agree with your statement on arsenic being an essential trace element. Nitric acid disposal may be a problem but only for industrial use, especially if it is contaminated with dissolved metals which it often is in industry. Nitrates and nitrites are a problem when they leach into groundwater but the problem is mostly from agriculture (excess fertilizers and stock waste). At least in small amounts the natural nitrogen-- nitric--nitrate cycle in the soil will take care of nitric acid. Depending on where you live, soils will quickly neutralize nitric acid, plants will take up the nitrates and soil organisms will change the excess to nitrogen gas. |
#15
Posted to rec.woodworking
|
|||
|
|||
Potassium Dichromate
In article , "George E. Cawthon" wrote:
Must be an old chemist to call in bichromate. Nonetheless I certainly agree with your statements on chromium. Don't agree with your statement on arsenic being an essential trace element. FYI... "... Boron, chromium, manganese, nickel, tin, vanadium, molybdenum, arsenic, lithium, aluminium, strontium, cesium and silicon are regarded as new trace elements in the sense that they have only recently been considered essential in human diets...." http://www.fao.org/docrep/U5900t/u5900t05.htm -- Regards, Doug Miller (alphageek at milmac dot com) It's time to throw all their damned tea in the harbor again. |
#16
Posted to rec.woodworking
|
|||
|
|||
Potassium Dichromate
Doug Miller wrote:
In article , "George E. Cawthon" wrote: Must be an old chemist to call in bichromate. Nonetheless I certainly agree with your statements on chromium. Don't agree with your statement on arsenic being an essential trace element. FYI... "... Boron, chromium, manganese, nickel, tin, vanadium, molybdenum, arsenic, lithium, aluminium, strontium, cesium and silicon are regarded as new trace elements in the sense that they have only recently been considered essential in human diets...." http://www.fao.org/docrep/U5900t/u5900t05.htm I think I'll reserve judgment. That statement doesn't really make sense. An element has either been demonstrated as essential or not. There are several way that is possible, e.g. lack of the element causes a disease or other problem, the element is an integral part of an essential molecule or needed to activate the molecule, etc. "Considered essential" doesn't mean much. I'm not current on the subject, but some of those element mentioned are highly suspect. |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|