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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#1
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Boiling lye water. OT, but..
I come to the Font of Wisdom with an observation and a question. I am boiling down "lye water" filtered through wood ashes in a stainless steel pot. (MWC). Potassium Hydroxide in solution with water of 1.2 S.G. is what I seek. No problem, I have done it many times before. Soap making is the ultimate goal. (historical re-enactment) My question is: Why does the pot on the stove bang, and want to make louder bangs as it comes to a boil? I have to simmer the pot to boil to avoid what seems ...kaboom My guess is S.G. Specific Gravity...but sal****er heavy does not bang like this. ~Dave Red Top Blacksmith |
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On Tue, 25 Jan 2005 17:35:26 -0500, Dave wrote:
I come to the Font of Wisdom with an observation and a question. I am boiling down "lye water" filtered through wood ashes in a stainless steel pot. (MWC). Potassium Hydroxide in solution with water of 1.2 S.G. is what I seek. No problem, I have done it many times before. Soap making is the ultimate goal. (historical re-enactment) My question is: Why does the pot on the stove bang, and want to make louder bangs as it comes to a boil? I have to simmer the pot to boil to avoid what seems ...kaboom The "bangs" are steam bubbles forming and collapsing on the bottom of the pot. Given enough heat input to a pot of cold liguid you can see this effect, regardless of what solution. Reducing the heating rate brings the entire volume of liquid up to the boiling point and stops the collapse of the steam bubbles. -- The instructions said to use Windows 98 or better, so I installed RedHat. |
#3
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I am boiling down "lye water" filtered through wood ashes in a
stainless steel pot. (MWC). Potassium Hydroxide in solution with water of 1.2 S.G. is what I seek. No problem, I have done it many times before. Soap making is the ultimate goal. (historical re-enactment) My question is: Why does the pot on the stove bang, and want to make louder bangs as it comes to a boil? I have to simmer the pot to boil to avoid what seems ...kaboom My guess is S.G. Specific Gravity...but sal****er heavy does not bang like this. Yes, S.G. should be specific gravity. As for the banging, I think you need some nucleation sites to get a nice smooth boil, with lots of small bubbles forming in lots of places, instead of one giant bubble every so often like you get now. Try adding a few small sharp pieces of gravel, say 1/4" diameter. The sharp edges and pockets give nice surfaces for bubbles to form at, which is why chemists call these "boiling stones" :-). Broken unglazed ceramic chips or granite would probably be best. Avoid marble in your lye solution as it will get eaten. -- Regards, Carl Ijames carl.ijames at verizon.net |
#4
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"Carl Ijames" wrote in message news:_kBJd.19098$IP6.4450@trnddc05... I am boiling down "lye water" filtered through wood ashes in a stainless steel pot. (MWC). Potassium Hydroxide in solution with water of 1.2 S.G. is what I seek. No problem, I have done it many times before. Soap making is the ultimate goal. (historical re-enactment) My question is: Why does the pot on the stove bang, and want to make louder bangs as it comes to a boil? I have to simmer the pot to boil to avoid what seems ...kaboom My guess is S.G. Specific Gravity...but sal****er heavy does not bang like this. Yes, S.G. should be specific gravity. As for the banging, I think you need some nucleation sites to get a nice smooth boil, with lots of small bubbles forming in lots of places, instead of one giant bubble every so often like you get now. Try adding a few small sharp pieces of gravel, say 1/4" diameter. The sharp edges and pockets give nice surfaces for bubbles to form at, which is why chemists call these "boiling stones" :-). Broken unglazed ceramic chips or granite would probably be best. Avoid marble in your lye solution as it will get eaten. Sorry to quibble, but marble (and limestone) will not be eaten by lye; lye is alkaline, so is sodium carbonate in all its forms; it will, however, dissolve in an acid solution. Martin -- martindot herewhybrowat herentlworlddot herecom -- Regards, Carl Ijames carl.ijames at verizon.net |
#5
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I'll try the "sharply edged objects" in the pot. Makes sense. I was mostly curious about why the boiling was banging so much with a wood ash lye solution. I assumed as far as that it was steam bubbles forming, and collapsing under the water...but...why? Dense salt water, or dense sugar water does not bang like this, upon bringing to a boil. humble, in the face of new, ~Dave |
#6
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I faintly remember from my chemistry days that alkalai solutions are
more prone to "bumping" than neutral or acidic solutions, but I don't remember why...:-( However, I speculate that it might have to do with the fact that hot alkalai is a very effective cleaner and degreaser; this might tend to remove nucleation centers which facilitate boiling (like dirt and grease) from the pot walls and bottom , and thereby make the formation of sudden, violent steam bubbles more likely. Again, this is pure speculation, just sitting here thinking about it. Regards, Bob |
#7
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Avoid marble in your lye solution as it will get eaten.
Sorry to quibble, but marble (and limestone) will not be eaten by lye; lye is alkaline, so is sodium carbonate in all its forms; it will, however, dissolve in an acid solution. Eaten was a bit of an overstatement; nibbled at would be more correct. Depending upon its source marble ranges from 30-60% calcium carbonate and similar levels of magnesium carbonate which as you say will be basically unaffected. However, marble can also contain up to 10% SiO2 which is etched and dissolved by hot concentrated alkali causing the marble chips to slowly crumble, and up to a few percent Fe (and other metals depending on the coloration) in various oxidation states which will leach out and oxidize to rusty water - none of which I assumed that the original poster would want in his homemade lye. -- Regards, Carl Ijames carl.ijames at verizon.net |
#8
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"Bob" wrote in message
ups.com... I faintly remember from my chemistry days that alkalai solutions are more prone to "bumping" than neutral or acidic solutions, but I don't remember why...:-( However, I speculate that it might have to do with the fact that hot alkalai is a very effective cleaner and degreaser; this might tend to remove nucleation centers which facilitate boiling (like dirt and grease) from the pot walls and bottom , and thereby make the formation of sudden, violent steam bubbles more likely. Again, this is pure speculation, just sitting here thinking about it. Regards, Bob Water does interesting things. Example. You live in the mountains at 2000 meters (6000 feet) You put a cup of tap water in the microwave for a minute. Near boiling. Put the cup on the counter top and add 1 spoonful of instant coffee. You now have a "coffee geyser" QED |
#9
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"Dave" wrote in message
... I come to the Font of Wisdom with an observation and a question. I am boiling down "lye water" filtered through wood ashes in a stainless steel pot. (MWC). Potassium Hydroxide in solution with water of 1.2 S.G. is what I seek. No problem, I have done it many times before. Soap making is the ultimate goal. (historical re-enactment) My question is: Why does the pot on the stove bang, and want to make louder bangs as it comes to a boil? I have to simmer the pot to boil to avoid what seems ...kaboom My guess is S.G. Specific Gravity...but sal****er heavy does not bang like this. I don't know, but this may be of interest to you: I've noticed the same thing when boiling commercial lye, which I do to strip steel parts of oil and grease prior to blueing them. Also, if you take a stainless steel pot and scrub it out hard with an abrasive pad and detergent, and then boil water in it, you'll notice the same phenomenon to a lesser degree. I may be related to the pot being *really* clean, which may relate to nucleation as others have suggested...or maybe not. g -- Ed Huntress |
#10
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On Wed, 26 Jan 2005 12:17:26 -0500, Ed Huntress wrote:
I don't know, but this may be of interest to you: I've noticed the same thing when boiling commercial lye, which I do to strip steel parts of oil and grease prior to blueing them. I hear the same noise when one of my water heaters (electric) comes on, but not the other. I always assumed it was the steam bubbles collapsing as they cooled, but I don't know why it only happens on the one. I may be related to the pot being *really* clean, which may relate to nucleation as others have suggested...or maybe not. g I think it's related to heat, somehow |
#11
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Alcohol boils this way too. Instead of small bubbles you get big
ones. And not as often. So it can surprise you when it boils out of the erlenmeyer flask. And the whole bench catches on fire. And the kid doing the boiling just screams and runs. And you have to put it out because the kid who boiled the alcohol is trying to put her hair out. And you get to do that too. ERS |
#12
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the erlenmeyer flask. And the whole bench catches on fire. And the kid
doing the boiling just screams and runs. And you have to put it out because the kid who boiled the alcohol is trying to put her hair out. And you get to do that too. Damn, Where can I get a fun job like this? chuck |
#13
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#14
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"Tim Williams" wrote in message ... "bw" wrote in message ... Water does interesting things. Example. You live in the mountains at 2000 meters (6000 feet) You put a cup of tap water in the microwave for a minute. Near boiling. Put the cup on the counter top and add 1 spoonful of instant coffee. You now have a "coffee geyser" Can do it at sea level too. Just need distilled water (no impurities) and a clean cup (no impurities). You can superheat it because there are no impurities for bubbles to nucleate on. But drop anything in it, and... Tim Wha-a-a? That must mean our tap water (Sydney) is distilled - and *my* cup is clean? Ha! Yes, this unhappy phenomenon is easy to reproduce - and hurts like Hell! (Once bitten..) -- Jeff R. |
#15
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On Wed, 26 Jan 2005 18:10:56 -0600, the renowned "Tim Williams"
wrote: "Jeff R." wrote in message u... Wha-a-a? That must mean our tap water (Sydney) is distilled - and *my* cup is clean? Ha! May well be. I can't say I've ever had our tap water do anything but boil when it reaches approx. 100°C (I think it's exactly 98C or so at this altitude of 800 feet). Tim If you don't think, but rather measure it as it boils (with a reasonably accurate thermometer), you may be surprised. Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com |
#16
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"Tim Williams" wrote in message ... "Jeff R." wrote in message ... Wha-a-a? That must mean our tap water (Sydney) is distilled - and *my* cup is clean? Ha! May well be. I can't say I've ever had our tap water do anything but boil when it reaches approx. 100°C (I think it's exactly 98C or so at this altitude of 800 feet). Tim It is a fine line between boiling over in the microwave and coming out superheated, ready to explode. I certainly have experienced the latter, with tap water, but don't any more 'cause I always use the kettle now. Don't like exploding cups. -- Jeff r. |
#17
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Me to. I'm in Honolulu and we have hard water. It used to happen in a
microwave with no turntable now I'm wondering if the turntable would shake it enough to prevent superheating. I also supercool water in my freezer about once a week. It's cool watching the crystals spread in the water. Karl "Jeff R." wrote in message ... "Tim Williams" wrote in message ... "bw" wrote in message ... Water does interesting things. Example. You live in the mountains at 2000 meters (6000 feet) You put a cup of tap water in the microwave for a minute. Near boiling. Put the cup on the counter top and add 1 spoonful of instant coffee. You now have a "coffee geyser" Can do it at sea level too. Just need distilled water (no impurities) and a clean cup (no impurities). You can superheat it because there are no impurities for bubbles to nucleate on. But drop anything in it, and... Tim Wha-a-a? That must mean our tap water (Sydney) is distilled - and *my* cup is clean? Ha! Yes, this unhappy phenomenon is easy to reproduce - and hurts like Hell! (Once bitten..) -- Jeff R. |
#18
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"Karl Vorwerk" wrote in message ... Me to. I'm in Honolulu and we have hard water. It used to happen in a microwave with no turntable now I'm wondering if the turntable would shake it enough to prevent superheating. I also supercool water in my freezer about once a week. It's cool watching the crystals spread in the water. Karl Hey! That's my favourite party trick - done with apple cider. Takes about three hours in the freezer, then about 10 seconds to freeze solid when opened. Any more than three hours and it freezes in the bottle. J.R. "Jeff R." wrote in message ... "Tim Williams" wrote in message ... "bw" wrote in message ... Water does interesting things. Example. You live in the mountains at 2000 meters (6000 feet) You put a cup of tap water in the microwave for a minute. Near boiling. Put the cup on the counter top and add 1 spoonful of instant coffee. You now have a "coffee geyser" Can do it at sea level too. Just need distilled water (no impurities) and a clean cup (no impurities). You can superheat it because there are no impurities for bubbles to nucleate on. But drop anything in it, and... Tim Wha-a-a? That must mean our tap water (Sydney) is distilled - and *my* cup is clean? Ha! Yes, this unhappy phenomenon is easy to reproduce - and hurts like Hell! (Once bitten..) -- Jeff R. |
#19
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doing the boiling just screams and runs. And you have to put it out
because the kid who boiled the alcohol is trying to put her hair out. And you get to do that too. Damn, Where can I get a fun job like this? Eighth grade physics class. Gee, I didn't get to take physics in eight grade. They made me take "Earth Science" Or maybe that was in 7th grade. I do know that Physics had to wait until HS. |
#20
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Thanks all for the input. After reading a few replies, in my mind's eye, I visualized a sheet of steam forming and breaking, almost instantaneously, on the bottom of the pot. I drained a bottle of beer, broke the bottle, and placed the bottom in the pot. That works. I can hear the bottle bottom rattling as the lye boils. Nucleation. What would we do without it? ~D |
#21
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Nucleation. What would we do without it?
Drown under the single giant raindrop that a storm would produce? :-) :-) Examine your glass bits after you finish boiling down your lye - I bet you will see the surface starting to haze as the lye slowly dissolves the glass. -- Regards, Carl Ijames carl.ijames at verizon.net |
#22
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Dave wrote: Nucleation. What would we do without it? ~D Note: For members of the White House staff, the word is "new-cue-lation" Joe |
#23
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On Fri, 28 Jan 2005 09:56:04 -0500, the inscrutable Joe
spake: Dave wrote: Nucleation. What would we do without it? ~D Note: For members of the White House staff, the word is "new-cue-lation" Nuke ya later^H^Hion. ================================================== ====== TANSTAAFL: There ain't no such thing as a free lunch. http://diversify.com Gourmet Web Applications ========================== |
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