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#41
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Standard concentration for car battery acid is 32% H2SO4. When mixing
this for preparing a 10% or 1% solution, keep in mind that the density of a solution of 32% is considerably larger than 1.0 gram/ml. Lookup a table for the density at this concentration. When the acid is diluted, I would not bother about lead impurities. Lead sulfate is HIGHLY insoluble in water, and in dilute acid. Only in concentrated H2SO4, lead sulfate is soluble to some extent. When you use sulphuric acid, be careful with it. When sulphuric acid is spilled, it does not evaporate (as opposed to nitric acid and hydrochloric acid). Even low concentration acids can be risky when spilled and left unnoticed. Most of the water evaporates out of the acid and a certain equilibrium concentration of several tens of percents is obtained in the long run. It eats virtually everything, when sufficiently concentrated. Car battery acid is of sufficient concentration to worry about this risk. I sometimes use technical grade sulphuric acid and it works fine for photography purposes. The use of reagent grade (expensive) acid is not necessary. Wilco |
#42
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Standard concentration for car battery acid is 32% H2SO4. When mixing
this for preparing a 10% or 1% solution, keep in mind that the density of a solution of 32% is considerably larger than 1.0 gram/ml. Lookup a table for the density at this concentration. When the acid is diluted, I would not bother about lead impurities. Lead sulfate is HIGHLY insoluble in water, and in dilute acid. Only in concentrated H2SO4, lead sulfate is soluble to some extent. When you use sulphuric acid, be careful with it. When sulphuric acid is spilled, it does not evaporate (as opposed to nitric acid and hydrochloric acid). Even low concentration acids can be risky when spilled and left unnoticed. Most of the water evaporates out of the acid and a certain equilibrium concentration of several tens of percents is obtained in the long run. It eats virtually everything, when sufficiently concentrated. Car battery acid is of sufficient concentration to worry about this risk. I sometimes use technical grade sulphuric acid and it works fine for photography purposes. The use of reagent grade (expensive) acid is not necessary. Wilco |
#44
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In article .com,
wrote: Standard concentration for car battery acid is 32% H2SO4. When mixing this for preparing a 10% or 1% solution, keep in mind that the density of a solution of 32% is considerably larger than 1.0 gram/ml. Lookup a table for the density at this concentration. When the acid is diluted, I would not bother about lead impurities. Lead sulfate is HIGHLY insoluble in water, and in dilute acid. Only in concentrated H2SO4, lead sulfate is soluble to some extent. When you use sulphuric acid, be careful with it. When sulphuric acid is spilled, it does not evaporate (as opposed to nitric acid and hydrochloric acid). Even low concentration acids can be risky when spilled and left unnoticed. Most of the water evaporates out of the acid and a certain equilibrium concentration of several tens of percents is obtained in the long run. It eats virtually everything, when sufficiently concentrated. Car battery acid is of sufficient concentration to worry about this risk. I sometimes use technical grade sulphuric acid and it works fine for photography purposes. The use of reagent grade (expensive) acid is not necessary. Wilco Thanks for that!! -- LF Website @ http://members.verizon.net/~gregoryblank "To announce that there must be no criticism of the President, or that we are to stand by the President, right or wrong, is not only unpatriotic and servile, but is morally treasonable to the American public."--Theodore Roosevelt, May 7, 1918 |
#45
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wrote in message oups.com... Standard concentration for car battery acid is 32% H2SO4. When mixing this for preparing a 10% or 1% solution, keep in mind that the density of a solution of 32% is considerably larger than 1.0 gram/ml. Lookup a table for the density at this concentration. When the acid is diluted, I would not bother about lead impurities. Lead sulfate is HIGHLY insoluble in water, and in dilute acid. Only in concentrated H2SO4, lead sulfate is soluble to some extent. When you use sulphuric acid, be careful with it. When sulphuric acid is spilled, it does not evaporate (as opposed to nitric acid and hydrochloric acid). Even low concentration acids can be risky when spilled and left unnoticed. Most of the water evaporates out of the acid and a certain equilibrium concentration of several tens of percents is obtained in the long run. It eats virtually everything, when sufficiently concentrated. Car battery acid is of sufficient concentration to worry about this risk. I sometimes use technical grade sulphuric acid and it works fine for photography purposes. The use of reagent grade (expensive) acid is not necessary. Wilco I believe that reagent grade chemicals may not actually be any purer than technical or photo grade but comes with an assay showing the impurities and their amounts. High purity chemicals are available but are very expensive. For photography technical grade chemicals are perfectly satisfactory for more purposes. I should have pointed out in my post as you did that the more diluted battery acid can be used in most formulas by simply increasing the amount. Unless it has certain metallic impurities which are specifically injurious to photo processes it should work fine. Lead should make no difference since lead lined containers were standard practice for many years for photo processing. Aluminium, copper, brass, iron, should be avoided. Copper in very small amounts is a prodigeous fogging agent. -- --- Richard Knoppow Los Angeles, CA, USA |
#46
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In article ,
"Richard Knoppow" wrote: I believe that reagent grade chemicals may not actually be any purer than technical or photo grade but comes with an assay showing the impurities and their amounts. High purity chemicals are available but are very expensive. For photography technical grade chemicals are perfectly satisfactory for more purposes. I should have pointed out in my post as you did that the more diluted battery acid can be used in most formulas by simply increasing the amount. Unless it has certain metallic impurities which are specifically injurious to photo processes it should work fine. Lead should make no difference since lead lined containers were standard practice for many years for photo processing. Aluminium, copper, brass, iron, should be avoided. Copper in very small amounts is a prodigeous fogging agent. Interesting, I know the acid did not come from old batteries,... the guy who sold it to me had a large cubey-tainer from which he was filing smaller charging bottles the larger cubey-tainer was factory packaged acid and he told my bottles came from it. -- LF Website @ http://members.verizon.net/~gregoryblank "To announce that there must be no criticism of the President, or that we are to stand by the President, right or wrong, is not only unpatriotic and servile, but is morally treasonable to the American public."--Theodore Roosevelt, May 7, 1918 |
#47
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Gregory W Blank wrote:
In article , "Richard Knoppow" wrote: I believe that reagent grade chemicals may not actually be any purer than technical or photo grade but comes with an assay showing the impurities and their amounts. High purity chemicals are available but are very expensive. For photography technical grade chemicals are perfectly satisfactory for more purposes. I should have pointed out in my post as you did that the more diluted battery acid can be used in most formulas by simply increasing the amount. Unless it has certain metallic impurities which are specifically injurious to photo processes it should work fine. Lead should make no difference since lead lined containers were standard practice for many years for photo processing. Aluminium, copper, brass, iron, should be avoided. Copper in very small amounts is a prodigeous fogging agent. Interesting, I know the acid did not come from old batteries,... the guy who sold it to me had a large cubey-tainer from which he was filing smaller charging bottles the larger cubey-tainer was factory packaged acid and he told my bottles came from it. That's the way battery acid is normally distributed; acid recovered from recycled batteries is disposed of as hazarous waste. It's not the lead; that's relatively easy to precipitate any remaining lead that might be in solution (neutralize with baking soda or chalk, and the lead sulfate will precipitate). It's cadmium, which stays in solution better than lead (cadmium sulfate is about as soluble as silver sulfate, and will remain dissolved at hazarous levels in a neutral solution), and is added to the plates in modern batteries to extend their life. Last time I had battery acid around, it came to me in a small rubbery pouch (I think it was some kind of silicone elastomer, in fact) that was to be used in filling the (dry charged) battery immediately before installation or in the store for rack charging prior to sale. Battery acid obtained in containers, rather than manually drained from a battery by the end user, should be plain technical grade acid diluted with filtered water to working strength (the water is filtered in a manner that specifically removes chlorides, most likely reverse osmosis; chloride ion poisons the reaction that makes a lead-acid battery work). Basic precaution in handling battery acid is to neutralize the working area with baking soda after work is completed -- specifically to prevent evaporative concentration warned of in another thread. Also worthy of note, a tiny drop of battery acid will eat a hole in any cotton cloth that won't show up until the article is laundered and the damaged area crumbles or dissolves in the wash water. It's similarly hazardous to eyes; wear goggles (or, better, a full face shield) as well as the heavy neoprene or nitrile gloves, and preferably a neoprene coated apron as well. Have an eye wash available (a shower works very well for this), and keep a box of baking soda handy. -- The challenge to the photographer is to command the medium, to use whatever current equipment and technology furthers his creative objectives, without sacrificing the ability to make his own decisions. -- Ansel Adams Donald Qualls, aka The Silent Observer http://silent1.home.netcom.com Opinions expressed are my own -- take them for what they're worth and don't expect them to be perfect. |
#48
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Gregory W Blank writes:
"To announce that there must be no criticism of the President, or that we are to stand by the President, right or wrong, is not only unpatriotic and servile, but is morally treasonable to the American public."--Theodore Roosevelt, May 7, 1918 You need to check if it is 35%, or if it is diluted down for filling as is. 35% is diluted before it is used in the batteries, but nowdays they may well be shipping the more dilute read to use conc so as to not confuse the burger flippers. -- Paul Repacholi 1 Crescent Rd., +61 (08) 9257-1001 Kalamunda. West Australia 6076 comp.os.vms,- The Older, Grumpier Slashdot Raw, Cooked or Well-done, it's all half baked. EPIC, The Architecture of the future, always has been, always will be. |
#49
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Gregory W Blank writes:
"To announce that there must be no criticism of the President, or that we are to stand by the President, right or wrong, is not only unpatriotic and servile, but is morally treasonable to the American public."--Theodore Roosevelt, May 7, 1918 You need to check if it is 35%, or if it is diluted down for filling as is. 35% is diluted before it is used in the batteries, but nowdays they may well be shipping the more dilute read to use conc so as to not confuse the burger flippers. -- Paul Repacholi 1 Crescent Rd., +61 (08) 9257-1001 Kalamunda. West Australia 6076 comp.os.vms,- The Older, Grumpier Slashdot Raw, Cooked or Well-done, it's all half baked. EPIC, The Architecture of the future, always has been, always will be. |
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