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Post by durhambuilder on Apr 23, 2008 12:39:51 GMT
I think this may have been covered before if so sorry. My local hardware shop sells a drain cleaning product (Barrettline Amo Kleen Knock out) which is essentially a litre of 97% sulphuric acid for £3.99. Any ideas on who this should be diluted to make a suitable pickle or is it just trial and error?
Thanks
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Post by jgb7573 on Apr 23, 2008 13:50:24 GMT
If it was straight acid I'd say add 1 part of acid to 10 parts of water, slowly, stirring the water as you go. The water will warm up as you mix in the acid. If it looks like it's getting hot, stop adding the acid and let it cool down.
John
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Post by AndrewP on Apr 23, 2008 15:25:15 GMT
If that is Barrettine (note spelling) Amo Klean spirits of salt then it is almost certainly hydrochloric acid - not really what you want. Spirits of salt is the historical name for Hydrochloric acid, along with muriatic acid which you will still see sometimes.
John's dilution instructions are spot on and necessary - add acid to water slowly and stirring.
Cheers, Andy
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Post by durhambuilder on Apr 23, 2008 17:10:11 GMT
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Post by AndrewP on Apr 23, 2008 21:54:45 GMT
Great ! go for it, please let us know how you get on because that is a much better price than my jewellers supply houses want for sulphuric, and they won't post it!
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Post by ron on Apr 24, 2008 8:48:40 GMT
Auto Shops are another source of sulphuric acid or at least my local one is, but it's not as cheap as the drain cleaner.
Ron
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Post by robert on Apr 24, 2008 8:54:06 GMT
I have tried to get Sulphuric acid and failed although I can collect it from many miles away. I was advised to use Sodium bisulphate, used to acidify swimming pools, and have done so with some success although the bucket life is short. How does it compare to sulphuric acid? Sodium bisulphate can be slow and I don't understand the chemical process either.
Robert
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Post by modeng2000 on Apr 24, 2008 9:23:22 GMT
The sulphuric drain cleaner I use comes from my local plumbing trade outlet (they sell to anyone  and is around a £1 per liter I think. I have had no problems using it in the way suggested at around 10:1. The water does get hot if you add the acid too quickly. John |
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Post by alanstepney on Apr 24, 2008 12:08:07 GMT
Sulphuric acid is the "traditional" pickle, and can still be obtained. One oft-suggested alternative is acetic acid, which is, or was, easier to find, and, allegedly, not as harmful when disposed of. However, I suggest reading what Johnson Mathey suggest using. They, after all, are the main makers of silver solder and flux, and should know what they are talking about. www.jm-metaljoining.com/ gives a lot of information, including that the correct methid of cleaning after using each type of flux. Acid, is NOT needed for easyflo, one of the most common fluxes. Warm water will work, although any weak acid will speed up the process. A 10% solution of Sulphuric, is, however, suggested for Tenacity flux. |
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Post by AndrewP on Apr 24, 2008 20:48:37 GMT
Sodium bisulphate is the stuff sold as 'Safety Pickle' which I use every day on silver and gold. It isn't as quick as Sulphuric and does benefit from warming - mine sits on a slow cooker plate all the time, but that is a little difficult to arrange if your pickle bath is a dustbin so the boiler will fit in it I admit.
I haven't noticed a short bucket life, I probably only renew mine every 3 months or so, unless I manage to contaminate it by getting something ferrous in there. Maybe the heat helps more than I thought.
Swimming pool acidifier (ph down) is the pickle of choice for a lot of smiths in the states.
Cheers, Andy
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tcase
Involved Member
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Post by tcase on May 15, 2008 11:26:10 GMT
Snip... Acid, is NOT needed for easyflo, one of the most common fluxes. Warm water will work, although any weak acid will speed up the process. A 10% solution of Sulphuric, is, however, suggested for Tenacity flux. There are two factors involved, getting rid of flux which for Easyflo and equivelants is best done with hot soapy water. The other problem is oxidation products and discolouration and there your options include Sulphuric acid, Citric acid, a saturated solutuion of salt and vinegar (Helps to live over a chippie) and the ever popular elbow grease and scotchbrite etc, |
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Noddy
Statesman
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Post by Noddy on May 15, 2008 12:02:01 GMT
Saw the "add a few drops of bleech to preserve citric acid" heresy repeated in one of the magazines again a few days ago.
it's a complete waste of time effort and materials.
sodium hyperchlorite (bleach) is strongly alkaline, so it neutralises some of your acid, and in the process gives off chlorine gas.
Chlorine is at best annoying, at slightly higher doses it hurts your eyes nose and throat, and gets worse from there to ....
well, gassing you... painfully at that.
Chloride in the workshop are also a good way to encourage corrosion, possibly even encouraging stress corrosion!
A good strong (cup full of powder in a bucket of waterish) solution of citric acid doesn't go off.
Used organic acids might be ok for the general environment, but their cargo of heavy metal ions are not.
Keith
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Post by yorkshireman on May 15, 2008 15:17:20 GMT
I just bought a bottle of Drain Cleaner from B&Q (£7.98). This stuff is 92% Sulphuric Acid. Diluted with some proper care, this makes a perfect picke bath.
Johannes
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and is around a £1 per liter I think. I have had no problems using it in the way suggested at around 10:1. The water does get hot if you add the acid too quickly.