Subject: How to buy sulfuric acid?

From: [email-masked] (Chester A. Roberts, Jr.)
Date: 1 May 1996 14:05:28 GMT

I'm at a stage in my locomotive construction where I'll be doing
silver soldering.  Kozo, in his articles on silver soldering,
recommends using a 10% sulfuric acid pickling bath to clean up
the metal work after soldering.  But HOW do you buy this stuff?
I've tried welding suppliers and drug stores.  Chemical suppliers
listed in the business-to-business yellow pages only sell in bulk
quantities.  So, to repeat the question, how DO you buy sulfuric
acid?

Regards, Chet

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From: [email-masked] (Bart Smaalders)
Date: 1 May 1996 17:18:23 GMT

I've found muriatic acid (hydrochloric acid) to work very well for
cleaning copper, brass, stainless and normal steel prior to silver
soldering.  I use ~10% of full strength as supplied for pool ph
adjustment - you can buy this at most hardware stores.  I tend to use
it a little stronger if I'm working with steel, as it speeds up the
reaction somewhat as does warming the work piece slightly.

My current boiler project for the Otter (our 19' steam launch, see URL
below) has me silver soldering 55 copper coils into steel nipples
welded into a 8" diameter drum.  Using hydrochloric acid for cleaning
works like a charm.  I mechanically clean the steel nipple insides with
a small rotary wire brush and then apply acid with a small acid brush
until the surface is a uniform gray color.  I then flush the nipple
with water and immediately apply a silver brazing flux that contains
florides.  The copper tube is cleaned with fine steel wool and then
receives the same acid treatment.  The copper immediately gets that
really "bright" look, and is then rinsed in fresh water and gets it's
own thin layer of flux.  I then fit the coil into the nipples and use
45% or 55% (the latter seems to work a bit better) cadmium-free silver
solder to joint the parts.  Then it's on to the next coil.  (next time
I'm using a simpler design w/o so many pieces :-)).

One nice thing is that the hydrochloric acid seems to be much
easier on cotton clothes than sulfuric - when I used to use
sulfuric acid in Chem 101 (some 20 years ago - eek!) I often 
ended up with a hole or two in my jeans...

If you're set on using sulfuric acid, car batteries use this for
electrolyte.  Any large battery supplier should carry it.

---
Bart Smaalders			Solaris Clustering	SunSoft
[email-masked]		(415) 786-5335		MS UMPK17-301
http://playground.sun.com/~barts			2550 Garcia Ave
							Mt View, CA 94043-1100

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From: Paula Trejo <[email-masked]>
Date: 2 May 1996 00:03:04 GMT

> quantities.  So, to repeat the question, how DO you buy sulfuric

Hi Chet,
You may want to check into using a product called Sparex No.1 for 
ferrous metals or Sparex No.2 for non-ferrous metals.  Sparex No.2 
is a pickle used by jewelers to clean metal after soldering.  It is 
fairly safe and can be used cold or heated (not boiled!).  It can
be purchased from jewelry suppliers.

Goood Luck,
--Paula

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From: James Foster x2912 <[email-masked]>
Date: Wed, 01 May 1996 16:52:23 -0500

> I've tried welding suppliers and drug stores.  

Try auto parts places. Sold for filling and topping off batteries.

                      
x

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From: [email-masked] (J. Kimberlin)
Date: 1 May 1996 15:49:13 -0700

In article <[email-masked]>,
>quantities.  So, to repeat the question, how DO you buy sulfuric

Use automotive battery acid.  Look in a chemistry handbook to find out 
what strength it is to start with, then dilute by pouring it into the 
proper amount of water.  If you add some hydrogen peroxide, you can avoid 
the black smut that forms on the copper when you pickle it.

JerryK

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From: [email-masked] (Peter Brooks)
Date: Thu, 2 May 1996 17:44:49 GMT

Well, you could try a few different sources:

There are scientific supply companies--  I believe that one of the largest is
Scientific Products.  I'd think you'd want to get that on a will-call, unless
the UPS hazardous material policy will actually let you ship it.

Automotive supply houses should sell sulfuric, since that's battery acid.

*Some* instant plumbing solutions are concentrated sulfuric acid, *and will
tell you*.  Beware of the others--you don't want to try sodium hydroxide.
I get mine (for drains...) from OSH, the oft-maligned super-hardware store
in San Jose.  They haven't gone to the 'twice as safe and 1/10 as effective
for only twice the price' junk completely here.  Yet.

Pete Brooks

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From: [email-masked] (Richard C Lucas)
Date: Thu, 2 May 1996 18:04:29 GMT

Check out pool supply stores.  Pool acid is either sulphuric or hydrochloric.
I've seen both types.  The hydrochloric sometimes is labelled as "Muriatic"

Dick Lucas

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From: Bruce Freeman <[email-masked]>
Date: 2 May 1996 22:06:23 GMT

> ended up with a hole or two in my jeans...

Just thought folks might want to know that the reason for the above
observation is that hydrochloric is volatile, where is sulfuric is
almost non-volatile.  (That makes hydrochloric more dangerous in terms
of fumes, but sulfuric is the stronger acid.)  Even dilute sulfuric 
dribbled on clothes will eat holes, as the water evaporates and leaves
concentrated sulfuric.

Bruce

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From: [email-masked] (David William Jenkins)
Date: Wed, 01 May 1996 21:53:21 GMT

>the metal work after soldering.  But HOW do you buy this stuff?
...

I was unhappy about having sulphuric acid in the house when my kids
were younger, so I chose to use citric acid.  This is commonly
available in chemists (drug stores) and commercial suppliers,
usually in powder/crystal form. Worth shopping around for a good
price, although you won't need so much.  I bought 3Kg in 1Kg tubs,
and I still have 1.5 tubs after four or five years of pickling
assorted stuff (including a largish boiler).

Even a saturated solution isn't especially dangerous, although I
wouldn't hesitate to rinse my skin if splashed, and wear rubber
gloves and eye protection when appropriate. 

It isn't quite as effective as sulphuric, but it does work - just
takes a little longer.  It's also easier to get rid of when you've
finished with it. It certainly doesn't have that nasty sharp
smell that sulphuric has!

It's certainly worth a try, if you can't get better.

David Jenkins              -- aka --             Lathyrus Computers Ltd
***********************************************************************
* All incorrect spelling and grammar is intentional.  Corrections are *
* superfluous and will be ignored.  So there.                         *

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From: [email-masked] (Your Name)
Date: 2 May 1996 20:38:51 GMT

Three possibilities-
1- buy it at an automotive parts store (used in car batteries)
2- buy at a jewelry supply or welding supply
3- don't use sulfuric acid, but a safer 'cousin', sodium bisulfate, sold 
as a silver solder pickle under the name 'Sparex', at jewelry supply 
store, or cheaper at a pool and spa chemical supply store to adjust the 
pH of water.

In article <[email-masked]>, 
[email-masked] says...

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From: [email-masked] (David P. Anderson)
Date: Thu, 02 May 1996 15:02:42 GMT

>Regards, Chet

Photographic supply houses, mainly wholesalers, usually sell it by the
gallon (33% concentration), and there are some mail order
photochemical suppliers that will ship to individuals, but it has to
go UPS or truck as acids aren't legal to mail.  BTW don't use battery
acid,  it's full of impurities and you never know what color your
metal will end up.

Dave

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From: [email-masked] (Joshua_Putnam)
Date: 1 May 1996 21:32:54 GMT

>quantities.  So, to repeat the question, how DO you buy sulfuric

Last time I needed any for cleaning purposes I just used battery
acid from the local auto parts store.

When I needed purer stuff for some electroplating I got it from a
local chem lab supply company -- chemistry labs often buy things
a quart at a time rather than in industrial quantities.

If you need something better than battery acid and can't find it
>from  a chem lab supplier, maybe some business that uses it would
sell you some of theirs, e.g. a plating shop or commercial
soldering/brazing outfit?

--

[email-masked]  is  Joshua Putnam / P.O. Box 13220 / Burton, WA 98013
                       "My other bike is a car."

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From: [email-masked] (Alan Heugh)
Date: 3 May 1996 06:25:32 GMT

In article <[email-masked]>, [email-masked] (J. Kimberlin) wrote:

> >the metal work after soldering.

  Avoid holes in your clothes - you don't need to handle concentrated
liquid sulphuric acid at all, in fact the commercial standard jewelry
chemical is "Sparex", available at any jewelry supply company. It's a dry
chemical salt that, when dissolved in warm water, produces mild sulphuric
acid. perfect for cleaning off flux and soldering residues. And, better
yet, the specific chemical is SODIUM BISULPHATE and it's available at
hardware stores and swimming pool supply companys (it's used to lower the
Ph - raise acidity). A small can of this "dry acid" may last years. Add a
few tablespoons to a quart of water, and heat it in a pyrex pot or even an
old crock pot. I keep a canning jar full and heat it in another pot of
water.

-- 
Alan Heugh   (360) 595 2563   [email-masked]
478 Rainbow Drive
Sedro Woolley, Wa. 98284

Rare skill. lost wax carving & jewelry designing - contemporary, antique, extremely naturalistic miniature sculptures: animals, flowers, attractive human faces & figures: email for example photos.