Subject: Re: Descaling steel - phosphoric acid

From: Michael DeManche <[email-masked]>
Date: Thu, 13 Jun 1996 10:03:40 -0400 (EDT)

You can get small quantities of phosphoric acid at most marine supply
stores. West Marine caries a brand called "Rust Lock Metal Prep" in 1 qt size.

At 07:10 AM 6/13/96 -0400, you wrote:
>Just a comment about phosphoric acid. Bob Patrick recommended using phosphoric
>acid as a way of removing excess borax after forge welding. I use Oakite 31 in
>a 5% by volume (roughly) solution. It does a nice job. I'm sure other chemical
>companies would have similar products.
>
>I've also heard of using buffered phosphoric acid, but when I checked on its
>availability, I found it came in 55 gal. drum minimum. I didn't need that much
>help.
>
>Even though phosphoric is not as corrosive as HCl (muratic), remember to pour
>acid into water, wear goggles, and don't stick your arm in the bucket to get
>the parts out.
>
>Mark
>
>-- 
>Dr. Mark E. Williams
>Bldg N-159, Rm E-215
>NASA/GSFC/WFF/EG&G
>Wallops Island, VA 23337
>804-824-1744
>[email-masked]
>
>I wouldn't want to belong to any club that would have me as a member.
>Grouch Marx
>
>
Michael DeManche,  Ph.D.          Managing Partner
New Directions Research
_____________________________________________________________\
              concepts, market research, prototype development

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From: "Bruce M. Freeman" <[email-masked]>
Date: Thu, 13 Jun 1996 21:03:29 -0400

>Mark

Mark-
Buffered usually means a mix of salt and acid such that the solution acidity
won't change much with use.  With  H3PO4 (phosphoric acid)  you have a wide
range of choices.  Any idea what pH is desirable?  Any idea of the chemical
identity of this "buffered phosphoric acid?"  I'm guessing an equimolar mix
of H3PO4 and NaH2PO4 (phosphoric acid and monosodium phosphate).  I could
check the pH of a solution of that, if  you're interested.
Bruce