U of S | Mailing List Archive | alt-photo-process-l | acids

acids



On Mon, 8 Jan 2007, Jack Fulton wrote:

The 18% hydrochloric acid mentioned below is often title Muriatic Acid
and is 32% hydrochloric acid. This product can be purchased in most
swimming pool or spa supply stores.

At concrete and rock stores a product known as Concrete Etch, for the
cleaning of stone fireplaces and rock surfaces is sold. This is Phosphoric
Acid.

At any motorcycle shop you can purchase sulphuric acid because they
generally fill the small batteries used in motorcycles. I have actually picked
up a small container that is about one pint, for no cost.
Long ago I bought a gallon of "muriatic acid" at a paint supply store for $6, and was told it was 33%. (They also sell muriatic in hardware stores, or did.)

My lab grade 37% HCL was about $25 per pint. The two performed almost identically, BUT -- a warning to those buying a gallon of muriatic: In due course the plastic cap corroded (unnoticed by me) & all metal -- including my stainless steel sink and the light chain -- in the vicinity seriously corroded. And then the plastic jug started to go. Transferring to glass was a tricky operation, as is getting rid of the stuff down your drain. If you don't need heaps (as for clearing baths) -- lab grade in glass is easier. I still have some in the old wet darkroom... as well as phosphoric, glacial acetic, sulfuric, and god knows what else. (Maybe some day they'll find a way to fix your computer with an acid bath.)

Judy

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