Re: Technical Grade Muriatic Acid

For the record -- a couple of points: My reagent grade Hydrochloric acid,
bought AT LEAST 15 years ago from Tri-Ess, was 37% (noted in the catalog &
once upon a time on the label) and as I observed previously did not
perform any better, in fact in some cases not as well, as muriatic.

However, it does FUME right through the bottle cap, even when duct taped
around the top. I kept all acids sequestered in shelves at the far end of
the darkroom, and ONLY the HCL label is deteriorated-- so badly that I can
only make out a very faint "Tri-Ess" in one corner. That's the original
bottle came in.

The muriatic, which I had in its original gallon jug in the studio, had
other problems -- ate right through the container and out onto the wooden
floor in a few years (tho the 200-year old wood essentially shrugged it
off). Tho a plastic bottle of the same muriatic in the darkroom is fine,
including the label, but that was covered with a wide band of cellulose
tape.

I moved the studio leaking muriatic to a glass jug but it ate through the
cap and corroded the underneath of the STAINLESS STEEL sink it was under,
also other metal within a few feet radius. In other words, long-term
storage is an issue, especially if you buy the hardware store gallon. (By
this time I wasn't using it any more, moved it to the yard, where the last
few inches gradually evaporated, not even a blip in the NYC air.)

But a couple of other notes on acid-- As I recall, sulfuric is the one
that spatters if you pour water into it, which I took to mean "fuming."
The label on the sulfuric, same vintage, on the next shelf, marked 48%
(tho I don't know if that's reagent grade) from Photographers Formulary is
as clean and bright as the day it arrived.

cheers,

Judy

On Sat, 8 Oct 2005, Etienne Garbaux wrote:

> Michael wrote:
>
>> So what is the correct proportion to use to make Aqua Regia? Does using a
>> less concentrated form simply give a less concentrated Aqua Regia mix (read:
>> weaker)?
Received on Mon Oct 10 00:04:53 2005