"Ken Grunke" wrote in message
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snip----

This is not a strong argument for using the stuff, Harold--but of course
you wouldn't leave a piece of steel in the acid longer than needed to
dissolve the rust.

Ok, I'll provide an argument for not using it. Hydrogen embrittlement.
If your piece is hardened, that's one of the hazards. Easily eliminated by
a prolonged roast at something like 375° F, though.

I tried it today, just to make sure I wasn't a brick or two short of a
load. A smidgen of straight-from-the-jug muriatic in a plastic cup
dissolved a heavy coat of rust on a scrap piece of steel in 2-3 minutes,
leaving a dull gray, but very clean surface.
That
rusts immediately. It removes rust all too well, Ken. That's not my
argument. I used to buy the stuff by the drum when I refined precious
metals. Everything in my lab was rusted that was made of iron, including
stainless items. I ran a fume hood almost constantly, but it's next to
impossible to escape the fumes. That's yet another argument against using
hydrochloric (muriatic) acid.

It's quite forgiving as far as handling goes, so long as you keep it out of
your lungs and eyes, but the fumes raise all kinds of hell with things.
If one must use it, it's best done outside unless there's a decent fume hood
available. I've had to do some serious rust removal on large items, doors,
doorframes, etc. I've used phosphoric with super success, and the surface
left behind is well prepared to receive paint and is rust resistant. Much
better choice, but definitely shower.

I'm definitely interested in alternatives, having some rust problems of
my own in my shop. I just happened to have a partial gallon of muriatic
around, and it's come in handy for small rust removal jobs.

Chuckle! That may very well be the source of your rust, even if you keep it
well capped. If you have a safe place to store it outside, get it there
as quickly as possible. I've had items destroyed that were stored with
well capped gallon jugs of hydrochloric. It's next to impossible to
contain the fumes. Currently I have several gallons of acids (nitric,
hydrochloric and sulfuric) and keep them all outside. Luckily, I have enough
acreage that it's possible to store it safely. There's no way in hell it's
ever going to get stored inside the way I did when I was refining. I got
tired of everything getting rusted.

Good luck!

Harold