I appreciate the thought behind the idea of weak pickle being a
safety device. The problem is my little brain seems to remember a
time when I used to teach chemistry. I seem to remember that in some
cases using a dilute acid actually made it more potent, this might
only be true of a few acids however. Some dilute acids ionize more
than more concentrated solutions. I am not talking about acids so
concentrated they are fuming, but so concentrated that the water does
not ionize the acid as well as it would with a more dilute solution.
A bit weird - weaker = stronger. I have found this to be true with
nitric acid and aluminum where a weaker solution will work where a
stronger one does not (there are oxidizing actions at work here to
confound things). The same oddity seems to happen with some of the
sulfuric acid salts.
Be that as it may, I have also begun to “stifle” myself and not
quench my hot silver in the pickle. I have never proven the following
two reasons beyond a doubt, but there is some evidence to support my
guesses. First, quenching in hot pickle seems to entrap some of the
acid in the “open” pores. Might be black magic, but I seem to have
better luck on subsequent operations if I quench in water first. I do
love the way the oxides vanish with the hot acid quench however. The
other issue which concerns me personally a bit less is the idea that
you volatilize or boil off some of the acid salt when you hot quench
rusting tools and rotting lungs.
How do the rest of you deal with the hot quench issue?
The other issue which concerns me personally a bit less is the
idea that you volatilize or boil off some of the acid salt when you
hot quench - rusting tools and rotting lungs. How do the rest of you
deal with the hot quench issue?
I have some little hot plate for warming a cassarole? that I found
at a thrift store, I have a pyrex beaker with granular ph down and
water for the pickle. I have a ceramic saucer as a lid. I rarely put
anything in the pickle hot, but if I do, I only lift the lid enough
to be able to drop the piece in the pickle along the inside wall of
the beaker closest to me, and I immediately close the lid, no
splashing, minimal fumes produced, and I have excellent air flow that
disperses what little can escape. The only tools I have trouble with
rusting are setting burrs. All my pliers, mandrels, hammers, ect.
show no sign of rusting.
I never quench in hot pickle and in our school lab we also do not
allow quenching in pickle. I keep a water quench pot on my bench, and
we provide them on the soldering table in the school lab as well.
The reasoning behind this is exactly what you state… BOTH reasons.
But also, quenching in hot acid also can lead to splashes of hot acid
onto the skin, into the eyes, etc., which can be not-so-nice. In a
shared lab environment, especially, you may be splashing someone else
with the hot acid, so the limit of liability is not just personal.
I also sometimes do a repeated quench followed by more soldering
operations, and you really don’t want to be doing that with pickle.
Hope this helps!
Karen Goeller
No Limitations Designs
Hand-made, one-of-a-kind jewelry www.nolimitations.com
Quenching into hot pickle is a bad idea for several reasons. First is
the safety issue of splashing pickle that can be tossed about by the
heated item entering the pot. Second the larger amount of acid vapor
released into the air by the heated item entering the pickle. Metals
are crystalline structures that have discontinuities at the
boundaries between the crystal grains, these areas are more open
when the metal is heated and the pickle can indeed get into these
grain boundaries and cause problems later with soldering or even
potentially in certain alloys lead to stress corrosion cracking. So
water is a safer quench.
Jim
James Binnion @James_Binnion
James Binnion Metal Arts
I use sulphuric acid pickle hot and diluted because it is the
fastest acting. I have done the hot quench in the pickle too and as
you say the fumes and splutter are not worth it!
My acid container is a pyrex glass casserole dish with a stainless
steel lid, which sits on a hot plate with the thermostat tweaked to
keep it about 70-80*C. The fit of the lid must be such that the steam
condenses and runs back into the bowl so that the water lasts much
longer. Anyway, sometimes I lift the lid a crack and pop in a hot
item and drop the lid right behind it so that the splutter and fumes
are safely contained. A distant memory that sulphuric acid loves to
dissolve in water - so I wait about 10 seconds for the fumes to
dissolve into the steam and acid bath.
All up it is just as quick to quench in water and then swish the
item in the pickle for the same 10 seconds. After neutralizing the
item in a bi-carb of soda bath, any stubborn thick deposits of glassy
flux are shaken off by a short dip in the ultrasonic.
Depending on circumstances I do the normal thing and just leave the
item in the pickle for 5 or10 minutes.
I realize that many people have seemingly good reasons for not
wanting to quench in hot pickle, and they are welcome to them. I just
throw that sucker in there, though, and always have. 100’s of 1000’s
of times. I’ve never had any problems, any issues, and none of the
“might be’s” have ever come to pass. Since I’m an adult, I don’t
worry about acid spashing - I just don’t do it. You don’t want to,
don’t do it. But no, the sky won’t fall if you do. Silver to be
resoldered needs to be rinsed well, but that needs to be whether it’s
quenched hot or cold. It’s really a non-issue… Also, there’s the
thing about quenching metals too hot or too cool. But again, those
things apply whether it’s water or pickle. You are talking acid in a
concentration of something like twice that of vinegar.
The main issue, beside acid splashing, is that as I understand it,
sulfuric acid as a liquid is corrosive but when you make a mist of
it (such as by quenching in pickle), it becomes a carcinogen. Since
everyone is an individual some might not react to it as such, but
some would. In factory situations with steady mist exposure the
enamel on the teeth suffers. Hence the advice not to quench in
pickle. I find a quench in water, then into the pickle works fast…
Here is the other argument on quenching. If you are annealing, the
process of quenching is a thermal process, allowing certain metals
to retain their flexibility. However, when you are soldering, if you
quench even in a hot liquid, the thermal shock to the delicate and
fragile solder seam can create minute cracks. Others may chime in,
but quenching in pickle, not only thermally shocks your solder seam,
but the addition of a hot acid can create small pits in the solder
seam, especially with solders that have more alloy such as easy
solder. This was explained to me by Boris Bally when he studied in
Switzerland and honestly, it makes sense.
What is the rush? If you solder a joint, let it rest and allow the
solder seam to cool down a bit, then the heat in the acid bath will
do its work on reducing the oxides and flux. I just can’t see how
waiting 15 seconds would make a difference in cleaning, but the
benefits in waiting, a quick dip in water and then pickle would keep
acid out of your eyes and splashes around your sink at a minimal
amount.
A hot tool can look just like a cold one, and puddles of pickle can
look just like water.
What is the rush? If you solder a joint, let it rest and allow the
solder seam to cool down a bit,
There is no rush. There is no argument on quenching. Read my post
again. All I said, aside from the fact that obviously there is such a
thing as quenching metal TOO hot, whether it is water, pickle or
chocolate milk, is that I (and many collegues, too) have quenched
metal in pickle thousands of times with no ill effects. Many, many,
thousands. The important thing to understand in all things is the
difference between theory and practice. Yes, theoretically the pickle
can get inside the crystalline structure and all sorts of things. In
practice it doesn’t or if it does it makes no real difference. I’m
not arguing with anyone - you can put your metal in the refrigerator
if you want to. I’m just saying that it is common practice in a
production shop to quench hot or cold as the situation suits - at
times you’ll solder 20 items and the first ones are cool and the last
are hot - and none of the “could be’s” have ever happened. As long as
metal has cooled to a quench temperature to begin with, it makes no
difference to the metal itself if it is water or acid. Again, this
isn’t theoretical, this is been there, done that. I’m not saying
you"should" do it - do what you are comfortable with - but, no, none
of the dire consequences have ever occured to me or anyone I know.
Sparex pickle is really quite safe if used even remotely properly. My
suspicion is that a lot of the stuff about pickle is like the
disclaimers on the instructions for power tools - “DON’T do all the
stuff we might be sued for.” It’s just not rocket science. Been
there, done that.
However anybody handles their pickle, they are just going to have to
get comfortable with it. This whole topic is a “newbie” question,
because pickle is about as integral to jewelry making as milk is in
the kitchen - it is a fundamental, every day, every hour tool. Move
on, don’t agonize over it, it’s just not that complicated.