I have recently been told a couple of things that seem to be
inconsistent with my understanding of the soldering process:
I was told that immersing a sterling piece into the pickle after
soldering lowers the melting point of the solder in that piece and,
to avoid that, you should quench in water until you are finished
soldering. I understand that repeated heating of solder raises its
melting point because the heat removes some of the zinc, but I dont
understand how the pickle would lower the melting point.
I was also told that allowing sterling to air cool after
soldering will prevent it from becoming malleable as it does when you
quench it after annealing.
Thanks for your help-I learn so much on this forum.
Emie Stewart
I was also told that allowing sterling to air cool after soldering
will prevent it from becoming malleable as it does when you quench
it after annealing.
Ah, the perennial question.
Some people always quench sterling. Some people never quench
sterling.
You may quench it, but only after it cools down to 700 degrees. When
is that? I dont know, so I dont quench.
Quenching it too hard, yes, will keep it from being annealed.
(you will get lots of different views on this one. Try it and do
what works for you.)
Also, lots on the archives on this one. Search on anealing.
I was told that immersing a sterling piece into the pickle after
soldering lowers the melting point of the solder in that piece
and, to avoid that, you should quench in water until you are
finished soldering. I understand that repeated heating of solder
raises its melting point because the heat removes some of the zinc,
but I dont understand how the pickle would lower the melting point.
It will not affect the melting point but it is still not advisable
to quench in pickle. It will get pickle deep into areas of the work
where complete removal and neutralization is going to be difficult.
This residue can cause problems in future soldering. Also the hot
metal into pickle will put a lot more pickle vapor into the air and
may splash it over you as well.
I was also told that allowing sterling to air cool after soldering
will prevent it from becoming malleable as it does when you quench
it after annealing.
This is true but, it is not a significant difference. To get the
softest sterling after annealing you need to heat to above
1382F/750C then quench immediately.
But there are several caveats to this
almost all the silver solders are either molten or beginning to
melt (exceeded their solidus) at his temperature
it is fairly easy to fracture sterling when quenching from this
high a temperature if its crystal structure has been compromised by
improper working (over annealing is one way to do this)
So unless you have some overriding need for the absolutely softest
sterling, annealing from this high a temperature is not a good idea.
You can get very good results from annealing at 1100F/593C and be
much less likely to ruin your work.
I too am very interested in the answers from other Orchidans.
My instructor taught me that you quench in water than pickle & clean
off prior to any additional soldering to ensure that the surface is
ready to receive additional solder. (if its dirty, the solder not
flowing). If I only have to quench in water & then can proceed to
doing additional soldering, it would save a lot of time. Or maybe I
am not understanding the question.
I work for a large steel mill. We make extremely large (up to 40
long & 75" in dia.) pieces from different types of steel. Some pieces
are air cooled, & some get heat treated (to guarantee they meet metal
properties for hardness, tensile, etc.). Some are quenched in water,
some in oil. It all depends on the type of steel we are working with
& what the properties need to be to meet spec. We normally shot blast
(with steel shot) or machine the “scale” off the pieces as part of
the process. We dont solder anything though, we do weld repair on
occasion.
If I only have to quench in water & then can proceed to doing
additional soldering, it would save a lot of time. Or maybe I am
not understanding the question.
Quenching and pickling are two seperate operations. You CAN
physically quench in the pickle to speed things up, but this risks
spattering hot acid on you or the surrounding area. Not so safe. So
quench in water to quench. Then, if it needs pickling to remove
oxides or spent flux, or whatever, then pickle it. Not everything
needs to be pickled after heating. If properly protected during
heating, you don’t have oxides to pickle off. In those cases, you
could continue directly to other heating operations. The quench
itself will remove some of the protective flux or whatever you’ve
used on the metal, so you will still have to make sure it’s properly
fluxed or fire coated prior to reheating. If you let the silver air
cool rather than quenching, then you can often just reheat without
recoating, of the coating is in good shape still. And since you’re
going right ahead and heating the metal again, there’s no real
benefit other than speed, to quenching. Quenching results in less
chance for the metal to harden by precipitation or age hardening (two
names for the same thing). Since you’re not holding the metal at temp
for that, the effect is slight anyway, and since you’re going right
back to heating again, it’s negated anyway. Your call as to how you
wish to work. But quenching directly in the pickle can be dangerous.