In terms of quenching in alcohol.... presuming one manages the
You don't generally ignite the alcohol. In many years during which I
occasionally use an alcohol quench, I can recall only once when the
The reason is that the metal enters the liquid quickly, and after
that, while the metal may be hot enough to ignite the alcohol at the
metal surface, there's no oxygen there, only the alcohol vapor layer.
No oxygen, no fire. And if by chance you do light the alcohol by
mistake, the only caution is don't drop the container by accident.
Generally you're doing this with the alcohol in a small container
(glass, not plastic). If the alcohol should catch fire, just drop
the lid on the top and it goes out.
- I have to ask - why? is there an advantage I'm not understanding
- c. f. water or oil.
You'd use an alcohol quench for much the same reason you'd choose a
water or oil quench. A different rate of cooling. With alcohol, when
the hot metal enters, it instantly forms an alcohol vapor layer
around it, and cooling is the rate at which heat is transferred via
that vapor layer. that layer persists longer than the similar layer
with an oil or water quench, so the overall rate of cooling with an
alcohol quench is slower, and thus causes less thermal shock to the
metal. Some of the metals we'd like to quench after annealing in
order to get maximum softness, ie red/rose golds and some white
golds, are "hot short" enough that if they quench too quickly from
too hot a temp, they can crack. Alcohol provides a gentler, slower
quench which won't cause cracking, yet is still fast enough to not
let the metal cool slowly. It's by a significant margin the best way
to quench rose and red golds in particular, which not only need the
quench for maximum softness, but which can become brittle and hard if
not quenched, but can crack if quenched too quickly. A number of
nickel white golds respond best to an alcohol quench too.
Let the metal cool enough so it's no longer glowing (meaning down
around 900F or less), but not much cooler than that. Then drop the
metal quickly into the alcohol so it's totally immersed. That avoids
any ignition of the alcohol. Then wait till you hear it actually
quench. That can take a surprising amount of time, though usually
more like five or ten seconds.
I don't use a seperate jar of alcohol for this. I already have a jar
of alcohol and boric acid powder on the bench, so when I need to use
an alcohol quench, I quench in that same jar. The boric acid has no
discernable effect other than meaning I need to rinse the piece off
There are two other methods of quenching (meaning simply to cool the
hot metal quickly) that can be useful. I find them real problem
solvers when I'm working with rose or red gold jewelry that already
have stones set. Obviously, while diamonds can take the heat of
soldering, they usually don't much like quenching.
with rose or red gold jewelry that already have stones set.
Obviously, while diamonds can take the heat of soldering, they
usually don't much like quenching.
Two ways to cool the rose/red gold quickly enough to avoid hardening
or cracking is with either a blast of compressed air or a blast from
a reasonable distance with the steam jet of your steam cleaner. Both
can cool the metal quickly without damaging your diamonds, cooling
the metal about as fast as your torch flame heated it up in the first
place, yet without quite the shock of a sudden quench.