On Sun, 06 May 2007 09:04:12 -0700, in rec.crafts.jewelry lemel_man
Post by lemel_man... snip
Use flux in any case, which will protect
against oxidation, and if using palladium based solders like the lower grades of
traditional platinum solders, should protect the solders too from hydrogen
absorbtion. (I use 1000 platinum solder for palladium, and it seems to work
fine).
Interesting.
This is my first attempt at using Pd and all the tutorials on Ganoksin
state "don't use flux", so thanks for your warning.
So far I've successfully tack-welded bits together with my PUK-2 (works
fine) but have been nervous of actually soldering the stuff. I feel a
little more confident now.
Well, I might be wrong on that too. I'm mostly a platinum and gold worker. My
experience with soldering palladium is mostly with soldering it to gold or
silver, as in using palladium settings with gold jewelry. In those cases, flux
is critical, because if the palladium oxidizes, the solder can still seem to
flow, but the joint will not be good. Soldering palladium to itself, using the
lower temperature grades of traditional platinum solder (which are made of
palladium and silver, or pd and gold, usually, not platinum itself), puts the
process in a higher temperature range, and is then using a solder more closely
matched to the palladium When soldering platinum itself, flux is not a great
idea, because many of them contain one or another silicate containing chemical,
and at high temperatures, in a reducing atmosphere, sometimes silicates get
reduced to silicon metal, which then can contaminate the platinum. This is the
big problem with carbon and platinum too, as I understand it, because at high
temps, carbon is an exceptionally good reducing agent, and can cause even things
like the fused quartz in a platinum soldering block to start to reduce like
that, thus contaminating the platinum.
Now, I don't know if the lower temp range we're talking about here gives the
fluxes and equal risk as with higher temp soldering or welding of platinum.
Frankly, though I doubt it. And i DO know that if the palladium oxidizes, then
a good joint will be harder to get, and the combination of a slightly reducing
flame and flux helps to avoid that. But don't get too reducing a flame, because
then you run the risk of hydrogen absorbtion by the solder, giving you pits and
all...
That's how I see it, at any rate. But as i said, I've only soldered palladium
to itself a few times. Most of the work I've done with it involves soldering it
to gold or silver. So I might be wrong for the hgiher temp work. If the
Ganoksin articles contradict me, I'd suggest going with them instead. Just be
sure they are specifically mentioning palladium, rather than being instructions
for working in platinum.
Peter