Q: I’ve got a Sparkie II “fusion” (capacitive discharge) welder, and I’ve been having trouble attaching nickel silver findings to my copper parts. Do you think it’s these metals in particular that are the problem, or is something wrong with the machine?
I’ve noticed that after some use, the fixtures that hold your parts on one of those welders get a layer of oxide and grunge on their lower surface that reduces the contact between the fixture and the piece. When that happens, the resistance between it and the piece is equal to or greater than to the contacting welding nib, so you then get a welding arc between the piece and the fixture, rather than entirely between it and the finding.
The solution is to remove the fixture, and file or sand the surface back to bright, clean and smooth. That should help. Sometimes, a little bit of saliva on the piece will help too; the moisture seems to improve the contact between the fixture and the work. Then when the weld takes place, the moisture in the weld area reduces the cleanup of smoke stain that’s required. It varies a lot from metal to metal, but give it a try.
Generally, the main things I’ve had trouble with, with the Sparkies, is in welding sterling findings to sterling silver parts. Sterling-to- sterling welds have a tendency to come out somewhat brittle, and it sometimes takes a couple of tries to get a secure weld.
by Peter W. Rowe M.F.A., G.G.