Q: Is it worth it to try and remelt my sterling silver scrap and make new wire and sheet? Or is it more feasible to take it to a refiner, even if you don’t have a whole lot?
A: Some refiners, David H. Fell, (213-722-9992) for example, have no automatic minimums, and don’t charge an assay charge if your scrap is 88 percent silver or better, and you are only asking for payment on the silver, with no recovery or assay for other metals (such as gold) in the scrap. Their payment schedule depends on how much you send. More than 100 oz and they pay 93%. less than 20 oz and it’s 85%.
While you can melt down scrap sterling silver in an alumina or clay/graphite crucible, clean it with flux with flux when molten, and make usable wire by drawing down the rods produced by the steel molds available from jeweler’s suppliers; making decent silver sheet metal is a little tricker. It is hard to get a good enough pour so there are no blisters in the sheet, although you can simply avoid using those usually minor areas of the sheet, and save those portions for the next melt. Wire is much easier to make.
But one cannot assume that silver solders have the same silver content as sterling. Plumb gold solders are made with the same gold content as they are marked, but with silver solders this is not the case. Silver solders lower their melting point by adding more copper, and then adding zinc to the solder, in increasing amounts, depending on the grade of solder. A medium silver solder is only 70 percent silver, so silver solder in your scrap will lower the silver content of the whole melt, although this is compensated for to some extent by zinc burning off in the remelting process. It can also, if not completely mixed, cause inconsistencies in the resulting metal Again, this seems to be less of a problem with wire. I’d recommend not reusing solder-contaminated scrap for finer or important pieces, or for complicated constructions, or in work that is expected to take a very fine polish.
by Peter W. Rowe M.F.A., G.G.