We just received some vintage pieces of jewelry that are marked 925 and are clearly electroformed. As far as my research has shown, electroplating/electroforming alloys isn’t all that common and I have not seen anyone selling solutions for sterling. Am I missing something? Has anyone seen pieces like this?
Electroforming is subtractive, versus electroplating which is additive. I have a jeweler / silversmith friend who set up a program /lab while getting her MFA in jewelry at UW back in the 70’s. I’ll get in contact with her and try to you get some images (or where you might find some). Her work is extraordinary, mid-century inspired pieces, and was published in several books. She’s been a direct inspiration in growth as a jewelry designer / maker.
I think Eileen may be confusing electroforming with electro-etching. Electroforming is an additive process, much like plating but thicker. It usually involves painting a conductive lacquer into a mold or onto a mandrel of some kind, or a natural object like a leaf, which becomes the cathode in an electrical circuit where the anode is a piece of pure metal, usually copper, also suspended in a solution containing a lot of metal ions, Metal is then slowly deposited from a solution, which solidifies the form. If it’s a mold, at some point the solidified piece is removed from it, and both sides are plated for a while. Electroformed parts can be used as is, or plated with other metals.
It’s possible, with the right equipment, to electroform alloys like sterling, but it’s not easy. You need a computer control that can switch between anodes of the constituent metals so it builds up the alloy rather than a pure metal. The solutions would probably be a mixture of silver and copper solutions so ions of both metals would be present. How old do you think these pieces are? I don’t think people have been doing alloy electroforming for very long, although I could be wrong about that.
Thanks Andrew–that’s what I was looking for. I was surprised that there were no cyanide-like solutions for sterling like there are for karat gold. The pieces I have look to be mass produced in Israel, but I don’t know the maker so I had no way of confirming whether this was even a possibility. Any metallurgist want to explain why karat gold, brass, and bronze can be electroplated/formed with cyanide and sterling can’t?