I’m in a pickle…perhaps someone out there can help.
I am using an 18k gold alloy that has a high percentage of copper.
When cast, this has a very pink tint. I like this alloy because it
will oxidize when I solder it. When I put it in the pickle, the
oxide is removed and a layer of fine gold remains on the surface.
Depletion guilding. I am using sodium bisulfate for the pickle,
occasionally using a hot mixture of 10% sulfuric acid with a "pinch"
of sodium dichromate.
If I wanted the metal to be pink, I simply removed the fine gold
layer by using abrasives. I am working on a new design series that
has a verydetailed texture done in the wax. I want to retain the
original pink color of the metal, but cannot use abrasives to remove
the surface. Dropping this alloy into the pickle results in a fine
gold surface. Electrostripping did not work. It will turn an
otherwise pink surface into a fine gold surface, and a fine gold
surface will simply get richer. I have been laser welding the alloy
into place. I need to move beyond this.
Can anyone suggest an electro/chemical means of stripping the fine
gold from the surface? Perhaps a coating that can be applied to the
surface prior to soldering that won’t allow it to oxidize and not be
removed by the pickle?