Andy, This is the pickle I use for depletion guilding. It an old,
traditional formula using sulfuric acid, so this is NOT recommended
for home use!
H20…1 quart
Sulfuric acid (C.P.)…3-4 oz.
Sodium dichromate…1 1/2 oz.
*use hot, but not boiling (you do not want to see steam rising)
The sodium dichromate acts as an inhibitor to prevent the etching of
the base metal (allows the pickle to attack the oxides only). I
polish my jewelry first, to remove any scratches. Then, I heat the
piece with an oxidizing flame, which completely blackens the piece
in firescale. I let it air cool, then I place it in the pickle for
several minutes.
I am using an 18k alloy of 15% copper, 10% silver. The result is a
very heavy coating of 24k. The higher the copper content, the more
dramatic the results.
To those reading this, who are not familiar with, or comfortable
working with, acids or do not have adequate protection, ventilation
or disposal facilities, do not try to use this. Sulfuric acid can
cause burns to the skin, eyes, and lungs if not handled properly. I
am providing this to those on the list who are able to work safely
with this pickle, and who will find this formula valuable. I use
sodium bisulfate (from my pool supply company) in my pickle pot for
daily use, since I find it much safer to be around on a daily basis.
I keep the depletion guilding pickle safely stored for the time that
I want to use it. After I use it, I let it cool and put it back into
storage. It seems to have a long shelf life.
Doug Zaruba