I thought I’d add a few more details to the process of preparing
gold granules for granulation, as described by Sandra (Sandra and I
both attended Cecelia Bauer’s classes).
Before placing anything in the copper dish, place it over your kiln
(you need to use a beehive kiln for this) until it becomes oxidized.
Remove the dish from the kiln and let it cool completely. Then add
some pickle (we have always used Sparex, I do not know whether other
pickling compounds would also work), your granules, and some coiled
up iron binding wire (the iron is what will cause the copper oxides
suspended in the pickle to adhere to the granules). Place the dish
on a wire screen, and put the whole thing back on the kiln. Using a
pair of tweezers, rub the wire all over the granules, you will see
them turn from gold to pinkish brown. Remove the dish from the kiln
and allow to cool, them remove the granules and rinse them in water.
The granules are now ready to use for granulation.
I believe that Sandra’s article in Lapidary journal describes the
process of gluing the granules to a backsheet, as well as how to dry
the piece before firing. When you fire a gold piece with granules,
it is very different from a silver piece. With silver, you are
trying to get the backsheet to “flow” (i.e., to melt slightly on
the surface, which will fuse with the granules). With gold, you
heat the piece until you see the gold granules become bright gold
again (indicating that the copper coating has burned off of the
surface of the granule, leaving a very small bond at the point of
contact between the granule and the backsheet).
I hope this helps.