We had a very interesting occurrence at the Art League Jewelry
Department this last Wednesday.
A new student of mine had built a copper model of a ring that she
wanted to produce in silver, & I suggested to her to tumble barrel
the piece for a quick finish.
She brought it back to me later, & the whole piece was now silver -
honest - of course she asked me what had happened - I was thinking -
how can we market this! Then I thought my other students were
pulling my leg.
So we put a piece of sheet copper in the tumbler, & yet again it
came out silver in color.
What is going on here?
Here’s the facts - the piece was copper; the tumbler was a standard
Lortron barrel tumbler, with stainless steel shot - Rio’s super
sunsheen burnishing compound + water. Nothing else was in the barrel
that we could see.
The only odd thing was that my new student had chosen the barrel
shot we usually reserve for PMC - no pin shot, only rounded shot.
Is it possible that particles of PMC can be retained by the
stainless steel shot, & then re-deposit it onto a base metal?
So of course, all my other students threw their copper pieces into
to barrel - some pickled; some not - all the pieces came out
silvered, but the one’s that weren’t pickled had a lesser, more
mottled deposit of the silver color.
My other concern is that I know mercury can coat metal - to what
extent I don not know, & I don’t know how that could have
contaminated the shot, but would this account for it?
I look forward to your comments