Try Precious Metals West. Those guys have always shared
willingly, and are knowledgeable.Their # is 1-800-999-7528. They
may not have the answer, but they know everybody. You also could
try Helmut Frye at Techform (platinum and hi-temp metal casting)
he’s a metallurgist, and could have an answer.
I hope you find a way of alloying for purple. I’ve had a piece
on the drawing board for several years. Cash was the delay, now
it may be suitability of materials. From what I’ve been reading
it doesn’t sound suitable for pave’. Post what you find out or
e-mail me @firstname.lastname@example.org.
P.S. If we all had shared say 10 years ago the parameters of
working with colored golds; imagine how much farther ahead we
ALL would be? Something to think about for you hold outs out
there. Take it easy.