On Aug 8, 9:21 am, wrote:


I am taking stamped metal parts (nickel silver) and heating them up to
about 450 - 500 degrees. Many of them change color from a shiney
silver to a bluish color. This is the effect I want.

Generally, patina of metals is controllable. Find your way to a good
library
and look for Metal Finishing Handbook, there are recipes for these
situations. If your alloy doesn't change, minor cleaning/preparation
of
the surface is all it takes to get a uniform result.

Look up shakudo when you have a few spare moments.