Darcy, Heat treating success with precious metals depends on the
alloys that make up the specific metal. Copper is the metal that
allows gold and silver to become heat hardened, and also facilitates
age hardening and work hardening. Since most palladium white gold has
no copper or a tiny proportion of copper, it is not capable of be
heat hardened. It is also won’t work harden to a springy state and,
therefore, clasps, for example, should not be made out of palladium
white gold. Your best alternative for heat hardening white metal is
SK platinum from Hoover and Strong. However, it is more costly even
than other platinum alloys. This may make it’s use prohibitively
expensive, even though pieces can be made thinner and lighter.
18K white gold alloyed with nickel work hardens well, but I don’t
believe you can heat harden it. I may be wrong about this, I have
never explored heat hardening nickel white gold as it work hardens so
well.
Larry Seiger
JA Certified Master Bench Jeweler