Friday, June 06, 2008

What about those alloys

It is being reported that some palladium rings are too brittle to size much. These reports coincide with Pd/Ru/Ge alloys that have been extruded. Beware platinum family alloys with palladium! They can be brittle. They are excellent for continuous cast like seamless bands, and they stamp really well.

But as we all know lost wax casting is different. Just like gold, the best fabrication alloys are not often the best casting alloys. To a lesser extent this is true of platinum. The traditional blend of 9o0%Pt and 10%Ir was the casting mix, and 95%Pt 5%Ru was the fabrication/stamping blend. It's no coincidence that Ru is the tricky one to cast overall.

The disclaimer here is that at least one caster, (TechForm){ swears by the Pd with Ru blend. Different casters use differing plasters and methods, so these are general rules that certainly have exceptions.

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