Ultrasonic Burnishing of Platinum and Palladium Castings

On a recent project I was asked to provide a consult for a client working on a tedious project. A New York jeweler was trying to polish a very intricate palladium casting and finding subsurface porosity in tight areas. There was considerable detail in this sculptural piece which required a smooth and clean surface and he had tried all sorts of polishing papers and compounds.
Bench jewelers who work with platinum and palladium on a regular basis will tell you that PGMs (Platinum Group Metals)…