The permeability of gypsum-bonded silica jewelry investment was measured at the elevated temperatures that are typically used in jewelry investment casting operations. Measurements were performed on samples with cylindrical geometries that were similar to the gemetry of investment casting molds. A unique method for measuring mold cavity pressures, temperatures, and flow rate of air through mold walls was developed and utilized.

Author: John C. McCloskey, David Allen, Alfred Thibodeaux