Resin patterns used for rapid prototyping work or small production runs are difficult to burn out completely when used with jewelry investment. As a result, the castings produced from them often have poor surface finish and require extensive finishing. The effect of modified investments on the burnout was examined and found to make little difference. Variations in the burnout cycle to accelerate combustion of the resin were tested. Immersion of the flask in a furnace at 600°C (1112°F) followed by heating to 730°C (1346°F) was beneficial in improving the quality of castings of jewelry pieces.

Author: Dr. Ian McKeer