Gradient temperature casting is a concept that was introduced by Dr. John Nielsen in the American Jewelry Manufacturing Magazine. In a series of trials to eliminate porosity which pervaded castings at the sprue junction, an experiment of a 10-minute delay from oven to casting machine was created. The first thousand castings were checked for shrinkage porosity by the sprue without a single defect. Gradient temperature casting is another tool that works frequently for the castor, but not always. Variables include dependency on alloy selection, temperature of the flask, temperature of the metal and casting equipment used.

Author: Larry Diamond