The investment stage: a slurry of zircon flour suspended in colloidal silicate is put on each mold with graded layers of molochite that add body to the mold. The layers have to dry thoroughly before the next is added. Any trapped moisture will cause the mold to become friable and weak. The waekness will become painfully obvious during the burnout and firing stage.

Investing the waxes is hard work too, it took about five hours to coat all of the peices which got very heavy by the time we coated them for the last time