Investing and burning out the wax

For this next part I shall use the wax of a sculpture I call China Doll..

The Flask

The wax is invested, which means it is suspensed in a block of a plaster/sand mix inside of a sheet-metal cylinder we call a flask. The ring of chicken-wire you see beside the flask will be placed inside before the plaster mix is poured in. It reinforces the plaster.

The flask is removed after the plaster mix has set, and the investment is moved to the burn-out kiln. This investment weighs between three and four hundred pounds; many weight more. I built that gantry crane to handle them.

Here is a different investment before the flask has been removed. It is sitting on the base of the burn-out kiln. After the flask is removed, the kiln will be lowered, a propane burner lit and inserted, and the temperature taken up to 1000F. An investment this size needs to be kept at that temperature for five days in order to burn out all of the wax residue. Wax residue creates gas when the molten bronze is poured in. Not good. Disasterous in fact.