DAVID REID TECHNIQUE OF LOST WAX BRONZE CASTING
In part one, David Reid took us through the process of making a wax model fixed to a sprue and cup. He also made a wax button cup that will become the crucible for the molten bronze.
In this, part two, David demonstrates the making of the ceramic shell and crucible followed by burning out or ‘losing’ the wax.
Before beginning the ceramic shell process, it is useful to note the weight of the wax used. You will put metal weighing at least 10 times this weight into the button crucible. The bronze casting process will be detailed in part three (The Shed issue 105).
It is also useful to affix three wax stumps to the bottom of the button cup crucible to raise it above the base of the furnace when the bronze is melting.
Tools and materials you will need: long and short tongs; a grate; bricks; brushes to apply slurry; leather gloves; mask; LPG gas burner; hose and regulator; pot for the wax to fall into; pieces of bronze; a small piece of charcoal; the ceramic shell materials listed below.
Ceramic shell materials, formulas, and process overview
The process involves washing and drying the sprued wax sculpture and the button cup crucible then coating them both twice with slurry one and fine Molochite 50-80 or black magnetite. Ensure the layers are completely dry in between coats.
