Artists will usually prepare multiple sculptures for bronze pours because they are hot work, labor intensive, expensive and require the help of several people. An independent artist like me might have just pour once a year and yield 12-20 finished sculptures. Creating a clay models for one sculpture, preparing a mother mold and then a wax model for bronze casting may take a month. The Investment Method can be completed in the home studio using common products. The Ceramic Method is used in professional foundries and an excellent method. However, it is not affordable e for individual artists.
- Start with a wax model of each sculpture (brown wax in photos).
- Invert the wax mold in preparation for the next steps. More than one wax model can be sprued together in the same mold
- Add sprues (red wax) to the model(s) for venting. Molds must have vents to allow the mold to fill with the hot bronze (2000 degrees).
- Add a funnel (white cup) for pouring hot bronze into the mold. A wire cage can be added to reinforce the investment plaster.
- Add a face coat of investment plaster (usually contains pre-fired waste plaster from prior pours called ludo).
- Add a sheet metal collar to contain the investment plaster. Keep the main sprue and the funnel at the top edge of the collar.
- Fill the metal collar with investment plaster.
- When plaster is dry, the molds are ready for the Burn-Out Kiln.
- Burn-out kilns are usually large so many molds can be prepared at the same time for a single upcoming pour.