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The Fine Art Investment Casting Process (In a Nutshell)

2021-06-10

Artists start the investment casting process by creating an original model from clay or wax. The model is then covered with a durable and flexible mold material like silicone, latex, or polyurethane rubber to create an inner mold. This mold material captures all of the fine details of the original model. Once the inner mold hardens, an outer layer of plaster, silicone or fiberglass is placed around the inner mold to ensure the mold correctly holds its form. Melted wax is then poured into the mold, gradually coating the inner surface. This process is repeated until the desired wax thickness is reached. After the wax hardens it is removed from the mold. The mold can be re-used to duplicate the piece as many times as needed.

The wax copy is then sprued to provide channels for burning wax, air and molten metal. Once sprued, the wax copy is covered with several layers of sand and slurry to create a sturdy mold. Once the mold layer is solid, the piece is placed into a kiln, burning the wax away. This leaves a negative image of the final piece within a sand and slurry shell.

Without sufficient kiln heating, contact with molten metal will crack this shell under the stress of thermal shock.

The empty shell is then filled with molten metal, usually bronze. The bronze piece gradually cools and solidifies, after which we carefully remove the shell.

Finally, sprues are removed and any finishing touches, like polishing, are applied. The high accuracy of Lost Wax Casting eliminates the need for extensive machining in most applications.

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