The Lost Wax Process

The following is the step by step process of the “Lost Wax Casting” method in a nut shell. This process normally takes about 4 to 6 weeks to complete a single sculpture. There is a lot of time and labor involved in each piece, each bronze is hand finished once in wax and then again in bronze. Watch the slideshow to see the process from start to finish.

 1. Making the Mold: A rubber mold is carefully created over the sculpted clay to capture all the detail which appears on the sculpture. A mother mold of plaster is built on top of the rubber mold to preserve the form.

2. Wax Casting: Molten wax is poured into the mold to form layers of wax. This wax model is an exact duplicate of the original casting.

3. Chasing & Spruing: The wax is pulled from the mold and hand chased by a skilled artisan. Wax rods and a pouring cup are attached to the wax to insure a successful pour.

4. Ceramic Mold: The wax casting is dipped into a slurry of silica and then into dry sand. This step is repeated several times to create the ceramic mold.

5. Burn-Out & Casting: The ceramic mold is placed in a kiln and fired. The mold bakes and the wax is “lost” from the mold to create a hollow ceramic shell – thus the term “Lost Wax.”  The ceramic shell is removed from the kiln and immediately the 2100° molten bronze is poured into the shell.

6. Chasing:  After the cooled bronze is removed from the shell the sculpture is refined and passes through strict quality checks to ensure a perfect result.

7. Patina: After bead blasting, similar to sandblasting, the bronze is ready for patina. The raw bronze sculpture is heated to specific temperatures and chemically treated to achieve controlled colorations of the metal.

Joshua is applying sulfur oxide to the bronze at an early stage of the Patina on the right. Check out Freedom online here