The Lost-Wax Process

All of Timothy Schmalz’s bronze sculptures are created using a method called the lost-wax process. This method was common in the 3rd millennium BC and has changed little since then.

Clay Model
The first step of the process is to make a sculpture from clay. Over days, weeks, and sometimes months, details are added and refined until the piece is perfect and ready to be cast in bronze.

Creating a Mold
Multiple coats of liquid rubber are used to completely cover the clay piece. For large sculptures, sections are created for ease of handling. When the rubber process is complete and pulled off the clay, a negative image is created.

Wax Pour
The next step in the process is for melted wax to be poured into the rubber mold. The wax completely coats the inside of the mold. The wax forms a new positive image of the original sculpture.

The wax is then dipped in a liquid plaster mixture to create a hard plaster shell over the wax that will withstand the heat of molten bronze. It is then covered with sand and left to dry.

The wax is then dipped in a liquid plaster mixture to create a hard plaster shell over the wax that will withstand the heat of molten bronze. It is then covered with sand and left to dry.

Metal Pour
Once the plaster shells are dry, the wax inside can be melted, creating a negative image inside the shell. The molten bronze, heated to 1675° F, is then poured into the shell.

After the bronze cools, the shell can be removed and each section can be assembled like a puzzle. They are welded together until the entire bronze piece is complete and ready for a final check over each detail.

Patina
The Patina or ‘coloration’ is added to the bronze surface by a chemical spray for both beauty and protection.

Ready to Install
At last, the final bronze sculpture is complete and can be
installed in its permanent location and enjoyed for all to see for hundreds of years.