The Lost Wax Process

1. The "lost wax" method of casting dates back thousands of years to ancient Egypt, Greece and Rome. It is still the best method for capturing exquisite detail in brass and bronze.
2. The first step, and most important, is to create a clay original model of the sculpture to be made into brass. All the detail and features that the artist wants in the finished piece must appear on the clay model. Care must be taken to capture the smallest of detail. Depending on the size of the sculpture, the mold is then cut into sections for casting.
3. Molten wax is then poured into the rigid mold. It is poured in layers to the thickeness desired in the finished piece. This wax model is an exact duplicate of the original casting. "Gates" or channels, made up of wax rods, are added to the model to insure an evenly distributed casting of the metal. The plaster mold is then placed in a pit of sand or similar material to hold it in place for the pour.
4. When molten brass is poured into the mold, the liquid metal burns out and replaces the wax model; thus, the lost wax part of the process. The metal then cools and hardens, forming an identical sculpture in brass.
5. The piece is then finished by hand. The gates must be cut off. The parts are welded together and much grinding, polishing and buffing must be done.
6. Many of the finished pieces are then given a rich verdigris patina to help protect the brass and add to its appeal.

See http://www.gardenartisans.com/lostwax.html