Lost-wax Casting Method in Chinese Bronze Ornaments

The earliest archaeological evidence of lost wax casting in China was found in the sixth century BC. The Cemetery of Chu State in Xichuan, Henan Province. Bronze Jin, cast using traditional piece-mold techniques, is further embellished by adding prefabricated ornate open worked handles, which are produced through a lost wax process and then attached. Lost wax was eventually introduced to China from the ancient Near East as far west as possible, and the process has an early and long history in the region, but exactly when and how it was introduced is unclear. The dewaxing process is more suitable for casting decorations with deep undercuts and openwork designs than the molding process, which complicates the removal of molded parts from the model. Although lost-wax casting was never used to make large vessels, it became more and more popular in the late Eastern Zhou Dynasty and the Qin and Han Dynasties. The lost-wax casting process for casting small parts was more economical than the mold-** process because the amount of metal used was easier to control.

In the “lost-wax” process, the object to be cast is first modeled. Wax, which is easy to shape and carve and which melts away under the proper conditions, has been the most commonly used material for this purpose since antiquity. The wax model is then coated with clay to form the mold. The first coat of clay is usually carefully brushed to prevent trapping of air bubbles; subsequent coats may be rougher. Then, the clay is fired and the wax melts (thus "lost wax"). Molten metal is then poured into the clay mold to replace the burnt wax model. After the metal cools, the fired-clay model is opened to reveal the finished product. The resulting cast object is a metal replica of the original wax model.