According to the material object unearthed from ancient bronze workshop site, and combined with the shape analysis of bronze ware, experts believe that most ancient Chinese bronze casting is produced by using paradigm casting method.
The process of paradigm casting can be divided into five steps.
1. Mold
Use clay to model the basic shape of bronze.
2. Turn
Push tightly the tiny soil that mediated in advance on the surface of the mud die. Flap to make the shape and decorative design back printed on mud chip.
3. Splice
Divide the turn-good clay into several pieces. Burn them to be ceramic. Cohere them together to form the external cavity of the container. Use the mud die in the second step to the internal surface. Get the two parts together. And the distance between the two parts is the thickness of the bronze ware.
4. Pouring
Inject the copper liquid into the pottery mould. When the copper liquid solidify, break the inside and outside mould.
5. Grinding and trimming
The bronze now is rough, and its grain is not clear. It needs to be grinded and trimmed. Then it will become a delicate copper. The common methods that used here have three ways. Fold casting is one of them. And it appeared in the Spring and Autumn Period and become popular in Han dynasty.
In the later period of Spring and Autumn Period, the Chinese might have invented the lost wax casting process, and it can be divided into three steps. First, use the wax to produce the wax mould, and use fine mud to spray some times to make it harden. Then bake burn it to be ceramic. At last, inject the copper liquid.Lost wax casting method often use to cast those bronze wares with complicated appearance. The copper Chu ban and the CengHouZun disk are both considered to use the method of lost wax casting.
