Metalworking in Bronze Age China: The Lost-Wax Process By Peng Pe ...

visualized in the negative. A model with a complex shape that would not permit the withdrawal of the mold in only two pieces would render the bivalve mold insufficient. How could this problem be resolved?

One solution to this problem was to increase the number of mold pieces. The shape of the design, if not exceedingly intricate, would permit the clay mold to be removed from the model in a controllable number of pieces, which would be reassembled later for casting. This method is called “section-mold” (short for “multi-section-mold”) or “piece-mold” (short for “multi-piece-mold”) casting. Referring to a diagram in figure 7, we could briefly illustrate how a three-legged vessel similar to that shown figure 9 might be made by the section- or piece-mold casting process in principle: the round tripod is modeled in clay or similarly manageable material; the mold is constructed against the model in multiple fitted sections; then the mold is peeled off and finally reassembled around a core, waiting for the pour of molten metal.⁵

An alternative solution to the problem exists. The complex shape of the design requires a model, but a mold is not easily separated from this model in two pieces; an ideal solution would allow for the creation of a casting cavity without detaching the mold. In this case, the model would necessarily disappear, whereas the undetached mold would have to remain in place to keep the casting cavity intact. How could this be achieved? The model would have to undergo a physical transformation that would allow it to be easily discharged from the enclosed mold––something like a fluid or gas. Once the model was “lost,” a hollow casting matrix would be formed within the mold to await the pour of the molten metal. 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. As a result, this method has been termed the “lost-wax” (or cire perdue) process; the idea of a “lost model” lies at the heart of this method. The clay mold, as an investment onto or enveloping of the model, need not be constructed in pieces, removed from the model, and reassembled. This method is also referred to as