Cactus leaf piece mold (3 of 4), circa 1910s-1970s

Piece mold used to make cactus leaves out of wax for exhibits, possibly between the 1910s and the 1970s.

Piece molds can be made of two or more pieces. The two or more pieces of the mold form a receptacle into which wax is poured through a funnel-like gate cut in the plaster. For cactus and larger leaves wax cloth is not used, instead hot wax is poured directly in the mold, which had to be previously placed in hot water to expel air from the plaster. Many wires were used not only as a midrib but as additional support for the heavy mass of wax.

Every joint of cactus is a facsimile reproduction of the original. Before making the plaster molds, every one of the hundreds of spines was carefully removed. After the casts had been taken from the mold they were colored from field studies of growing plants, and the original spine was then set in their proper place.