Lost wax casting
A technique adapted from metalworking. The object to be fashioned in glass is modeled in wax and encased in clay or plaster that is heated. The wax melts and is released through vents or “gates,” also made of wax, which have been attached to the object before heating. The clay or plaster dries and becomes rigid. This then serves as a mold, into which molten or powdered glass is introduced through the gates. If powdered glass is used, the mold is heated in order to fuse the contents. After annealing, the mold is removed from the object, which is then finished by grinding, fire polishing, or acid etching.