For casting and carving, mix equal parts of melted wax and clay. Plaster of Paris, if completely dry, can be used for casting lead and other metals. Boiled linseed oil makes the best adhesive for sand molds or castings, but molasses (any thick syrup) can be used. Plaster can be mixed with fiberglass or mortar sand, and plaster can be made tougher by boiling in wax, tallow, or milk. Paper mache is harder and more moisture resistant if made with plaster of Paris instead of flour paste. To make a plaster cast of a person’s face, first coat the hair with vegetable oil, insert tubes in the nostrils, and fasten a roll of cloth around the head to limit the spread of the plaster. Mix the plaster and apply about a ½-in. thick coating. When the plaster is hard, remove it, soak it in linseed oil, and use this negative for casting a positive copy.