Glass casting a French commercial crystal manufacturer, produce highly sculptural pieces in pate de verre. Graphite is also used in the hot forming of glass. Graphite moulds are prepared by carving into them, machining them into curved forms, or stacking them into shapes. Molten glass is poured into a mould where it is cooled until hard enough to be removed and placed into an annealing kiln to cool slowly. Glass casting Glass casting is the process in which glass objects are cast by directing molten glass into a mould where it solidifies. The technique has been used since the Egyptian period. Modern
Metal spinning more involved process, known as "reducing" or "necking", allows a spun workpiece to include reentrant geometries. If surface finish and form are not critical, then the workpiece is "spun on air"; no mandrel is used. If the finish or form are critical then an eccentrically mounted mandrel is used. "Hot spinning" involves spinning a piece of metal on a lathe while high heat from a torch is applied to the workpiece. Once heated, the metal is then shaped as the tool on the lathe presses against the heated surface forcing it to distort as it spins. Parts can then be