Core-Forming

Or core technique. The use of a removable core around which the glass is formed. Traditionally, the core is made of an organic compound (i.e., animal dung), mixed with a binding agent (often clay). The core is fixed on one end of a metal rod and provides the interior shape of a glass vessel. Rod forming is the similar technique, that is used in bead making, but it is distinguished by a thinner core. Melted glass is wound around the core.