Kiln casting
Kiln casting is a way of making glass objects by melting glass into a mould inside a kiln. Pieces of glass or crushed glass, frit, are placed in or above a heat-resistant mould and heated until they flow and fill it. After annealing, the mould is broken away or washed out to reveal the finished piece.
It is used for thick, solid objects with detail, from sculpture to architectural panels, sometimes with a mould made by the lost-wax method. Cast glass can be made much thicker than fused sheets, so it needs long, slow annealing.
A related method, pâte de verre, uses a paste of ground glass and a binder pressed into the mould.