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
Glass-to-metal seal grey-blue or grey-brown color indicates a good seal. A metallic color indicates lack of oxide, while black color indicates overly oxidized metal, in both cases leading to a weak joint. Molybdenum bonds to the glass via the intermediate layer of molybdenum(IV) oxide. Due to its low thermal expansion coefficient, matched to glass, molybdenum, like tungsten, is often used for glass-metal bonds especially in conjunction with aluminium-silicate glass. Its high electrical conductivity makes it superior over nickel-cobalt-iron alloys. It is favored by the lighting industry as feedthroughs for lightbulbs and other devices. Molybdenum oxidizes much faster than tungsten and quickly develops