Cire perdue Castings of Buarani By Chander P Mahajan Cire perdue , method of casting images in metal has had a long history of tradition and growth. The earliest examples of this method have been unearthed in the excavations at Mohenjodaro. The oldest known example of this technique is a 6,000-year old amulet from Indus valley civilization. Also called the Lost-wax casting, "investment casting", "precision casting", or cire perdue which has been adopted into English from the French is the process by which a duplicate metal sculpture (often silver, gold, brass or bronze) is cast from an original sculpture. Intricate works can be achieved by this method. A process used in metal casting that consists of making a wax model (as of a statuette), coating it with a refractory (as clay) to form a mold, heating until the wax melts and runs out of small holes left in the mold, and then pouring metal into the space left vacant. This technique is known as solid casting. A method of bronze casting using a clay core and a wax coating placed in a mould. The wax is melted in the mould and drained out, and bronze poured into the space left, producing a hollow bronze figure when the core is discarded.
The weight and expense of solid casting prohibit its use for large works. This lead to the development of hollow casting.
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It was found that it was possible to take moulds from a glyptic work by suspending a core form with core pins in between the moulds and by filling the interspace between the mould and the core with molten metal and obtain a hollow cast.
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The other technique is to shape a core form slightly smaller than the cast intended in metal and applying wax sheets equal to the intended thickness of the cast over the core form
Metal-chasing then follows. Just as the wax model was finished, the casting is worked until the telltale signs of the casting process are removed, so that the casting now looks like the original model. Pits left by air bubbles in the casting and the stubs of the sprucing are filed down and polished.