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The Pour
No part of the process surpasses the pour for drama and excitement. The incredible temperatures of the metal (approximately 1200 degrees for aluminum, 2100 degrees for bronze, and up to 2800 degrees for iron) mean that extreme care and precision must be exercised throughout the process. Protective equipment such as face shields, heat-resistant suits and a telephoto lens are also a must.
Ceramic shell molds are heated to 1200 to 1500 degrees while the bronze is melting. Metal flows farther, faster and thinner in a hot mold, as well as picking up greater detail.
Sand molds, often larger, are buried in a sand pit to prevent 'run outs' and insure they will fill. Sometimes we pull the metal through the mold with a vacuum.
When the metal reaches the desired temperature, depending on the thickness of the piece to be poured, the crucible is lifted from the furnace by the crane.
The pour pictured on left is a three-person operation, two people on the crucible, one handling the molds. One person pours, directing the deadman (who operates the hoist) "up, down, in or out". The mold handler selects the order of pour; thin ones first. Thicker pieces do not require the hottest metal
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