A crucible for melting material includes at least one wall at least partially enclosing a volume and including an orifice through a portion thereof, and a chill plate supported for movement between at least a first position covering the orifice and a second position. The chill plate is configured for removal of heat from the at least one wall when in the first position. Some crucibles include a substantially flat bottom plate, a plurality of hollow tubes above the substantially flat bottom plate proximate a periphery thereof, and a plurality of O-rings. Each hollow tube is in contact with at least one O-ring, and each O-ring is in contact with the substantially flat bottom plate. A method includes moving the chill plate, initiating flow of molten material, terminating flow of molten material, and replacing the chill plate. Flow of material may be controlled by providing a vacuum in the crucible.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
 This invention was made with government support under Contract Number DE-AC07-051D14517 awarded by the United States Department of Energy. The government has certain rights in the invention.