Abstract: A method for casting metal using a semi-permanent mold connected to a feed portion includes forming a coolant jacket in a sprue of the feed portion. A coolant source is connected to the coolant jacket. A metal in a molten state is poured into the feed portion for gravity induced flow into the semi-permanent mold. A wall thickness of the sprue is predetermining which minimizes heat transfer from the sprue, thereby forcing the metal in the molten state to cool slower in the sprue than in the mold. After a predetermined time for the metal to cool to a solid state in the mold, flow of a coolant from the coolant source into the coolant jacket is initiated to cool the metal in the sprue before opening the mold.

Abstract: A method for casting metal using a semi-permanent mold connected to a feed portion includes forming a coolant jacket in a sprue of the feed portion. A coolant source is connected to the coolant jacket. A metal in a molten state is poured into the feed portion for gravity induced flow into the semi-permanent mold. A wall thickness of the sprue is predetermining which minimizes heat transfer from the sprue, thereby forcing the metal in the molten state to cool slower in the sprue than in the mold. After a predetermined time for the metal to cool to a solid state in the mold, flow of a coolant from the coolant source into the coolant jacket is initiated to cool the metal in the sprue before opening the mold.

Abstract: Apparatus for the gravity-cast, “lost-foam” casting of metal castings, including a fugitive, pyrolizable foam pattern forming a casting cavity in a bed of loose sand, and a hollow sprue for supplying melt to the casting cavity, wherein the sprue consists essentially of the same metal as is being cast. A high-temperature, porous vent is provided adjacent the discharge end of the metal sprue to expel air from the sprue that would otherwise be trapped therein.

Abstract: Apparatus for the gravity-cast, “lost-foam” casting of metal castings, including a fugitive, pyrolizable foam pattern forming a casting cavity in a bed of loose sand, and a hollow sprue for supplying melt to the casting cavity, wherein the sprue consists essentially of the same metal as is being cast. A high-temperature, porous vent is provided adjacent the discharge end of the metal sprue to expel air from the sprue that would otherwise be trapped therein.

Abstract: Apparatus for the gravity-cast, bottom-fill, “lost foam” casting of metal castings, including a fugitive, pyrolizable pattern (for forming a casting cavity), and a hollow sprue (for conducting melt to the casting cavity) embedded in a bed of loose sand. The sprue is free from pyrolyzable foam and conducts melt from above the pattern to a gating system supplying melt to the pattern. The sprue is constructed so as to cause the melt to approach the gating system from beneath and keep any pyrolysis products from entering the sprue.