Lost foam casting system with high yield sprue

A lost foam casting system (2) includes a sprue (8) have a receiving portion (56) for receiving molten metal (14) from a source (16), a distribution portion (58) with a plurality of radial fingers (59-62) for distributing the molten metal (14) radially outwardly, and a lower section (63) having a plurality of feed passages (35-38) receiving molten metal (14) from the respective radial fingers (59-62) and interconnected by thin flat support walls (39-42) providing a relatively rigid structure. Workpieces (18 and 20) and in-gates (23-25 and 26-28) are connected to the flat exterior surfaces (39 and 41) of the lower section (63) of the sprue (8) and fed with molten metal (14) from respective feed passages. The structure provides pattern assembly rigidity, excellent dimensional control, high casting yield, high ratio of casting weight to gating/sprue weight, high surface area to volume ratio facilitating escape of vapor and organic effluents, ease of pattern attchment by large outer flat sprue surfaces, accessibility of casting for ease in removal from the sprue, low total volume for reduction of buoyancy, and faster metal fill rates and faster cooling.