Patent ID: 7137432

Claim:
A method of casting a metal part, said method comprising the steps of: forming a sand-shape with a sand-forming apparatus comprising a core box comprising a cavity having a shape corresponding to a desired sand-shape, and a blow tube assembly comprising a sand passageway through which sand is blown into the cavity, a catalyst passageway for introducing catalyst into the sand blown into the cavity, and a seal between the sand passageway and the catalyst passageway, whereby sand in the sand passageway is isolated from catalyst in the catalyst passageway, wherein the blow tube assembly comprises an inner tube and an outer tube, which at least partially surrounds the inner tube, said forming step comprising the steps of: converting the apparatus to a sand-blowing state, whereat the sand passageway communicates with the cavity in the core box; blowing sand into the cavity; converting the apparatus to a catalyst-introducing state, whereat the catalyst passageway communicates with the cavity in the core box; and introducing catalyst into the sand blown into the cavity; casting the metal part, this step comprising pouring molten metal into or around the sand-shape; and removing the sand-shape from the metal part.