Abstract: A vent-forming apparatus for use in metal casting comprises a gas-permeable membrane with a lead-in tube attached to one surface and a breather tube attached to the opposite surface. The vent-forming apparatus may be used to create independent vents in the walls of shell-type molds used in the ceramic shell casting process for lost wax casting of ferrous and non-ferrous alloys. These vents exhaust gasses in the mold cavity to the atmosphere. The vent-forming apparatus also may be used in solid mold investment casting methods or in any other casting method in which venting is desirable or necessary.

Abstract: This invention relates to a valve apparatus for use in metal casting and methods of its use. The valve apparatus according to this invention comprises a gas-permeable membrane with a lead-in tube attached to one surface and a breather tube attached to the opposite surface. The valve apparatus according to this invention may be used to create independent vents in the walls of shell-type molds used in the ceramic shell casting process for lost wax casting of ferrous and non-ferrous alloys. These vents exhaust gasses in the mold cavity to the atmosphere. The valve apparatus according to this invention also may be used in solid mold investment casting methods or in any other casting method in which venting is desirable or necessary.

Abstract: This invention relates to metal casting apparatus, methods and molds and more particularly to the casting of metal in refractory, gas-permeable, shell-type molds which are lighter and have thinner wall thicknesses than the refractory, gas-permeable, shell-type molds commonly used in the ceramic shell casting process for lost wax casting of ferrous and nonferrous alloys such as steel, aluminum, and bronze. As a result of the use of vacuum in the inventive apparatus and method, more complete mold fill out is achieved, resulting in better capture of exact detail and close tolerances in the finished cast object. Further advantage is derived from the fact that the casting of large objects is simplified and can be done more quickly. Also, there is an associated substantial savings in labor costs, materials costs and time. The inventive apparatus and method also can be used in the foam vaporization casting process of metal casting.