Abstract: A method for making expandable foam patterns for use in an evaporative casting process includes assembling a plurality of mold parts of a molding tool having mold walls defining a mold cavity, each mold part having a housing wall separated from the mold wall to form a heat exchange cavity adjacent the mold wall, inserting at least one heat pipe adjacent a mold wall portion, filling the mold cavity formed by the mold parts with expandable foam beads, heating the tool by introducing a fluid heat exchange medium to the heat exchange cavity to heat the cavity for a predetermined time, cooling the tool and separating the mold parts to release the expanded foam pattern.

Abstract: A method is disclosed of making dimensionally stable, expanded polystyrene foam patterns comprising: (a) expanding a supply of beads comprised of polystyrene and a thermally responsive expanding agent, the expansion being accomplished in one or more stages by use of a gaseous heating agent (steam) to define a fused pattern body of the expanded beads, and (b) subjecting the fused pattern body to subatmospheric pressure (in the range of 5-20" of Hg) for a period of about 0.5-6 hours but no more than sufficient to accelerate and complete the migration of the trapped expanding agent out of the pattern body. The expanding agent can be selected from the group consisting of various forms of pentane or butane.

Abstract: A method for contact fusion bonding of compressible, low density thermoplastic parts is disclosed, which comprises essentially: (a) fluidizing only a surface film on opposed mateable margins of the thermoplastic parts by precompressing the margins against a transversely stationary heated platen located therebetween and, prior to fluidization, continuing such contact to promote such fluidization by thermal conductivity and make heat-settable a limited, predetermined, nonmelted subsurface layer of said mateable margins; and (b) within a time period during which said surface films remain fluid, withdraw said platen from between said opposed margins with minimal separation while bringing the mateable margins together with sufficient force to merge said fluid films and compress said subsurface layers a predetermined moulded dimension.

Abstract: A method is disclosed of dehydrating a thin water based ceramic slurry coating on a foam pattern assembly having hidden internal surfaces. The method comprises sequentially subjecting the coated assembly to a first warm air flow at a sufficient temperature and time to dehydrate and remove 60-80% of the water of the coating, and secondly subjecting the dehydrated coating assembly to low level microwave energy to substantially remove the remainder of the water in all of the coating, the dehydrated coating being devoid of bubbles or cracking.The coating is made by use of a slurry comprising a thixotropic silica water suspension with the silica comprising only 40-50% of the slurry; the slurry also may include a small portion of clay and in some cases an acrylic or epoxy glue additive. The pattern assembly or cluster is comprised of a plurality of molding patterns integrally carried by a gating system and common sprue, the patterns being at least four in number and radiating from the common sprue.

Abstract: The invention is a method of reclaiming sand used in a method of casting a metal having a liquidus temperature below 2000.degree. F., the casting method using a vaporizable pattern set within a mold constituted of unbonded sand. The method comprises: (a) blowing, after a predetermined lapse of time after the pouring of the metal into the mold, a combustion supporting gas into and through substantially the entire volume of the mold to levitate at least a region of the sand adjacent to the casting and to combust volatilized byproducts of the pattern entering the mold, and (b) continuing the blowing of the combustion supporting gas to continue combustion and driving of the gas and byproducts of the combustion out of the mold.

Abstract: A method of making a composite consumable pattern for use in the cavityless type of metal casting is disclosed. At least two mateable pattern parts are formed entirely of a low density expanded closed-cell polymeric material which is ignitable upon contact with molten metal. The parts are brought together with predetermined mateable surfaces in contact under a pressure of 5-10 psi; one of the parts is vibrated with a frequency of 120-240 cycles per second and an amplitude of 0.03-0.10", to promote a controlled friction at the interface. A predetermined depth of the parts is melted and merged to create a water-tight bond between the mating surfaces upon relief of the vibration.