Abstract: An assembly for making a wax pattern of a hollow component includes a pattern die and a noncircular core which is located within the pattern die. The pattern die is a split die and includes two halves which have shaped internal surfaces to define the external shape of the wax pattern of the hollow component. The core has shaped external surfaces which define the internal shape of the wax pattern of the hollow component. The core has coaxial circular cross-section projections which locate within correspondingly shaped and dimensioned apertures in the pattern die. One of the apertures in the pattern die has a radially extending pin which is arranged to mate in a groove on the projection to locate the core longitudinally. The core is allowed to rotate within the die so that chaplets on the core position the core accurately without imposing strains on the core.

Abstract: The invention relates to a method of producing near net shaped metals parts from shaped wax patterns and more particularly a process whereby control of the wax pattern shape from which metal parts are to be investment cast is accomplished by machining the wax pattern after injection forming. The present invention incorporates a precision machining step whereby the injection formed wax is machined to dimensional values which more closely result in a near net shape of the cast metal part.

Abstract: In an improved method and apparatus for investment casting, a pattern (31) is mounted on a sprue base (19) of an spider gasket (12) that is secured to one end of a standard investment flask (11). A solid end cap (13) is secured to the other end of the flask. The end cap is provided with a matrix of holes (15) extending therethrough parallel to the axis of the flask, and a plurality of small diameter rods (16) are slidable secured in the holes in the end cap. The rods are extended into the interior of the flask about the pattern without contacting the pattern. Investment plaster (10) is poured into the flask through the spider assembly to immerse the pattern and rods, and the plaster is allowed to set. The rods are then withdrawn, forming a large plurality of channels (32) extending into or through the investment plaster, reducing the amount of investment plaster required in the flask. The channels greatly accelerate the drying time of the investment, and hasten the subsequent burnout process in a kiln.

Abstract: A method for forming a metal matrix composite within a mold of investment material. The method comprises the steps of forming a preform mixture of liquid flow medium, binding agent and reinforcement into the desired shape of a metal matrix composite. Then, allowing the preform mixture to solidify into desired shape. Next, encasing the preform mixture within a container of investment material. Then, heating the preform mixture at a controlled rate which first allows any fluid, such as water, to evaporate, then allows removal of the flow medium. Next, sintering the remaining reinforcement material and binder to form a solid preform. Then, disposing molten metal on top of the solid preform within the container such that the molten metal forms a seal with the container. Next, pressurizing the molten metal such that it is forced into said preform. Next, solidifying the molten metal to form a metal matrix composite in the shape of this preform; and removing the investment material from metal matrix composite.

Abstract: A method of evaporable foam casting of metal articles, such as engine blocks for internal combustion engines. An evaporable foam pattern having a configuration proportionally identical to the article to be cast is positioned in a mold and a finely divided flowable material, such as sand, surrounds the pattern and fills the internal cavities of the pattern. A molten hypereutectic aluminum-silicon alloy containing 16% to 19.5% by weight of silicon and containing a magnesium content in excess of the magnesium solid solubility limit, is fed into the mold and into contact with the pattern. The heat of the molten metal vaporizes the pattern, with the vapor being trapped within the sand and the molten metal filling the void created by vaporization of the pattern to provide a cast article. The high magnesium content in the alloy produces in the solid state a Mg.sub.

Abstract: The shape-dictating surfaces of the pattern are constituted by a thin self-supporting shell (4 & 5) of photocured polymer. The shell is produced by a laser controlled by a computer with reference to a design drawing. The inside of the shell is packed full of low melting-point modeling compound. The areas (6 & 7) of the pattern that do not dictate shape are demarcated by the low melting-point modeling compound.

Abstract: A method of casting metal using evaporative pattern casting process patterns in combination with a fixture for creating and maintaining a desired configuration in flexible patterns. A pattern is constructed and gently bent to the curvature of a suitable fixture. String or thin wire, which burns off during casting, is used to tie the pattern to the fixture. The fixture with pattern is dipped in a commercially available refractory wash to prevent metal adherence and sticking to the fixture. When the refractory wash is dry, the fixture and pattern are placed in a flask, and sand is added and compacted by vibration. The pattern remains in position, restrained by the fixture. Metal that is poured directly into the pattern replaces the pattern exactly but does not contact or weld to the fixture due to the protective refractory layer. When solid, the casting is easily separated from the fixture. The fixture can be cleaned for reuse in conventional casting cleaning equipment.

Abstract: A plastic model pattern indicative of the desired completed pattern having prescribed dimensional tolerances and surface finish characteristics is encased within a Type I material which may be a soluble wax or low melting point material, and subsequently leached from the Type I material to define a cavity corresponding to the dimensional characteristics of the plastic model pattern. A Type II material, such as an insoluble wax or high melting point material, may then be injected into the cavity to recreate the plastic model pattern without the use of any plastics materials, to avoid potentially mold deteriorating expansion of such plastics materials. The mold form of Type I material may then be removed by leaching, melting or the like to reveal the completed expendable pattern usable in a lost wax mold forming process. An injection apparatus and die structure is advantageously utilized in conjunction with the process to achieve high production quality and insure proper formation of the expendable pattern.

Abstract: An implant is produced with an open-celled structure at least partly covering its surface. The method uses a positive pattern having a basic pattern with particles bonded to it, the particles covering the areas of the pattern which correspond to the structured surface areas of the implant. The method uses the usual steps of conventional lost positive casting techniques. Importantly, the particles have a base with four to eight pins extending radially from its surface with at least three being connected to the basic pattern (e.g., by adhesive).

Abstract: A method for forming a metal matrix composite within a mold of investment material. The method comprises the steps of forming a preform mixture of liquid flow medium, binding agent and reinforcement into the desired shape of a metal matrix composite. Then, allowing the preform mixture to solidify into desired shape. Next, encasing the preform mixture within investment material. Then, heating the preform mixture at a controlled rate which first allows any fluid, such as water, to evaporate, then allows removal of the flow medium. Next, sintering the remaining reinforcement material and binder to form a solid preform. Then, forcing molten metal under pressure into said preform. Next, solidifying the molten metal to form a metal matrix composite in the shape of this preform; and removing the investment material from metal matrix composite. Additionally, there is a method comprising the steps of connecting a preform, which has been previously prepared for infiltration of molten metal, to a sprue system.

Abstract: In connection with a device for casting lead grids for electric battery plates, a highly porous ceramic mold lining, preferably of zirconium oxide, is prepared by flame-spraying. Such a lining can include a thin surface coating on a profiled, basic metallic mold or a separately prepared insert plate which is retained to a metallic mold molder. The ceramic surface coating may be accurately formed in place, or may be formed as an over-spray which is then reduced in thickess. Formation of the surface coating may be accomplished by placing masks on the basic metallic mold during the flame spraying, for those areas of the grid which tend to accumulate material, or by adjusting an initially coarse profile of the ceramic layer to the exact profile of the casting by a material-removing treatment.

Abstract: An improvement to the process for the lost-foam casting of metal articles. According to the process, the casting takes place under a controlled pressure which initially increases at a rate between 0.003 and 0.3 MPa for a first period of at most 5 seconds from the begining of the rise in pressure. The pressure then increases during a second period at a rate higher than the rate of increase during the first period, until the maximum desired pressure is attained.

Abstract: An expendable pattern of an article to be cast comprises a meltable material that expands upon heating (e.g., a wax pattern). The pattern is invested with particulate mold material to form a thin, layered shell having a wall thickness not exceeding about 0.12 inch. The thin shell wall thickness unexpectedly reduces damage and distortion to the shell during removal of the pattern therefrom by steam autoclaving. After firing, the thin gas permeable shell mold is surrounded by a refractory particulate support media in a vacuum housing. The vacuum housing is then evacuated to evacuate the mold cavity defined by the thin shell and concurrently a pressure is applied to the support media so as to compress the support media about the thin shell to support the shell against casting stresses when molten metal is countergravity cast into the evacuated mold cavity.

Abstract: A turbine engine component includes an annular array of airfoils which extend between inner and outer shroud rings. In order to accommodate thermal expansion of the airfoils, space is provided in a shroud ring rail. To provide space in the shroud ring rail, core material is positioned at the ends of the airfoils. The core material may be preformed separetely from the airfoils or may be a coating which is applied to end portions of the airfoils. Wax pattern material partially encloses the end portions of the airfoils and core material. The shroud ring pattern and the core material are covered with ceramic mold material to form a mold. The shroud ring pattern is then removed from the mold to leave the core material disposed in the shroud ring mold cavity at the end portions of the airfoils. As the mold is preheated, bonds between the core material and the airfoils are broken and the core material is gripped between end portions of the airfoils and the ceramic mold material.

Abstract: A pipe section, especially an elbow pipe section, is cast to have an internal heat insulation lining so that the pipe section can withstand temperatures up to about 2500.degree. C. The internal heat insulation is first formed as a hollow casting core of carbon fiber composite material which, after curing, is inserted into a casting mold to function as the casting core which then becomes the internal heat insulation of the pipe section as the result of the casting of the pipe section, whereby the carbon fiber composite material is bonded to the interior surface of the pipe section.

Abstract: Open-celled metal structures are produced which have walls and webs of uniform strength throughout. The structures may also have an irregular surface pattern. To make a strengthened positive pattern, the method comprises application of at least one layer of a strengthening agent such as poly(methyl methacrylate) or polyester resin to a plastic substrate used for ceramic mold formation. The strengthened positive pattern is embedded in a ceramic mass, and heated to incinerate and remove the plastic substrate, which results in voids in the ceramic mass. Molten metal is poured into the ceramic mass. After solidification, the ceramic mass is removed to form the open-celled metal structure.

Abstract: The tube is at least two inches long and has successive sections of progressively smaller diameters to produce a correspondingly shaped sprue passage communicating with a pattern cavity in a casting investment, so that fluid casting material passes with increasingly fluid velocity between an inlet and outlet of the sprue passage during the casting process. A bulbous portion of the tube is spaced from its free end, to form a reservoir chamber in the sprue passage, spaced sufficiently from the pattern cavity, so that casting material flowing through the sprue passage attains maximum velocity at the outlet of the passage entering the pattern cavity.

Abstract: A method is disclosed for the casting of metals by the use of a consumable or evaporative pattern. In this method, a foamed pattern of a desired part is first formed. The pattern is then dipped into a ceramic slurry and the slurry dried in order to form a shell containing the foamed pattern. A heated bed of a particulate medium is formed around the ceramic shell which causes the pattern to evaporate and form a mold. A molten metal is then introduced into the mold, solidified and removed from the mold to form a casting.

Abstract: A method for designing and constructing component part removable partial dentures comprising designing the removable partial denture in tooth-supported and tissue-borne components provided with mechanical locks, waxing the design onto an investment model, casting the components, finishing the components, fitting the components onto a master cast, and locking the components together on the master cast or in the patient's mouth to form a single rigid unit using visible light cured resin around and over mechanical locks cast into the frame components.

Abstract: A novel sprue is used to cut wax and obtain the impressions of finger or other digit prints in a quick and effective manner. The sprue has an elongated handle connected to an impression plate having walls on its perimeter which cut easily through thin layers of wax when downward pressure is applied on the bottom of the impression plate. Then the wax is heated by a heat lamp until the top surface is melted at which time a finger or digit is placed on the wax and with downward pressure applied until an impression of the fingerprint or other digit print is left in the wax. After the wax is cooled then the impression can be imparted in gold or other metal jewelry by standard jewelry casting techniques. The result of this method is a memento that can be attached and worn as a necklace, bracelet, ring or other item of jewelry.

Abstract: A turbine engine component having an annular array of airfoils disposed between inner and outer shroud rings is made by a method which includes molding bodies of positioning material around central portions of the airfoils. The bodies of positioning material are placed in an annular array. Inner and outer shroud ring pattern dies cooperate with the bodies of positioning material to form inner and outer shroud ring pattern mold cavities. Pattern material is injected into the inner and outer shroud ring pattern mold cavities. The pattern material engages the airfoils, the positioning material, and the shroud ring pattern dies. The pattern material is solidified to form one piece annular inner and outer shroud ring patterns. The shroud ring patterns are covered with a ceramic mold material to form a mold. The inner and outer shroud ring patterns are then removed from the mold to leave shroud ring mold cavities.

Abstract: The ceramic core is located within the ceramic mold by the insertion of recrystallized alumina pins through the wax encasing the core prior to encasing the whole in a ceramic slurry; on the subsequent removal of the wax, the molten metal, i.e. superalloy, is injected into the resulting space; the recrystallized alumina pins remain intact during the casting process hence substantially increasing the success rate of achieving accurate core locating during casting solidification.

Abstract: The apparatus comprises two containers, which are adapted to be connected to a vacuum pump. The upper container contains a rotationally symmetrical guiding body. A distributing space is defined by the shell of the upper container and the closed peripheral surface of the guiding body and extends from the cover of the upper container to pipe lengths, which terminate at their lower end over cups arranged in the lower container. As a result, the apparatus permits an economical making of molds in series and meets the requirements arising in practice regarding the batchwise processing of batches in quantities which vary within an extremely wide range.

Abstract: The conventional investment casting technique is modified to cast metal products where the product has one or more support portons and at least one feeding tube for feeding molten metal into the cast of the product comprising providing a source of molten metal, connecting at least one metal feed tube to the mold of the metal product to be cast, of forming a hole in each support portion wherein the hole in each support portion is much larger than the volume of metal that can be non turbulently transmitted in a deflected manner into the mold by the feed tube so that the metal poured nto the generally uniform cross section mold cools gradually so that the support portions of the cast metal products will have a generally homogenous composition without air bubbles or cracks which could weaken the product.

Abstract: Apparatus useful in forming a mold from a wax pattern in an investment casting process, the invention provides a loop element having arm elements which spiral downwardly from and inwardly of the loop element to a base element. Sprue pins mount wax patterns to the loop element in a casting process known as the "lost wax" technique, the apparatus of the invention being particularly useful in the environment of a dental laboratory for formation of crowns and the like of high density. The loop element and arm elements of the apparatus leave channels in the investment material on "burn out" which quickly accelerate a casting material, such as a metal alloy, into the formed mold or molds with a reduction of turbulence which results in fewer defective castings. The channel geometry provided by the apparatus provides benefits due to a lack of right angles or sharp corners which restrict the flow of casting material into the mold or molds.

Abstract: A ceramic shell mold and method of making the same. The ceramic shell mold includes a facecoat layer comprised of a first ceramic material. A plurality of alternating layers are formed overlaying the facecoat layer. The alternating layers are comprised of a second ceramic material and a third ceramic material, the third ceramic material having thermophysical properties different than the second ceramic material. The second ceramic material and the third ceramic material are preferably a zircon-based material and an alumina-based material, respectively. The resultant ceramic shell mold has a greater high temperature creep resistance than a shell mold formed solely from the second ceramic material or solely from the third ceramic material.

Abstract: A method of casting utilizing an evaporable foam system with a hypereutectic aluminum silicon alloy. The molten alloy is introduced into a mold in contact with an evaporable foam pattern formed of polystyrene, or the like. The heat of the molten alloy will decompose and vaporize the pattern and the vapor will enter the interstices of the surrounding sand, while the molten alloy will fill the void caused by the vaporization of the pattern. By casting the molten alloy into contact with the evaporable foam material, a more uniform distribution of primary silicon is obtained in the cast alloy and the heat of crystallization caused by precipitation of silicon crystals on solidification of the alloy will temporarily slow the solidification rate of the alloy, thus increasing the time for elimination of pattern residue vapors from the molten alloy.

Abstract: A casting mold for the production of muffles which serve for the conversion of wax models to metal, with the casting mold having a funnel shaper (1) which consists of a disk-shaped base plate (4), at the circumference of which a side wall (5) which stands vertical to the base plate (4) runs, and a cone (6) arranged in the center of the base plate (4), pipe-shaped, muffle ring (2) partially inserted into the funnel shaper (1), with the outside wall of the muffle ring (2) resting against the inside circumference of the side wall (1) of the funnel shaper (1), a cylindrical ring (7) which is inserted on the side of the muffle ring (2) which faces the funnel shaper (1) and the central opening (8) of which surrounds the cone (6), and a blind funnel (3) provided on the side of the muffle ring (2) opposite the funnel shaper (3), whose funnel tip faces towards the cone (6 ) of the funnel shaper (1).

Abstract: An improved turbine engine component includes an annular array of airfoils which extend between inner and outer shroud rings. In order to accommodate thermal expansion of the airfoils, cavities are provided in one of the shroud rings. The cavities may be formed by moving a shroud ring under the influence of forces applied to the shroud ring by a gating system. The cavities which are formed in the shroud ring to accommodate thermal expansion of the airfoils may be open-ended, completely closed-ended or partially closed-ended. When a turbine engine component having cavities in an inner shroud ring is to be formed, molten metal in an outer shroud ring mold cavity is first solidified to firmly grip outer ends of the airfoils. The molten metal in an inner shroud ring mold cavity is then solidified. As the molten metal in the inner shroud ring mold cavity solidifies, the gating system contracts to pull the metal in the inner shroud ring mold cavity inwardly relative to the airfoils.

Abstract: A turbine engine component includes an annular array of airfoils which extend between inner and outer shroud rings. In order to accommodate thermal expansion of the airfoils, space is provided in a shroud ring rail. To provide space in the shroud ring rail, core material is positioned at the ends of the airfoils. The core material may be preformed separately from the airfoils or may be a coating which is applied to end portions of the airfoils. Wax pattern material partially encloses the end portions of the airfoils and core material. The shroud ring pattern and the core material are covered with ceramic mold material to form a mold. The shroud ring pattern is then removed from the mold to leave the core material disposed in the shroud ring mold cavity at the end portions of the airfoils. As the mold is preheated, bonds between the core material and the airfoils are broken and the core material is gripped between end portions of the airfoils and the ceramic mold material.

Abstract: An iron metal traverse drum having extremely thin walls is formed by instantaneously injecting a molten metal into a limited cavity of a mold having a form corresponding to the traverse drum in an oxygen-free atmosphere.

Abstract: An investment compound for use in a precision casting mold comprises MgO powder and Al.sub.2 O.sub.3 powder as main constituents in such a manner that the MgO powder and/or the Al.sub.2 O.sub.3 powder are or is in the range of 100 .mu.m or less in grain size and of 10% or more in weight precent, whereby even when a high-temperature active casting material such as titanium is used, the material provides a casting having a very beautiful surface with no bubbles formed therein and can positively compensate for shrinkage due to the solidification of cast material in a lost-wax process and can advantageously provide the casting at lower prices.

Abstract: Pattern material, such as wax, is removed from an investment casting mold by vapor phase-condensation heating with a fluorochemical boiling at a temperature above the melting point of the pattern material.

Abstract: A process for preparing an investment casting mold is provided. A kneaded compound composed of an aggregate and an organic binder is cast into a core molding mold to be solidified therein to produce a core matrix which is impregnated with a heat resisting binder to an appropriate depth followed by coating with a wax, whereby a core mold is formed. The core mold is placed in position within a lost model molding mold followed by injection of a lost model forming material. A slurry and stucco particles are alternately coated over the lost model for plural times to form a refractory layer. The lost model is removed to obtain a final mold which is baked to effect simultaneous baking of the core mold and the refractory layer, the former forming the mold core and the latter forming the exterior shell mold.

Abstract: A core mold to be assembled with a shell mold for use in an investment casting process is provided. The core mold comprises a core matrix essentially consisting of an aggregate and an inorganic binder, a binder layer impregnated from the surface of said core matrix, a coating layer formed by coating a slurry over said binder layer, and a paraffin wax layer covering the exterior periphery of said coating layer. Also provided are a process for preparing the core mold and a process for preparing an investment casting mold in which the core mold is assembled.

Abstract: The forming of a wax or sacrificial pattern for investment castings in which the interior ceramic reinforced passageway forming elements are reinforced with a metallic wire, and sheathed in a quartz material is disclosed. Thereafter the wire and quartz serve as a reinforced core around which the ceramic is molded to the configuration of the passageway, and in addition containing the positioning elements for mating engagement with the wax injection die at each end of the passage forming part. The method of forming the pattern for injection molding involves the steps of first determining the passage locations, and thereafter forming a reinforced passage ceramic forming member to be positioned interiorly of the pattern. The wax injection die is formed with mating elements to support the ceramic passage forming members. Thereafter the mold is filled with sequential layers of ceramic, and fired.

Abstract: A method of manufacturing a composite chip-removing tool which includes a tool body of a material which is in its molten state above a predetermined melting temperature, and at least one tipping element secured to the tool body, comprises positioning the tipping element on a model of the tool body that consists of a material that melts at a temperature considerably lower than the predetermined melting temperature, in a position relative to the model which the tipping element is to assume relative to the body, and simultaneously forming the tool body and a durable mechanical connection of the tipping element to the tool body in a precision casting operation involving replacement of the material of the model with the material of the tool body in its molten state. The model may be produced prior to or simultaneously with the positioning of the tipping element on the model.

Abstract: A method of investment casting utilizes a pattern produced by stereolithography in which a three-dimensional specimen is provided by light cure of ethylenically unsaturated liquid material. The stereolithography composition is constituted by the ethylenically unsaturated liquid material in admixture with an inert low thermoplastic material which weakens the pattern when heated within the mold used in the investment casting process to prevent the thermal expansion of the pattern from cracking the mold.

Abstract: Apparatus for molding hollow metalwood golf club heads of wax or other material with variations in the lie angle of the neck or hosel relative to the body of the club head, in which two molds with communicating mold cavities are supported for turning of one mold about a pivotal axis to change the angular relationship of the two cavities. The molds have arcuate abutting surfaces coaxial with the pivot for effective meeting relationships in the different positions, the hosel base being slightly oversize to accommodate the displacement, and two core pieces in the molds have part-spherical abutting surfaces, also coaxial with the pivot for effective "kissing off" of the parts. The movable mold is detented in one of eight different positions, in one-degree increments. Another embodiment produces solid-headed irons with selected different lie angles of the hosel, but with only one core piece, which is in the hosel mold.

Abstract: The present invention relates to a mold material for casting pure titanium or a titanium alloy which comprises one or more chief materials selected from among silica-alumina mixtures, mullite and spinel and a hardening agent comprising a phosphate and a basic metal oxide and a process for casting pure titanium or a titanium alloy by the use of said mold material. This mold material forms a refractory structure having a melting point higher than that of pure titanium or a titanium alloy therein to enable pure titanium which is unstable in a molten state to be cast stably.

Abstract: A cushioning sheet made of a flammable material for use, e.g. in denture casting. It is inserted into a casting frame and adapted to burn out when heated to leave a space between a casting frame and a casting mold in the frame. The space serves to absorb the difference in the thermal expansion between the frame and the mold, thus preventing the casting mold from cracking or breaking. The cushioning sheet is formed with apertures. The casting material penetrates through the apertures, abutting against the casting frame to support the casting mold upon the frame even after the cushioning sheet has burnt out.

Abstract: The pins which are used for the support of a core in a lost wax casing process are provided with caps. The caps provide sufficient surface area for encapsulation by ceramic slurry. Heat loss from the metal melt via the pins is thus obviated along with undesirable grain nucleation.

Abstract: A mold is made from a flute chimney model having a precision bore, and a chimney is cast from the mold with substantially no shrinkage in bore diameter. The mold can be made from a chimney model having an entire undercut surface thereon, and the chimney cast with substantially no shrinkage in undercut diameter.

Abstract: A method of forming a bezel that contacts and/or substantially envelops a gem without altering the same is presented. A replica of the gem is initially formed about which a temporary bezel is crafted having the desired artistic markings thereon. In a lost wax process, the temporary bezel is replaced by a permanent bezel. Then the replica is destroyed. In another aspect of the present invention, a replica mold material for use in this process is also disclosed.

Abstract: The invention concerns a composition for making a coating consisting essentially of a refractory material selected from the group consisting of yttrium oxide, zirconium oxide, fused yttrium oxide, fused zirconium oxide, fused stabilized zirconium oxide, and fused mixtures of zirconium oxide and yttrium oxide; and a sufficient amount of an yttria sol binder. The composition can be used to prepare refractory materials, casting and core molds.

Abstract: Improved small dendrite arm spacings and good technical values, regarding the technical properties of aluminum alloys, particularly tensile strength, yield strength and elongation percent, can be reliably obtained by refining the grain of the casting to provide the smallest possible spacings between the secondary dendrite arms, by casting the aluminum alloys in a ceramic mold provided with numerous micro-sized rough spots and pores and to the inner wall of which mold after it is dried and fired has been applied a thin layer of a salt mixture in which the cations are primarily from the alkalis and/or alkaline earths and the anions are primarily from halogens and which applied salt mixture has a liquidus temperature lower than the casting temperature of the alloy.

Abstract: The sand-binder mixture in a sand casting mold is controlled so that it contains sufficient binder to enable it to set to form a mold, yet the resulting set mold is sufficiently porous to receive liquids and vapors from a disposable pattern and sufficiently rigid to retain the pattern shape after the pattern is removed. At the proper binder loading, the mold has porosity such that the pattern will evacuate the cavity prior to casting when heated at relatively low temperatures (well below pattern combustion temperatures) that do not harmfully affect the mold and do not necessarily remove all of the pattern material from the mold. Thus, the pattern is removed from the mold cavity, before the molten metal is added, by heating the pattern and mold to cause the pattern to become fluid and to flow both into the sand mold and out of openings in it, without the need for high temperature combustion. The molten metal is then added to the cavity, and allowed to solidify before it is removed.

Abstract: A method for selectively coating inexpensive accessories with expensive multi-metals sequentially by utilizing an apparatus of a cylinder member, standing member, wax rod, and glass housing for producing fine products which are coated with colorful expensive multi-metals.

Abstract: Time-consuming steps of drying the unhardened and porous refractory dental model, hardening the dried model, and applying multiple coatings of a lacquer spray onto the hardened model are eliminated by spraying the unhardened and porous model with a non-viscous solution of specified cyanoacrylates to thereby produce a final model which yields a mold providing an improved alloy casting dental prosthesis.

Abstract: An improved sprue pin for producing castings by the lost wax method wherein the sprue pin gradually decreases in external circumference toward the tip of the sprue. The length and gauge of the sprue is such that it provides acceptable flow rates and solidification times for new base metal and palladium alloys. A set of lines about the circumferentially decreasing tip allows the user to conform the sprue to the size of the wax pattern being used to form the casting.