Abstract: A hopper for providing moulding sand having an opened top and a bottom member having through holes for discharging the sand is positioned spaced apart at a suitable distance horizontally from a cover member connected to a suitable source for generating gas for hardening the moulding sand. A pattern plate provided with vacuum evacuating means is disposed to be selectively connected to either one of the hopper and the cover member for discharging and filling the moulding sands into a flask placed on a pattern plate and for introducing hardening gas and allowing said gas to penetrate and permeate through the layer of sand filled in the flask to harden the filled sand, respectively. By using vacuum evacuation of a hollow chamber in the pattern plate instead of pressurized air and hardening gas under pressure, the entire moulding apparatus can be rendered lighter in construction and smaller in size, while any leakage of poisonous hardening gas can be completely prevented from occurring.

Abstract: Curable epoxy resin compositions are described which comprise a mixture of an acid curable epoxy resin and a minor amount of an oxidizing agent capable of reacting with sulfur dioxide to form a catalyst for curing said epoxy resin. The curable epoxy resin composition may contain solid particulate materials. The procedures for curing such epoxy resins as well as methods for forming sand cores and molds also are described. Sand cores and molds produced in accordance with the method of the invention have sufficient strength and hardness after a few seconds of curing for normal foundry applications.

Abstract: A core blowing machine receives match plates on a mounting surface so that a sand and bonding agent mixture may be packed about the match plate and exposed to a catalytic gas for forming a mold component. A support surface is disposed beneath the mounting surface. An auxiliary assembly includes an auxiliary mounting surface and an auxiliary support surface in substantially the same spatial relationship as the mounting and support surfaces. A support jack is placed on the auxiliary support surface and is adjusted in length to extend between the auxiliary support surface and a match plate mounted in the auxiliary assembly. Then the suppot jack is placed in a position on the support surface which is similar to the position occupied on the auxiliary support surface and the matching plate is disposed on the mounting surface. Indicia are provided on both the auxiliary support surface and the support surface to aid in placing the support jack in the similar position on the latter surface.

Abstract: Aqueous alkali metal silicate bonding compositions having a molar ratio of SiO.sub.2 :Me.sub.2 O of 2.4:1 to 3.4:1, wherein Me is sodium and/or potassium, a solids content of about 35 to 50 percent by weight, and containing triethanolamine. The bonding compositions can be mixed with fillers such as quartz sand and used for the manufacture of molded forms for the casting of metals.

Abstract: A binder containing a phenolic resin; a polyisocyanate; a curing component, and a phosphorus halide and use thereof.

Abstract: Disclosed is a vapor generator for generating a supply of a gas bearing vapors of a compound at a desired concentration. Also disclosed is a method for generating a supply of gas bearing vapors of said compound which process utilizes the vapor generator disclosed herein. The supply of gas bearing vapors can be generated on demand at a desired constant delivery pressure. The generator comprises a gas line for conveying pressurized gas from a source thereof through first pressure regulating means to a vessel; said vessel for retaining a reservoir of said compound in its liquid phase and having headspace thereabove, said vessel being insulated and having heating means to maintain said liquid and said headspace at a desired temperature. The gas line extends into the vessel to a position within the reservoir of liquid and there is terminated with gas distributor means.

Abstract: A binder is formed by polymerizing or hardening a binding material or composition, an unsaturated polymer or unsaturated monomer or mixtures thereof (polymer solution), wherein at least part of the unsaturation is ethylenic, preferably of vinyl or acrylic type, by free radical polymerization. The free radical polymerization is caused by contacting the unsaturated binding material with a free radical initiator comprising a peroxide and catalytic agent. In the preferred embodiment the binding material is a solution of an ethylenically unsaturated polymer in a solvent of unsaturated monomeric compound or compounds, in which vinyl or acrylic unsaturation is present. The binder is formed upon polymerization which occurs when the unsaturated monomer, polymer or polymer solution is exposed to the free radical initiator. Subjection of the unsaturated monomer, polymer or polymer solution to the initiator begins the formation of free radicals and subsequently the binding composition is polymerized to form the binder.

Abstract: A binder for a foundry mould or core comprises an alkali metal salt of a polyvalent organic acid or a polymerized monovalent organic acid, for example sodium polyacrylate, and an alkaline earth hydroxide such as calcium hydroxide, together with a suitable solvent. Up to 80% of the calcium hydroxide may be replaced by a polyvalent metal oxide or hydroxide. The mixture may include small proportions of other materials, such as aluminum sulphate. It is important that the pH of the organic acid salt solution before mixing with the alkaline earth hydroxide should not be too high and it should preferably be between 5 and 8, in particular between 5.7 and 6.6.

Abstract: An account is given of a method and apparatus for hardening mold parts, such as mold outer parts or mold cores for making metal castings, by using compressed air for forcing catalyst through the sand of the mold parts for reaction with a binding agent mixed with the sand.

Abstract: A process for making sintered metal articles of high strength in which a flowable mass of metallic particles is initially formed into a green compact having shape stability in a forming machine of the type used in the fabrication of sand cores in the metal casting field. The green compact is then subjected to sintering and the sintered body may be pressed, forged or mechanically shaped in other ways. The core blowing or core-sand slinging machine used to produce the green metal compact is surprisingly effective in producing a dense, reproducible structure in light of the fact that sand cores for casting purposes are intentionally made frangible to enable them to be removed effectively from the casting.

Abstract: A method of making a mold having the steps of supplying a molding sand containing a gas-hardenable binder into a space defined by a patter plate and a molding flask, covering the upper surface of the molding sand in a gas-tight manner with a film sheet, bringing the space in the molding flask into communication with a vacuum source to reduce the pressure in the space thereby to squeeze the molding sand by means of the film sheet, closing, after removing the film sheet, the upper opening of the molding flask, and connecting a hardening gas source to the space in the molding flask while reducing the pressure in the space to induce a hardening gas into the molding flask to make the gas penetrate the molding sand, thereby to harden the molding sand.

Abstract: A hydrogen peroxide system or composition for use in resin polymerization comprises a mixture of a major part of concentrated (70%) hydrogen peroxide admixed with minor amounts of phosphoric acid, a halo-substituted acid, such as hydrochloric acid, fluoboric acid or hydrofluoric acid, and sodium perborate. The peroxide composition is characterized by its storage stability, resistance to detonation, zero flammability, ease of handling and improved catalytic properties in the polymerization of certain resins. This hydrogen peroxide composition is compatible for use with a variety of organic peroxides which have been used for resin condensation polymerization and may be used in conjunction therewith. This hydrogen peroxide composition may be safely mixed with resins and resin prepolymers on the sand prior to use.

Abstract: A foundry composition adaptable to forming cores and molds comprising a foundry aggregate, a binder therefor, a catalyst and an amine, the binder being a substituted phenol.

Abstract: In a method for producing a mold for metal casting capable of being easily disintegrated by water which comprises the steps of kneading alumina sand with hydrous sodium aluminate as a binder, forming the kneaded mixture into the desired mold shape and then passing carbon dioxide gas through the mold to decompose sodium aluminate and harden it; the improvement wherein the kneading of alumina sand with the binder before mold formation is carried out in an atmosphere of carbon dioxide gas to decompose 50 to 80% of the sodium aluminate in advance.

Abstract: A peroxide system or composition for use in resin polymerization consists of 1,4-diisopropylbenzene monohydroperoxide dissolved in an organic solvent which is a solvent for hydrogen peroxide and 1,4-diisopropylbenzene dihydroperoxide. The peroxide composition is characterized by its storage stability, resistance to detonation, low flammability, ease of handling and improved catalytic properties in the polymerization of certain resins. The preferred peroxide, based on economic considerations, is a crude diisopropylbenzene hydroperoxide mixture comprising a major amount of 1,4-diisopropylbenzene monohydroperoxide and a minor amount of 1,4-diisopropylbenzene dihydroperoxide, together with solvents and unreacted materials obtained as a byproduct in the commercial manufacture of p-diisopropylbenzene dihydroperoxide.

Abstract: A binder composition for making molded products in conjunction with an aggregate includes in admixture a resin component comprising an organic solvent solution of a non-aqueous phenolic resin, a hardener component comprising a liquid polyisocyanate containing at least two isocyanate groups, the resin component and hardener component being curable by a curing agent, and an additional component comprising an oil-soluble phenolic resin dissolved in a drying oil and partially cross-linked therewith.

Abstract: Foundry mold and core compositions containing sand, an alkali metal silicate and a hardening agent therefor include, and are characterized by, a demolding agent comprising a finely divided inorganic metal compound, together with from 1 to 99% by weight thereof, of a hydrated alumina having an average grain size ranging from 0.2 to 5.mu..

Abstract: A novel process for preparing foundry cores or molds and binder materials used therefor are provided. The binder materials comprise (a) an alcohol-soluble phenolic resin, (b) a polyvalent metal hydroxide and/or oxide, (c) water, (d) an organic solvent, and (e) an alkali metal hydroxide. They are admixed with refractory particles, such as sand, and cured with carbon dioxide to form shaped foundry cores or molds. The process and materials of the invention bring about such advantages that curing may be performed with safe carbon dioxide, that shaped foundry cores or molds may be taken out from pattern immediately after curing, and that the products have a superior collapsibility after pouring a molten metal.

Abstract: A method and apparatus is disclosed for the high-speed production of foundry cores of the type in which a foundry aggregate is mixed with a curable binder, preferably an isocyanate or phenolic material, to form a core mixture which is carried within a hermetically sealed core box and is hardened by the introduction into the core box of a gaseous curing agent, preferably an amine. A positive displacement pump pumps a predetermined amount of liquid amine from a holding tank to a vaporizer where it is heated and completely vaporized. The vaporized curing agent is forced from the vaporizer by the introduction of an inert gas, preferably nitrogen, and the mixture of the inert gas and the vaporized curing agent is entrained in a low pressure air stream which carries it to the core box, thereby curing the core. After the core is cured, valves close to stop the flow of the low pressure air stream, the mixture of inert gas and curing agent to the low pressure air stream, and the flow of inert gas to the vaporizer.

Abstract: An account is given of a method and apparatus for hardening mold parts, such as mold outer parts or mold cores for making metal castings, by using compressed air for forcing catalyst through the sand of the mold parts for reaction with a binding agent mixed with the sand.

Abstract: This invention is directed to binder compositions based upon aqueous solutions of alkali metal silicates. More particularly, this invention is directed to binder compositions consisting essentially of (a) aqueous alkali metal silicate solutions having a molar ratio of SiO.sub.2 :Me.sub.2 O of from about 2.0:1 to 3.4:1, with Me signifying an alkali metal, and a solids content of from about 35 to 50 percent by weight, based on the weight of the total alkali metal solution, and (b) from about 0.1 to 10 percent by weight, based upon the weight of the total binder composition, of at least one reductively aminated mono-, di-, or oligosaccharide, and the use of such binder compositions in the preparation of molds or cores for metal casting.

Abstract: A low vacuum is applied to selected surface areas of a resin bonded sand mold to draw ambient air into selected portions of the mold. The air entering the mold burns out a significant portion of the resin binder to form a low BTU gas fuel and to recover casting heat for use in a waste heat boiler or other heat abstractions device. Therefore, foundry air pollution is reduced, the burned out portion of the molding sand is recovered for immediate reuse, and a savings in fuel and energy.

Abstract: A heat-coalescible graphitic aggregate for making graphite molds, graphite uel elements or moderating elements for nuclear reactors, and so on, is made by first forming a suspension of carbon particles in an alkaline solution of phenolformaldehyde. The suspension is then mixed together with acidulated water, the latter being heated to 40.degree. to 70.degree. C. to accelerate the reaction, with violent mixing, as in a jet device, causing a skin of insoluble phenolformaldehyde to be applied as a coating to each of the particles in suspension, which particles readily settle out and are soon separated by decanting and filtration, after which the composite solid is dried and the aqueous liquid is neutralized before being discarded.

Abstract: A pattern holder 12 and a sand tank 14 are rotatably mounted on a frame 16 so that the pattern holder can be inverted over and sealably mounted atop the sand tank. A vented pattern 26 is secured to the pattern holder and forms a first chamber between one side of the pattern and the interior of the pattern holder. A second chamber 90 is formed between the other side of the pattern and the interior of the sand tank when the pattern holder adjoins the sand tank. O-ring seals 32 and 80 isolate the chambers from the atmosphere so that a partial vacuum can be formed therein. A mixture 84 of sand and a gas-curable binder is provided in the sand tank so that the mixture will fall onto the pattern upon inverting the sand tank over the pattern holder. A flexible line 42 is provided for controllably introducing a gas catalyst into the chamber 38 in order to cure a portion of the sand-binder mixture to form a shell mold 94 of a predetermined thickness on a pattern face 36 of the pattern.

Abstract: An assembly and method of operation of forming hollow foundry products such as shell molds from a granular material utilizing a substantially automated structure including a mold box assembly having at least two box sections pivotally mounted and supported on a frame wherein each box section has a gas permeable pattern with a preconfigured working surface mounted therein. Each box section is oriented to pivot about a vertically oriented separating plane into and out of sealing engagement with one another so as to expose the interior of the mold box assembly to a catalyst gas, under pressure and in direct communication through the pattern sections with the binder coated sand or granular material in a manner which will cause formation of a core or mold of a predetermined thickness which, during its formation, is disposed directly contiguous the working surface of the pattern section.

Abstract: Disclosed is an apparatus and a method for heatless production of hollow items, such as foundry shell cores, from the mixture of granular mineral and synthetic binder, as provided by the principal process described in the patent application Ser. No. 22,170, now U.S. Pat. No. 4,232,726 issued Nov. 11, 1980.Two permeable-to-gas patterns form an inner cavity of desirable configuration and are enclosed by non-permeable halves of the pattern box, forming an outer cavity or flow space. The pattern box is mounted on two plates of the rotatable cage assembly, selectively positionable in at least three positions: charge, discharge, and transfer. Above the pattern box are pivotally mounted material supply means, sealing means, and a trimmer. Below the pattern box is a receiver of an air-less conveyor for recirculation of the discharged unhardened material. The pattern box is connected to two manifolds: one for consecutive supply of catalyst gas and the compressed air, another for exhaust and venting.

Abstract: A mold with an increased compression strength and a good collapsibility is prepared with a good efficiency by mixing refractory particles with a binder material comprising a caustic alkali-neutralized product of a copolymer containing a carboxyl group and calcium hydroxide, thereby preparing molding materials, filling the molding materials around a pattern, and blowing CO.sub.2 gas into the mold sand, thereby hardening the molding materials. Polyvinyl alcohol, calcium oxide, at least one hydroxide of zinc, aluminum, barium, magnesium, and iron, SBR latex, etc. can be added to the binder material, when desired.

Abstract: A binder containing a phenolic resin; a polyisocyanate; a curing component, and a drying oil; and use thereof.

Abstract: A process for cold forming of a shell core foundry product comprising the introduction of a first supply of binder coated granular material, hardening this first supply into the shape of separated and movably disposed core portions and subsequently introducing a second supply of binder coated granular material into spaced apart sections of the core portions and subsequently hardening this second supply in a manner which will cause fusion between the already formed core portions and the newly introduced supply of granular material in a manner which will join the previously formed core portion and thereby define an integral one piece shell core with a substantially continuous outer surface eliminating the existence of an investment hole in the formed shell core.

Abstract: A process for producing hollow items, for instance foundry cores by reacting a catalyst gas with binder coated on mineral granular material includes providing a core box having a pattern formed of microporous material and investing binder-coated granular material into a volume defined by the pattern. The core box is then sealed so that the volume encloses a gas, for instance air at atmospheric pressure, within the granular material. A catalyst gas is applied at a predetermined pressure through the pattern so that the catalyst gas exerts a uniform pressure from the interior surface of the pattern against the enclosed air volume. The catalyst gas will penetrate a distance through the granular material for curing same determined by an equilibrium condition being reached between the applied catalyst gas pressure and air pressure which results from contraction of the volume.

Abstract: A ceramic molding composition comprising an alcoholate of aluminum or a metal of the fourth sub-group of the Periodic System, a refractory metal oxide and a polyvalent alcohol, an improvement in the formation of a ceramic product wherein a ceramic molding composition is shaped and hardened, which improvement resides in employing the above defined ceramic molding composition.

Abstract: An automatic method for producing molds using chemically bonded sands which consists of a molding machine adapted to produce either honeycomb (horizontally parted) or controlled contour (vertically parted) mold elements. The molding machine is provided with a venturi-type blow head having dual blow valves and an integral air chamber. Carriage means are provided to selectively move a sand magazine and catalyst manifold between their respective fill and work stations on the molding machine. A hydraulically actuated mold receiver, trunnion rollover and shuttle car means are provided to selectively receive the completed molds from the molding machine and transport them to associated mold finishing and closing means. A hydraulically actuated pattern clamp table is provided with an enclosed pattern and stripper pin stool having a separate hydraulically actuated stripper pin plate. The enclosed pattern and stripper pin stool is an integral catalyst exhaust manifold.

Abstract: Disclosed are foundry binder compositions comprising boronated aluminum phosphate and water, cured by contacting them with gaseous ammonia or an amine. Optionally, the composition may also include alkaline earth metals and oxides, and solid polyhydric alcohols or solid organic carboxylic acids.

Abstract: Multi-core box apparatus for producing hollow foundry cores made from sand mixed with a binder that is curable either by gaseous catalytic action or by elevated temperature comprises a plurality of core boxes mounted on a housing that is rotatable in a vertical plane. The core boxes are presented sequentially by an index mechanism at various positions where treatment of material in the core boxes is carried out and at a last position a finished hollow foundry core is removed automatically from a core box.The automatic apparatus for removing the finished core from the core box, and for depositing the finished core on a conveyor comprises an elongated rod that can be inserted into the hollow core and that supports the core when the core box half portions separate. The elongated rod is carried by a spindle on a movable carriage so that the spindle and rod rotate and reciprocate thereby removing the hollow core for further treatment.

Abstract: An apparatus for making foundry cores. A pair of support plates, each of which carries a core box half, are mounted on carriages and the carriages are movable toward and away from each other to bring the core box halves into mating relation. Mounted above the support plates is a reciprocating carriage that carries a sand head and a gas head. The carriage is initially positioned to locate the sand head beneath a hopper where the head is filled with sand impregnated with an uncured resin binder, and the carriage is then shifted to position the sand head over the core box and the sand is blown into the core box. The carriage is then returned to its original position so that the gas head is positioned over the core box, and a gas, which serves as a catalyst for the resin binder, is introduced into the core box to cure the resin. A manifold system is incorporated in the support plates so that the gas discharged from the core box is passed through a scrubber before being discharged to the atmosphere.

Abstract: A machine for making a sand part for a metal casting wherein at least three frames, each equipped with means for shaping a sand part, are positioned at spaced apart points on an orbit, and indexed through three stations in the orbit wherein the shaping means are charged, gassed and unloaded.

Abstract: Sand molds or cores are prepared by coating sand particles with an acid-curing condensation type resin consisting of poly furfuryl alcohol or admixtures of poly furfuryl alcohol with other acid-curing resins. The resin composition is formed into a desired shape and is cured at ambient temperature over a period of between a few seconds and a few minutes by means of an acid produced by in situ oxidation of sulfur dioxide. Sulfur dioxide is introduced into the molding composition together with an oxidizing agent which effects oxidation of the sulfur dioxide within the mold or core composition. Preferably, the oxidizing agent is an organic peroxide incorporated on the sand or introduced with the resin composition.

Abstract: A ceramic molding composition comprising an alcoholate of aluminum or a metal of the fourth sub-group of the Periodic System, a refractory metal oxide and an agent selected from the group consisting of diketones of the formula ##STR1## wherein R.sub.1 and R.sub.2 are each independently an aliphatic radical of between C.sub.1 and C.sub.18 carbon atoms or an aromatic radical from C.sub.6 to C.sub.18 carbon atoms, a hydroxycarboxylic acid compound of the formula ##STR2## wherein R.sub.3 is an aliphatic radical of C.sub.1 and C.sub.18 or an aromatic radical from C.sub.6 to C.sub.18, and R.sub.4 is hydrogen or an alkyl radical of C.sub.1 to C.sub.4, and a polyvalent alcohol, an improvement in the formation of a ceramic product wherein a ceramic molding composition is shaped and hardened, which improvement resides in employing the above defined ceramic molding composition.

Abstract: It is known to harden foundry cores by admixing a polymerizable material therewith and then curing by addition of a catalyst. Means are provided for injecting gaseous catalysts and compressed air, sequentially, into the die which contains the admixture of polymerizable material and foundry core material. In accordance with the invention, the gaseous catalyst and compressed air respectively, are injected into the die containing the mixture of foundry material in measured desired amounts and very rapidly.

Abstract: To compact a sand-binder mixture in a mould or core box and subsequently apply a hardening gas to the mixture, I apply to the open top of the box a fluid-pervious diaphragm backed by an impervious diaphragm, apply suction to the bottom of the box to draw the diaphragm against the top of the mixture and compact the mixture, and subsequently introduce the hardening gas between the diaphragms so that it passes through the first diaphragm and permeates the mixture within the box.

Abstract: Disclosed are foundry binder compositions comprising boronated aluminum phosphate and water, cured by contacting them with gaseous ammonia or an amine. Optionally the composition may also include alkaline earth metals and oxides, and solid polyhydric alcohols or solid organic carboxylic acids.

Abstract: Method and apparatus for mixing foundry mold catalyst and carrier gas when the catalyst is in the liquid phase and the carrier is in the gaseous phase at standard conditions of temperature and pressure. The catalyst liquid is heated to vaporize it and the resulting catalyst gas is then mixed with the carrier gas under control of an automatic gas flow regulator which maintains the mass ratio between the catalyst gas and the carrier gas at the desired level in the gaseous mixture notwithstanding variations in the flow rate of either or both gases. The gaseous mixture is then blown through foundry molds and cores to cure the resin binder therein.

Abstract: A process for generating in a pressure vessel a ready supply of a vapor of a normally liquid active substance in an inert carrier gas under pressure and dispensing vapor intermittently from the supply. Once a body of the active liquid substance and overlying atmosphere of vapor is established in the vessel, the vapor is dispensed intermittently in a series of predetermined doses. Simultaneously with the dispensing of each dose, carrier gas is bubbled under pressure into a bottom zone of the vessel in minute bubbles so as to provide saturated vapor, replacing the dose dispensed. A number of conditions are coordinated to insure that saturated vapor is always dispensed. These conditions include the relationship between the depth of the vapor space, the head of liquid above the bubbling zone, the relative amount of each dose, and the initial size of the bubbles. The process is specially useful for gassing cold box cores.

Abstract: A shaped mass of particulate material such as foundry sand, admixed with a polymerizable binder, is instantly completely hardened by contact of gas catalyst therewith. The preferred method and apparatus in accordance with the present invention involves first inducing a vacuum within the shaping space of the shaping element and includes employing means for catalyst gassing of the space within the shaping element rather than of the space within the chamber in which the shaping element resides. In addition, a relatively small "aftervoid" chamber is provided and is connected to the shaping cavity at some location therein which is approximately opposite the location of the gas catalyst inlet. The latter eliminates uncured pockets which tended to result from prior methods and apparatus.

Abstract: The method is a "cold box" method in which a porous or thoroughly vented pattern is used. The pattern is preferably completely filled with sand, packed tightly, and then gassed through the pattern with a binder-curing gas catalyst. Control of depth of penetration of the gas catalyst is achieved by control of pre- and post-gassing pressures. The residual pre-gassing interstitial inert gas (usually air) is utilized as an internal cushion which limits penetration of the advancing catalyst gas.

Abstract: Disclosed is a rotary-type continuous motion core making machine capable of carrying a number of core mold boxes, each supported on a carrier adapted to move up and down, a sand distributing system adapted to inject a foundry sand mix into each of the core boxes, and a manifold system for distributing curing and purging gases to the core boxes. The machine is capable of completing a core/mold production cycle in a single circle of turret revolution. The vertical movement of the core box carrier, horizontal radial movement of portions of the gas manifold system, and movements of other parts of the machine are generated by the turret rotation and are controlled by a number of stationary contoured cam tracks. Disclosed also is a novel catalyst gas generating system, a core box assembly containing ejector pins in the top portion thereof, and a system for collecting and assembling components into a unified core and mold assembly.

Abstract: A machine is disclosed for producing rigid sand cores from a molding mixture of a refractory granular material such as sand and a hardenable binder. These rigid sand cores then are used in foundries for metal casting. The machine of the present invention is capable of producing several different types of rigid sand cores including hollow shell sand cores, hot box cores and cold box cores. The machine includes means for curing the molding mixture used to produce shell sand cores and hot box cores by applying heat to the molding mixture after it is placed in a core or molding box. Other means are provided in the machine for curing cold box cores by applying a gas catalyst to the molding mixture after it is placed in the core box. The machine of the present invention is automatically controlled by a circuit arrangement which can be programmed by the machine operator.

Abstract: A "cold box" process is disclosed in which a "green strength" sand binder mass is removed from a pattern, and placed under a canopy for gassing. The binder-curing gas catalyst is then introduced into the void space between the sand mass and the canopy until it penetrates the exposed surfaces of the sand-binder mass effecting a cure. Control of depth of penetration of the gas catalyst, and therefore, control of the thickness of the shell cured, is achieved by control of pre- and post-gassing pressures. The residual pre-gassing interstitial inert gas (usually air) is utilized as the internal "cushion" which limits the penetration of the advancing catalyst gas.

Abstract: The breakdown properties of silicate bonded foundry sand moulds and cores can be improved by including with the silicate binder a starch hydrolysate having a dextrose equivalent of less than 5.

Abstract: A refractory shape is molded on a pattern by pouring over the pattern a mixture of two slurries each of which is stable but which together react to gell. The mixture is formed by merging two slurry streams immediately above the pattern.