Abstract: An inflatable core for use in forming a thermal break in a metal frame for a door and/or window by moulding and curing thermal barrier material, such as resin, in two parallel, laterally spaced, elongate gaps defined between respective pairs of confronting elongate surfaces of the inner and outer frame elements which when assembled form a box-section member. The gaps are converted into respective mould cavities for the resin by the pressure of shoes against the elements adjacent the respective gaps to close one side thereof, the shoes being removed only after the resin has cured to leave the finished thermal break. The shoes are carried on opposite walls of a laterally expansible tube which is inserted into the box-section and is expanded to press "non-stick" surfaces of the shoes against the respective gaps ready for the moulding and curing of resin therein, while maintaining the gap dimensions.

Abstract: The invention provides for a process for constructing manhole assemblies in an excavation or elsewhere, by the utilization of an outer form, a preformed manhole barrel which is positioned and propped within the outer form pipe stub inserted partially into the inside of the preformed manhole and resting under notches cut into the preformed manhole barrel, inflatable or rigid forms (or both) are used to form simple or complex channels in the concrete which is to be poured. The form ends are adapted to fit into the pipe stub ends or may abut other forms, where complex channels are desired. The forms are carefully positioned to allow for the proper height and grade of the channel in the completed manhole assembly. Concrete is poured and when it is set, the forms are deflated where applicable and removed to be reused.

Abstract: A polymer-impregnated concrete product is obtained by placing a concrete mix in a frame capable of withstanding high temperature and high pressure in such a manner as to form therein a hollow portion, molding the concrete mix to obtain a concrete article containing a hollow portion therein, causing the concrete article as held in a tightly closed state in the frame to be cured by application of heat, subjecting the concrete article, as retained in the frame, to treatments for drying and deaeration, then supplying a monomer preparation to the hollow portion of the concrete article, applying pressure to bear upon the concrete article thereby causing the monomer preparation to be diffused into the fine voids in the concrete article, and heating the concrete article in situ thereby allowing the diffused monomer to be polymerized.

Abstract: The present invention relates to low-expansion ceramics having a chemical composition of the ceramics essentially consisting of 2 to 20% by weight of magnesia (MgO), 10 to 68% by weight of alumina (Al.sub.2 O.sub.3), and 30 to 80% by weight of titanium in terms of titanium oxide (TiO.sub.2), wherein the major component of crystalline phase thereof is magnesium-alumium-titanate phase, and the ceramics have a coefficient of thermal expansion of not more than 20.times.10.sup.-7 (1/.degree.C.) in a temperature range of 25.degree. C. to 800.degree. C. and a melting point of not lower than 1,500.degree. C., wherein the magnesium-alumium-titanate phase as the major component of the crystalline phase thereof is given by a chemical formula Mg.sub.10x Al.sub.8y Ti.sub.5(1-x-y) O.sub.(10+2y), here 0.02.ltoreq.x.ltoreq.0.20, 0.10.ltoreq.y.ltoreq.0.68, and 0.20.ltoreq.(x+y).ltoreq.0.

Abstract: A method for constructing a building utilizes flexible bags. An outer bag is inflated, and structural material poured through the bag's inlet to define the floor. An inner bag, smaller than the outer bag, is inflated inside the outer bag. Structural material is poured into the space between the inner and outer bags, which are preferably supported by water and air pressure. This defines the walls and roof of the building. Once the structural material has set, the inner bag may be removed and used for further construction.

Abstract: A solar water tank for use in solar heating systems includes an insulated tank with flow systems comprised of a plurality of inlet and outlet tubes, heat exchangers, level switch and supplemental heating element, all assembled together with the manway cover for the tank in a unitary embodiment. The tank also includes a layer of polyurethane foam insulation on its interior surface. Forming apparatus for placing the insulation layer in the tank includes a flexible synthetic membrane in the form of an enclosed bag adapted for positioning in the interior of the tank.

Abstract: In the isostatic molding of linings, an improved flange-to-flange seal is obtained when a generally rectangular ring is employed in a generally rectangular groove.

Abstract: A process and arrangement for introducing a material such as a foam into automobile body cavities for at least one of noise insulation or increased rigidity. The cavities may be provided with open spaces or be adapted to only be partially filled with the foam. A bag is initially introduced into the cavity with the bag being provided with a filler opening. The volume capacity of the bag corresponds approximately to the volume of the automobile body cavity or a portion of the body cavity which is to be filled with the foam. A mixture of expandable components is introduced into the bag and, following an expansion reaction or a setting, the foam fully fills the bag.

Abstract: A method and apparatus for thermally isostatically densifying a sample, including placing the sample to be densified into a pressure vessel filled with a thermally expansive pressurizing medium with the medium intermediate the vessel and sample; and varying the thermal energy of the medium to cause it to expand and exert increased pressure to densify the sample.

Abstract: An expandable member is disclosed that includes a molded body of elastomeric material with a core embedded therein. At least a portion of the core is not bonded to the body. A fluid conduit is provided through which fluid can be injected between the core and the unattached portion of the body to move the core and the unattached portion apart and expand the member.

Abstract: The invention pertains to the manufacture of articles of thermosetting plastics and other materials. In a first stage, a solid article is formed from a particulate material by introducing such material into a first chamber defined partially by the backing surface of a backing member and partially by the opposed pressing surface of a pressing member. The backing member is frangible and is removably mounted on a support. The first chamber is then closed and the pressing member advanced toward the backing surface to contract the first chamber and compress the particulate material between the pressing and backing surfaces to form the solid article. The pressing member is then retracted, the first chamber is opened, and the backing member and solid article are removed from the support as a unit. Finally, the backing member is fractured and the fragments are removed from the solid article. In a second stage, the convoluted article, or any other similar body is supported in a chamber structure.

Abstract: An improved ring molding apparatus for molding toothed V-belts is provided which comprises, in one embodiment, a ring mold having an outer circumferential surface which is grooved to provide a mating surface for a bladder having an inner surface having a plurality of tooth-forming projections and recesses. According to another embodiment, the bladder has a plurality of axially-running projections and recesses arranged in an annulus for each of the mold cavities. Also provided is a method for making molded V-belts which comprises curing the belt in the above molds.

Abstract: A method of manufacturing a ball for use in volleyball or soccer includes the steps of manufacturing a spherical hollow body of a brittle material, sticking cloth strips in an overlapping manner on the spherical hollow body to provide a bag body, cutting a predetermined portion of the bag body to make an opening thereon, collapsing the spherical hollow body in the bag body into pieces, taking the collapsed pieces out of the bag body through the opening, putting a tube having a valve through the opening into the bag body, sticking rubber ribbons on places corresponding to the overlapping portions of the cloth strips, and sticking leather sheets on the rubber ribboned bag body to provide an outer layer for the ball.

Abstract: Apparatus for the preparation of hollow plastic articles wherein a more rapid operating cycle is obtained with less effect upon the temperature of the parison. The apparatus includes a first core, means for providing a parison thereon, a temperature controlled first mold engageable with said first core and parison, means for separating the first core from the first mold and parison contained therein, a second core in spaced relationship to the first core, means for transferring the parison to the second core, a blow mold in spaced relationship to said first mold for fully expanding the parison and means for transferring the second core and parison to the blow mold, wherein the blow mold is stationary and the second core with parison thereon is brought into alignment with the blow mold and is inserted therein.

Abstract: A hollow tank is formed by placing a hollow glass fiber reinforced inner container within a hollow rigid form comprising pieces assembled around the inner container and spaced from it to leave an air gap between the inner container and the inner wall of the assembled form. A suitable concrete material is introduced into the space between the inner container and the assembled form and is allowed to cure as a jacket of concrete integrally attached to and enclosing the inner container. The inner container may be formed by coating an inflated balloon with a thin layer of polyester resin and thereafter spraying on the glass fiber reinforced material to a thickness of a few mm. The concrete may be a standard flowable concrete or a polyester concrete, which is a resin-bonded gravel mixture. The concrete may be the outer layer formed as a jacket around the glass fiber reinforced inner container, or another glass fiber reinforced layer may be formed on the outer surface of the concrete.

Abstract: A method and apparatus for forming molded ice sculptures includes a selection of molds fabricated of form retaining, flexible, resilient plastic material. Each mold includes holes in the base thereof through which supporting wires are placed. The mold is inverted, base up, within a box slightly larger than the mold, with the wires impinging on the box and supporting the mold. The mold is filled with water and frozen. Thereafter the mold is removed from the box, the wires removed from the mold and the mold stripped from the frozen sculpture.

Abstract: A novel method is disclosed for the manufacture of a hollow graphite-epoxy structural part with high composite density and using tooling that eliminates the necessity of autoclave and similar high external pressure curing equipment. The method of manufacture in part involves the use of a rigid hollow frangible mandrel and superimposed flexible pressure bag element which subsequently develops high internal pressures in the part being processed during composite curing stages.

Abstract: Method of making a casing reinforced by a stretchable glass fiber preform is disclosed. The casing may be reinforced by metal or a glass fiber mat which is shaped to provide positive engagement with the stretchable fiber preform before its impregnation by a matrix-forming resin.

Abstract: A tennis racket frame is constructed primarily of an elongated hollow tube member having a wall thereof consisting essentially of a plurality of concentric layers of high tensile strength fibers impregnated and bonded together by binder resin, at least two of the layers being helical windings of opposite unidirectional hands, and the head portion of a racket frame having a groove molded therein to receive the loop portions of the strings in recessed relation to the surrounding surface areas of the frame. The frames are made by a method including the use of a special mandrel on which the layers of fiber are wound under controlled conditions providing extra material in the head portion which is formed into the wall of the grooved portion of the head without affecting the overall sectional dimensions of the frame.

Abstract: Method of and apparatus for fabricating spiral wrapped cartridge cases or the like, in which an expandable bladder positioned within the interior of the cartridge case is initially expanded by application of hydraulic fluid at relatively low hydraulic pressure levels and at relatively high flow rates until the bladder substantially fills the cartridge case and then is pressurized at relatively high hydraulic pressure levels to form the cartridge case within a die cavity. Hydraulic pressure is applied to the bladder by a hydraulic pressure generator which is powered solely by the closure of the platens of a conventional industrial press between which the die and the pressure generator are mounted. The pressure generator shifts automatically from its low pressure to its high pressure mode of operation as the press platens close.

Abstract: Method and apparatus for reversing and flattening a driver's restraint cushion composed of a pair of overlapping sheets. The apparatus includes a loading platform having an aperture therein of a size generally corresponding to the size of a circular opening centrally formed in one of the sheets of the restraint cushion. A retainer ring surrounds the aperture and extends into the circular opening of the restraint cushion when the latter is positioned on the loading platform. Subsequently, a vertically movable ram engages and forces the other of the sheets of the restraint cushion through the aperture so as to cause the inside and outside surfaces of the two sheets to reverse after which pressurized air flows through the ram to inflate the cushion and a flat plate presses the inflated cushion into a pancake form.

Abstract: A method of making hollow aircraft rotor blades from laminated material. An xpandable mandrel is first made from curable materials and then a composite build-up of epoxy material is made by layering a plurality of prepreg plies of curable material over the expandable mandrel. The mandrel and build-up of epoxy materials are then placed in a mold and pressure is applied to expand the mandrel which, in turn, expands the build-up of material against the mold. The mandrel and composite build-up of material are then cured and the mandrel becomes an integral part of the rotor blade.

Abstract: A device is disclosed for forming blanks from pulverulent porcelain mater which blanks have a foot piece and sloping sides. The device has an upper mould which acts against a lower mould, the upper face of which lower mould is formed by a distendable, elastic membrane closing the upper end of a liquid filled chamber. Within the chamber, a central member provides resilient support for the center of the membrane. The parts are so arranged that upon closing of the mould portions a layer of pulverulent porcelain composition is gradually shaped and compressed between the upper mould and the membrane into a concave article blank including a foot piece, and where necessary a relief design, which blank is of uniform thickness and density.

Abstract: A building structure and method of making the same are disclosed wherein an inflatable form is inflated and an insulation layer of urethane form is applied to the undersurface of the foam. Hanger members are secured to the foam layer by adhesively affixing planar base portions of the hangers to the foam layer whereafter additional foam is applied to embed the hanger bases. Reinforcing mesh is secured to and supported by the hangers followed by the application of one or more layers of a cementitious material which is allowed to cure. Air pressure beneath the form is progressively increased to maintain a substantially constant uplift force on the foam. The inflatable form may be removed after curing and a protective coating applied to the outer exposed surface of urethane foam to protect it from ultraviolet degradation.

Abstract: A method of joining pipes in which a sleeve is placed over the adjacent ends of the pipes so as to overlap each pipe. The sleeve fits with clearance around the pipe ends. The ends of the clearance space are closed by inflating hollow sealing rings and then epoxy resin is injected into the clearance space to fill the space. The pressure of the epoxy resin composition is then raised to a pressure substantially greater than atmospheric and the pressure is maintained until the resin composition is set.

Abstract: An apparatus and method for molding structural parts from fiber reinforced plastic composite. The apparatus is comprised of a rigid container, one or more pads of silicone rubber housed inside the container to exert pressure on the part, and one or more expandable diaphragms housed inside the container to control the pressure exerted on the part by the pads. The method used to mold a complex-shaped part from fiber reinforced plastic composite material is to lay up the part on the pads and place the pads, together with the part, between the diaphragms which are housed in the container. The container is then closed and placed in a temperature control chamber and the diaphragms connected to an external pressure control system, after which the part is cured by increasing the temperature of the chamber to the curing temperature of the part, while at the same time controlling the pressure exerted on the part by controlling the pressure in the diaphragms.

Abstract: A one-step method of both making and tortuously shaping three component tubular articles is disclosed, the tubular articles being of the hollow skin-core type of the desired complex configuration, strong and rigid, free from porosity, light in weight, resistant to high and low temperatures, comprised of a thin and relatively fragile elongated and longitudinally edge-lapped sheet tube integrally encased in a strongly reinforced plastic shell providing both tube-forming support and tube performance protection for fluid conveying and storage applications. The tube-forming sheet can be of specialized rubbers or plastics or metallic foils. It is advantageously susceptible to inspection to the required degree before incorporation into the article and may be capable of subsequent in place modification.

Abstract: In making a hard multi-tubular structure, one starts with a flat woven or knitted hose fabric comprising a plurality of side-by-side hoses; the hoses of the fabric are caused to expand and to set in their expanded configurations, which may be circular or substantially square in cross-section by a hardenable medium with which the fabric is impregnated or coated. Optionally, a hardenable covering and/or filling is provided over or in the hoses.

Abstract: The invention relates to a method and apparatus for making hollow, resin-impregnated fibrous fabric articles. Specifically, it relates to a method wherein a reusable mandrel is made sufficiently rigid to receive a lay-up of the article to be manufactured. The rigidized assembly is placed within a female mold, derigidized and expanded to apply pressure from within, thereby forcing the lay-up against the interior of the mold. Heat is applied to cure the resin, producing an article having a very high degree of dimensional accuracy.

Abstract: Method for making tubular articles of tortuous configuration and of resin impregnated material. The method is intended to avoid resin-starved areas in the product. Specifically, tubular articles having high curvature, sharp transitions in cross section size and/or shape and close tolerance ends are provided these being made by applying and incorporating selectively placed porous components.The article is formed in a mold by an inflatable mandrel which carries a continuous, surrounding knitted fabric component and one or more localized foam, felt and/or fabric devices of porous nature which control the supply, flow and/or final disposition of resin matrix in the molding process.

Abstract: A method and a device to cast elongate concrete structural members formed internally with channel means in horizontal moulds. The channel means is formed by a double-wall inflatable hose of an elastic and flexible material which is introduced into the mould and is provided with support walls extending between the inner and outer hose walls so as to divide the space therebetween into longitudinal chambers. After inflation of these chambers, concrete is poured about the hose while at the same time weights displaceable in the interior of and in the longitudinal direction of said hose, exert a load on the hose, thus preventing it from being lifted from its predetermined position inside the mould by the concrete.

Abstract: In a fuser roll for electrostatic copying machines comprising a cylindrical metal core surrounded by a cylindrical body of elastomeric material having an outside cylindrical sleeve of protective material, the end surfaces of the elastomeric material are protected from the deleterious effects of silicone fluid by sealing rings of elastomeric material such as fluorosilicone which is resistant thereto. The rings, which are rectangular in cross section and are made of uncured, deformable material, are inserted in the ends of the sleeve with the ends of the sleeve protruding. The sleeve is assembled with the metal core and placed in a cylindrical mold. Silicone rubber is injected into the space between the core and the sleeve and the sleeve and rings are expanded into contact with the mold wall. The roll is then cured.

Abstract: A method and apparatus for making flexible rubber tubing with axially spaced annular or helical corrugations. A sleeve of uncured vulcanizable rubber is slipped over a forming mandrel and an external form comprising a length of flexible, corrugated, axially compressible rubber tubing is positioned over the sleeve. The interior wall of the external form defines a shaping surface for use in forming embryonic corrugations in the sleeve. The sleeve is radially expanded into the shaping surface and the form and sleeve are axially compressed concertina-fashion to increase the radial dimensions of bulged portions of the sleeve between the corrugations of the external form to make embryonic corrugations in the sleeve. The sleeve and external form are then removed from the forming mandrel and the sleeve is placed on a curing mandrel with the corrugations at desired spacings, after which the sleeve is cured.

Abstract: A building method of the kind wherein an inflatable former, made of a flexible, substantially inextensible material is sealingly anchored to a base and is inflated to a predetermined pressure and, while maintaining said pressure substantially constant, a cementitious material is applied to the outer surface of the former to a required thickness and, after the material has set, the former is deflated, released from the base and removed for reuse, including the steps of:(a) inflating the former to a predetermined initial inflation pressure,(b) applying successive layers of cementitious material to said former, and(c) continuously or intermittently raising said inflation pressure in correspondence with the increasing thickness of said layers.

Abstract: To permit simple manufacture and reliable attachment of the center electrode into a ceramic body, an elastic tubular press mold is located in a press body, the press mold being closed off by a movable plug having a needle-like extension with a gripping end formed thereon to receive the center electrode before the plug is inserted into the tubular mold. Ceramic material is then filled into the mold, the plug closing off one end thereof, the mold is closed with a second plug, and pressure in the order of from 250 to 400 bar applied to the outside of the elastic mold to compress the ceramic material and embed the center electrode tip therein. Upon release of pressure, the compressed ceramic, with the center electrode therein can be removed from the holding tip of the needle-like extension of the plug, for subsequent grinding to size, sintering, firing, and glazing, if desired.

Abstract: A method is disclosed of reshaping a sheet of resiliently deformable material impervious to fluid by conforming it to the cavity of a female mold and casting a flexible plastic foam into contact with said sheet material, whereby said material is integrated with the foam and forms a cover sheet therefor. A perforated elastic diaphragm is interposed, during the reshaping and foam casting process, between the cover sheet and surface of the mold cavity so that the cover sheet is in superimposed direct contact with the diaphragm throughout its area. The two are clamped to the periphery of the mold to form a seal thereat, and a differential pressure is applied across the cover sheet and diaphragm. The sheet is therefore deformed against the walls of the mold simultaneously with the diaphragm and is stretched evenly with the diaphragm in order to produce uniform thickness.

Abstract: A process for manufacturing a flexible cylindrical body includes the steps of providing a flexible preform of non-resilient synthetic material which is inflatable to cylindrical form, inserting the preform into an elongated coil of an electrically conductive material having a diameter relative to that of the preform in its inflated cylindrical form such that the preform is expanded in an unstressed condition into engagement with the inner diameter of the coil, the inner face of the coil being coated with an adhesive material, and applying a predetermined voltage to the coil to thereby fuse the adhesive material and connect the coil and preform.

Abstract: A plastic foam rigid swimming pool cover is fabricated by forming an amorphous plastic foam material into a shape conforming generally to the periphery of the pool and into a shape for covering the swimming pool. The cover is also shaped for lifting as an integral unit from a covering position to an uncovered position above the pool via the intermediary of a plurality of lifts such as electric or hydraulic jacks coupled to the pool cover at a plurality of points spaced around the periphery thereof. The amorphous plastic foam material is formed to the desired shape by either casting or spraying the material into or onto a form of proper shape. In some embodiments, the reinforcing members are embedded in the foam to provide added strength and rigidity. The foam cover may include soil and plant receptacles for landscaping. The cover may be formed in situ or at a remote location to a template and segmented for transport to the pool and reassembled in situ.

Abstract: A flexible resilient printing plate adapted for use on a magnetic printing cylinder is formed by mixing a ferrous metal powder within a volume of liquid vinyl plastisol, casting the mixture onto a face layer of at least partially cured vinyl plastisol to form a base layer, and then heating the combined layers to cure the base layer and fuse it to the face layer to form a flexible multiple layer mold sheet. The base layer is shaved to provide the mold sheet with a substantially uniform thickness, and a porous fibrous impression mat is placed in contact with the face layer. The mat and mold sheet are heated and are placed within a diaphragm press with a porous cloth between the mold sheet and the diaphragm. The mold sheet is pressed into the mat to form a printing plate which is allowed to cool during the pressing operation. The mat and plate are magnetically retained on the bed for a shaver, and the base layer of the plate is shaved to produce a precise uniform caliper.

Abstract: The production of a moulded stressed concrete pipe in which stressed coated tendons are completely embedded in the finished article. The pipe is moulded in at least one longitudinal segment joined only by helically concentrically positioned tendons. The cured segments are then expanded radially to stretch and stress the tendons, the gap formed between the segments being filled with filler material to maintain the stress in the tendons. There is also disclosed a method where the tendons are stressed on a former prior to immersion of the tendons and former in a concrete pour. The former is segmented and collapsible so that the tension in the tendons can be transferred from the former to the concrete when it has cured, thus forming a stressed pipe structure.

Abstract: A method of making disc records, particularly video discs from thermoplastic sheet material. In a press a thin flexible matrix is disposed between the sheet, which is backed by a resilient cushion, and a flexible diaphragm which constitutes a wall of a hydraulic pressure chamber.

Abstract: A method for curing vulcanizable elastomeric articles positioned between a mold surface and a pressure chamber including the steps of introducing into the chamber a hot fluid of relatively high heat capacity, e.g., steam, under pressure for a sufficient period to soften the article, introducing into the chamber a gas of relatively low heat capacity and pressurizing the gas in the chamber at a pressure substantially greater than the pressure under which the hot fluid was introduced, and thereafter vulcanizing the elastomeric article.

Abstract: A method of lining a cavity, such as, for example, the head box for an ingot mold, comprising applying to the surface to be lined a lining of a self-supporting deformable fibre mat refractory composition and then exerting pressure on that lining so as to deform and conform it to the shape of the cavity.

Abstract: An improved molding apparatus is described for use with relatively light weight molds, particularly molds for articles having a plurality of voids therein. A light weight two-piece mold, one-half being substantially rigid and the other relatively flexible, is disposed in a jig. The two halves of the mold are held in sealing relationship by inserting a hollow inflatable bag between the exterior of the relatively flexible mold piece and the interior wall of the adjacent jig member and inflating said bag to a pressure superior to that exerted by the expanding foam mix in the mold.The use of the improved apparatus obviates the need for molds of high structural strength (and hence excessive weight) and gives molded articles, particularly those of complex configuration, which are free from flashing.

Abstract: A method of lining a passageway with a hard, rigid pipe of thermosetting resin, wherein a tubular fibrous felt is immersed in the resin to form a carrier for the resin. The immersed felt and resin have an inflatable tube therein and this tube is inflated to shape the resin to the passageway surface. The resin is cured to form the hard, rigid lining pipe with the felt embedded therein.

Abstract: A method of constructing concrete shells of various design employing a plurality of inflatable water filled bladders which are aggregated to produce a mold having the configuration of the final structure. After a conventional concrete shell, which is formed by depositing concrete over the desired mold, has set, the bladders are drained, removed from the shell, and ready for reuse.

Abstract: Method of making an annular sand core portion by shaping sand and binder in an annular mold with an inflatable bladder. The bladder is inflatable and expandable to form and press sand core material between itself and the mold body while exerting uniform compressive force over the total surface area of the core material thereby forming a portion of a hollow core of precise external dimension and uniform overall strength.

Abstract: A method and a device for making objects from plastics, wherein a plastic present in the moulding cavity is made to set while pressure is maintained, said moulding pressure being made to act on the plastic being moulded by means of the inflation of one or more fully or partly flexible and expansible moulding tools.The invention relates to a method of making objects from plastics by means of compression moulding, a plastic present in the cavity of a mould being made to set while a moulding pressure is maintained, and also to a device for performing this method.Plastics can be moulded in any given manner while in the plastic condition. For example, the plastic can be introduced into a hollow mould for this purpose. While the plastic material, particularly thermoplastic material is setting, sunk spots may form on the surfaces and pockets may arise inside the plastic as a result of shrinkage, especially when the object being moulded has relatively thick walls.

Abstract: A method of and apparatus for making a self-supporting dome-like skeletal structure including the steps of preparing a substantially flat surface, assembling an array of multi-sided first members which is criss-crossed by paths comprising adjacent flanges of adjacent first members, placing a strip of pliable material along each path and interweaving the strips at intersections thereof, securing the ends of the strips, mounting over each first member a second member of configuration similar to said first member, said second members peripherally sealingly resting on the strips on the flanges of the first members, placing concrete in troughs having as sides the sides of adjacent second members and as bottoms the strips on the flanges of the first members and introducing pressurized gas below said array of first members to cause it to assume a dome-like configuration, allowing the concrete in the troughs to set and exhausting the gas from below the first members so as to strip at least said first members from the

Abstract: A disposable inner mould or form for the construction of a boat hull, such mould comprising a hollow hull-shaped form made of flexible non-stretch plastic sheet material tailored in the shape of the inner surface of the boat hull. There may also be provided means for securing such form in an inverted position on a base member, means for inflating said form to adopt its predetermined non-stretch tailored hull-shape as aforesaid, and contour control means for supporting portions of the form to retain it in its tailored hull-shape. The form may have an opening at the stern end for reception of a rigid panel therein.