Abstract: A method of manufacturing angiographic catheters comprises providing a length of elastomeric tube of a predetermined outer diameter and braiding multiple strands of wire wrapping about its exterior. A bonding agent is applied to the wire wrapping in circumferentially extending bands to bond the strands to each other. Thereafter, the wire wrapping is ground away at predetermined spaced locations along the length of the elastomeric tube to provide a series of wire wrapped sections joined by non-wrapped sections with each of the wire wrapped sections having at least the ends thereof enclosed by at least portions of the circumferentially extending bands of bonding agent. An elastomer layer is located over both the wire wrapped sections and the non-wrapped sections throughout the length thereof.

Abstract: A method for making a reinforced tubular laminate. A dry braided fiber sleeve is placed between a mandrel and spiral tape wrap either over, under, or layered with a pre-preg material. During the initial stages of the curing process, while the temperature is rising, the resin in the pre-preg material flows and wets out the dry braid. When the final cure takes place, the braid becomes an integral part of the finished laminate. The choice of fiber materials and braid angle permit various tubular laminate strengths. The selection of fiber colors and patterns permit a wide variety of tubular laminate aesthetic characteristics.

Abstract: A method of manufacturing an interior coated weeping hose comprised of warp yarn and filler yarn and having an interior coating, the warp yarn comprising a first warp yarn and a second warp yarn having a larger diameter than the first warp yarn, the first warp yarn comprising the bulk of the warp yarn in the hose, the second warp yarn being disposed axially about the circumference of the hose, comprising the steps of weaving the first warp yarn, the second warp yarn, and the filler yarn together to form a woven hose, applying a coating to the inside wall of the woven hose, pulling said woven hose over a mandrel to remove the coating on the interior surface of the second warp yarn while the remainder of the interior surface remains coated.

Abstract: Fibrous substrates for the production of carbon and/or ceramic (including mixtures of these) fiber reinforced carbon and/or ceramic (including mixtures of these) matrix composites, particularly friction discs, and to methods of manufacture of same. Offcut waste fibrous sheet material may be recycled and reformed into a web useful in the manufacture of such composites.

Abstract: A method for manufacturing a double jacketed fire hose, and a double jacketed fire hose comprising an inner jacket and an outer jacket, said inner jacket being encapsulated with polyurethane, said inner jacket residing within said outer jacket, said inner and outer jacket having a controlled net twist.

Abstract: A method of manufacturing, extruding, milling and welding a high torque, thin monolithic walled guiding catheter having resilient reinforcement material (8, 23, 29, 70, 73) integrally spiralled or braided into monolithic walls (21) of flexible material. A solid lubricant, also referred to as dry lubricant, comprised of either special fluorine containing materials or polymeric organic silicon compounds is embedded into interior and exterior wall surfaces of the catheters. Smooth interior walls (11) are channeled (10) to decrease friction resistance, to trap resistance particles and to dissipate friction heat in the high ratio of surface area to cross-sectional area of small catheters. Number of spirals or braids of reinforcement strands per unit of length, number of layers of strands of the catheters, catheter diameter and progressiveness thereof are designedly different for separate portions of particular catheters.

Abstract: Disclosed are methods for forming flexible, kink-resistant shaped fabric products which are particularly well adapted for protecting and/or covering elongate substrates, such as cables, conduits, wiring and the like. The shaped fabric products include a wall portion formed from a filamentary material which is resiliently set in a spiral configuration with respect to the longitudinal axis of the shaped product. The wall portion may also preferably formed with a filamentary material in the form of circumferential hoops substantially conforming in shape and size to the cross-sectional configuration of the shaped product.

Abstract: The invention provides improvements to a composite member that has a plurality of plies. The improved composite member has (1) an interior ply which functions to dampen or resist sudden forces exerted on the composite member, (2) an intermediate load-carrying ply, and (3) an exterior abrasion-resistant ply. These plies have multiple, often intertwined fiber components disposed or imbedded with a matrix material, preferably Nylon-6 thermoplastic, to inhibit sharp edges during breakage. One or more of the plies typically has "bi-axial" or "tri-axially" braided fiber geometries wherein one or more fibers are helically wound about the circumference of the member. The helically oriented fibers are oriented at a selectively variable angle which influences the overall bending strength of the composite material.

Abstract: An intravascular catheter introducer which comprises a tubular sheath having a distal end, for extending through the skin of a patient and into the vascular system. The sheath defines a lumen for receiving a catheter. A hub is carried on the proximal end of the sheath. The hub defines a bore communicating between the lumen and the exterior. A catheter-penetratable seal is carried in the bore, with the sheath carrying an embedded tubular reinforcing strand member along at least a majority of its length. Thus improved kink resistance is provided. Also, improved frictional characteristics are provided when the tubular sheath comprises polytetrafluoroethylene.

Abstract: A method for producing continuously a long reinforced hose having a plurality of reinforcement layers. An inner reinforcement layer is formed by braiding steel wires or fibers on a mandrel and a rubber is extruded onto the inner surface of the reinforcement layer to form an inner rubber layer therein. An adhesion rubber is then extruded onto the outer surface of the inner reinforcement layer to form an adhesion rubber layer thereon and at the same time an outermost reinforcement layer is formed on the adhesion rubber layer by braiding on a mandrel. The unvulcanized hose including the respective layers is pulled at a speed higher than the braiding speed of the outermost reinforcement layer, thereby firmly joining the reinforcement layers and then pulled at a lower speed but still higher than the braiding speed, thereby more firmly urging both the reinforcement layers to each other.

Abstract: A method and apparatus for continuously manufacturing a reinforced, flexible, porous, tubular pipe. The reinforced, flexible porous tubular pipe comprises an extruded porous inner layer, spiral wound open mesh webbing surrounding the porous inner layer, and an extruded porous outer layer. A granular elastomeric material is blended with a polyethylene polymer thermoplastic and an emulsifier, heated and passed through a first extruding means to form a flexible, tubular porous inner layer. The porous inner layer is passed through a quick cooling means, then an open mesh webbing is spirally wound about the porous inner layer. The porous inner layer and the open mesh webbing are then passed through a second extruding means to form a porous outer layer. The reinforced, flexible porous tubular pipe is then cut to length and coiled to suit manufacturing preference.

Abstract: An improved welding rod having a solid homogeneous core of thermoplastic material and a resistance element comprised of a plurality of wires is presented with a method and apparatus for forming the welding rod. The welding rod is positioned between members of the thermoplastic material to be welded and a current and pressure is applied to the resistance element causing the thermoplastic material of the solid core and the adjacent thermoplastic members to fuse and form a unitary weld. Simultaneously the electrical resistance element is embedded in the weld, mechanically reinforcing and strengthening the connection. There is also disclosed a method for electric fusion welding of thermoplastic members wherein the welding rod is pre-attached to one of the thermoplastic members.

Abstract: A method for producing continuously a long reinforced hose having a plurality of reinforcement layers. An inner reinforcement layer is formed by braiding steel wires or fibers on a mandrel and a rubber is extruded onto the inner surface of the reinforcement layer to form an inner rubber layer therein. An adhesion rubber is then extruded onto the outer surface of the inner reinforcement layer to form an adhesion rubber layer thereon and at the same time an outermost reinforcement layer is formed on the adhesion rubber layer by braiding on a mandrel. The unvulcanized hose including the respective layers is pulled at a speed higher than the braiding speed of the outermost reinforcement layer, thereby firmly joining the reinforcement layers and then pulled at a lower speed but still higher than the braiding speed, thereby more firmly urging both the reinforcement layers to each other.

Abstract: Process for the manufacture of a flexible polymeric structure comprising a sealant barrier, consisting of a multilayer film a few microns thick, oriented longitudinally, in a continuous manner, whereby all of the components of said flexible structure are intimately bonded by a final heat treatment. Flexible polymeric structures manufactured according to this process. Application to the fields of the transport of all fluids and protection against external aggressive agents.

Abstract: Process for the manufacture of a flexible tubular structure comprising a sealant barrier, consisting of a monolayer film a few microns thick, oriented longitudinally, in a continuous manner, whereby all of the components of said flexible structure are intimately bonded by a final heat treatment. Flexible tubular structures realized according to this process. Application to the fields of the transport of all fluids and protection against external aggressive agents.

Abstract: A permanent marking article for use with an elongate object, consisting of a strip of transparent polymeric film having an upper and a lower surface, at least a portion of the upper surface being imprintable, the polymeric film being fusible to itself with the passage of time, and remaining transparent even after fusion such that any marking placed on any portion of the article remains readable even if covered by one or more overwrapping portions of the strip.

Abstract: A method for manufacturing a heat-shrinkable hose, wherein at least one shrinkable thread is wound around a basic hose element. A cover hose is provided that surrounds the basic hose element and overlies the heat-shrinkable thread. Longitudinal supporting threads can be provided for additional reinforcement.

Abstract: A flexible hose construction and method of making the same are provided, the flexible hose construction comprising an inner corrugated hose made of polymeric material and having a plurality of outwardly convex projections with recesses therebetween and extending from one end thereof to the other end thereof, an outer sleeve of reinforcing material disposed in telescoping relation on the inner hose, and a tube of polymeric material disposed between the sleeve of reinforcing material and the inner hose and extending in a generally straight-line manner from projection to projection of the inner hose so as to tend to prevent the sleeve of reinforcing material from entering into the recesses of the inner hose an amount that would tend to substantially reduce the flexibility characteristics of the inner hose.

Abstract: A process for the manufacture of a thin-walled tube of fluorinated resin, particularly polytetrafluoroethylene, in which a ribbon of fluorinated resin obtained by lubricated extrusion and calendaring, is wound into a tube on a mandrel, the winding of the ribbon being performed in a plurality of layers, and the thus-wound ribbon on the mandrel being brought to a temperature above the sintering temperature of the fluorinated resin for sufficient time to produce sintering. The wound tube and the mandrel are cooled; while on the mandrel the thin-walled tube is rolled to elongate the tube, to reduce the thickness of the tube, and to increase the inside diameter of the tube; and then the mandrel within the tube is extracted.

Abstract: A method of forming a hose assembly (10) of the type adapted for carrying fuels and other corrosive fluids. An inner liner (16) of a fluorocarbon material is extruded. The inner liner (16) is then passed through a reservoir containing a dispersion including a fluorocarbon polymer material and a fluid. Glass fibers are then braided about the exterior of the inner liner (16) to form a braided layer (18) having the dispersion thereabout such that the dispersion penetrates the interstitial spaces of the braided layer (18). Subsequently, the assembly (10) is heated to remove the fluid. The assembly is then sintered to cure the fluorocarbon polymer material into a coating dispersed throughout the braided layer (18) and about the inner liner (16).

Abstract: A process for producing a hybrid flexible having a synthetic resin core tube, a middle rubber layer, a braided fiber reinforcement layer and an outer rubber layer. The process includes a preparing step where the core tube is previously formed to a tube having an inside diameter less than a finished size, and the reinforcement is braided with a braiding angle less than rest angle, and a vulcanizing step where the hose is heated under a condtion that internal pressure is held in the synthetic core.

Abstract: A flexible hose construction and method of making the same are provided, the flexible hose construction comprising an inner corrugated hose made of polymeric material and having a plurality of outwardly convex projections with recesses therebetween and extending from one end thereof to the other end thereof, an outer sleeve of reinforcing material disposed in telescoping relation on the inner hose, and a tube of polymeric material disposed between the sleeve of reinforcing material and the inner hose and extending in a generally straight-line manner from projection to projection of the inner hose so as to tend to prevent the sleeve of reinforcing material from entering into the recesses of the inner hose an amount that would tend to substantially reduce the flexibility characteristics of the inner hose.

Abstract: The invention relates to a process for manufacturing a hose including a layer of ultra-high molecular weight polyethylene on at least the inside or the outside, which layer is directly bonded to an elastomeric layer, the layer of polyethylene being provided by folding an oblong polyethylene film to form an oblong tube with an overlapping seam in its longitudinal direction, resulting in a hose fit for uses, even at low temperatures, in which the inside and/or the outside of the hose are/is exposed to the action of chemical substances and/or of substances having a strongly abrasive action.

Abstract: A method of making a lightweight hose assembly including a step of extruding the inner liner. A nonmetallic material is then braided about the exterior of the liner. The inner liner and braided layer are then passed through a reservoir containing a solution of the fluorocarbon polymer. The solvent is then removed, leaving a fluorocarbon polymer coating dispersed throughout the braided layer.

Abstract: An applicator for applying resin to fibers being braided in a tubular shape (e.g., in the manufacture of a fuse casing), the applicator having a wiping surface on which the fibers wipe as they travel to a mandrel on which they are braided, the wiping surface being defined by a surface of revolution around the mandrel and having a continuous orifice for supplying resin continuously around the wiping surface. Also disclosed is an electrical fuse including a fuse casing having a tubular wall including multiple-filament reinforcing yarns that have been braided in the tubular shape of the wall and a synthetic resin bonding the yarns together and impregnating the yarns, a pair of terminals secured to the ends of the fuse casing, and a fusible element inside the casing and connected to the terminals.

Abstract: A method of manufacturing a piston for transferring an output force to a member in responsive to pressurized fluid being communicated to a bore in a housing. The piston has a cylinder body made of a plurality of triaxial braided layers of carbon fibers which are placed on a mandrel with spacers located between the layers to form an annular projection of a first end and a taper of a second end. The carbon fibers are inpregnated with a thermoset resin and cured to define a unitary solid structure. Thereafter a cone and collar, throughwhich an output force is suppled to member, is attached to the second en dand the unitary structure inserted in the bore.

Abstract: A method for continuously vulcanizing a self-molding hose by external heating including the steps of first forming continuous strip of self-molding material which includes a heat-shrinkable woven fabric, a first vulcanized elastomer topping layer provided on a top surface of the heat-shrinkable woven fabric, a second vulcanized elastomer topping layer provided on an undersurface of the fabric with the second vulcanized elastomer topping layer being thinner than the first vulcanized elastomer topping layer and an unvulcanized elastomer topping layer provided on the undersurface of the second vulcanized elastomer topping layer. Then the continuous strip is overlappingly wound on a former to create a circular hose and the circular hose is continuously introduced into a gap between rotary drums of vulcanization apparatus at the same rate as the rate of the circular hose formation so that the circular hose is pressed flat, heated and vulcanized and converted into a flat hose.

Abstract: A flexible hose construction and method of making the same are provided, the flexible hose construction comprising an inner corrugated hose made of polymeric material and having a plurality of outwardly convex projections with recesses therebetween and extending from one end thereof to the other end thereof, an outer sleeve of reinforcing material disposed in telescoping relation on the inner hose, and a tube of polymeric material disposed between the sleeve of reinforcing material and the inner hose and extending in a generally straight-line manner from projection to projection of the inner hose so as to tend to prevent the sleeve of reinforcing material from entering into the recesses of the inner hose an amount that would end to substantially reduce the flexibility characteristics of the inner hose.

Abstract: A twisted FRP structure having sufficient strength and flexibility is produced by providing a rod member disposed centrally and twist a plurality of side strands twisted around the rod member in the same direction at a predetermined pitch. At least the side strand includes a composite strand having an FRP element from by impregnating fibers with an uncured thermosetting resin and a thermoplastic coating on such FRP element, the thermosetting resin being cured after the side strands are twisted around the rod member. The twisting pitch is not less than 25 times the outside diameter of the FRP element in the side strand.

Abstract: A rod-like yarn guiding heald is made of a compact thermoplastic reinforced with industrial continuous fibers. The fiber reinforcement is in the form of a flattened braided flexible tube. An eye opening is contrived by opening up the braided fiber strands. The yarn guiding heald is of light weight and high strength. A ceramic insert may also be inserted into the opening of the yarn guiding heald for special yarns.

Abstract: A method of making a fire hose including the steps of extruding a tube having inner 12 and outer coverings of elastomeric material on a woven jacket made from woven synthetic textile yarns and having a weft which is unusually highly crimped. The extruded tube is placed in a confining mould or sheath having an internal diameter substantially the same as the external diameter of the hose, curing the material of the tube by internal application of heat and pressure, pressing the outer covering into tight engagement with the sheath. The sheath effectively prevents radial expansion of the hose during the curing and the outer covering is thus embossed with the surface topography of the inner surface of the sheath upon removal of the sheath. The hose thus formed has good diametral swell properties and consequently reduces the frictional forces in relation to the amount of water flowing through the hose.

Abstract: A process for the production of profiles from composite fibrous materials, wherein the strands of fibrous materials continuously impregnated with liquid reaction resins are wrapped or braided immediately after impregnation or in a prehardening zone with drawn and/or preoriented and/or textured organic fibres or monofils or mixtures of organic and inorganic fibres or monofils and are hardened in a following hardening zone.

Abstract: The present invention discloses a glass covered electrical insulation having an inner lining of glass fibers coated with a flexible, high temperature, electrically insulating silicone polymer, the electrically insulating layer then has a second layer of glass fibers overbraided on it and bonded to it by the use of a heat treating process. A further teaching is the method of making the flexible sleeving and a method of use. The sleeving is particularly adapted for use in VPI processing and has superior flexibility as well as higher temperature capabilities than sleeving of the prior art.

Abstract: Fiber reinforced plastic tubing is formed by an innermost layer of braided strands that include longitudinal stud fill strands within the braid, a second layer of longitudinal strands, and a third layer of braided strands, all thoroughly encased in a monolithic mass of plastic matrix material that is not, itself, divided into layers. The tube is fabricated on a continuous basis by winding two sets of strands in opposite directions on a mandrel and braiding the two sets with each other and with stud fill strands that prevent that first layer of braid from stretching longitudinally and thereby tightening immovably on the mandrel. The strands are braided dry but are wetted with liquid plastic matrix material as the braid is compacted on the mandrel.

Abstract: A method of hose construction and product formed thereby consisting of an extruded thermoplastic core tube having ferrometallic wire reinforcement windings thereon which are closely wound and providing minute spaces between the wires. The reinforced core tube structure is elevated in temperature by an induction heater which concentrates heating in the wire reinforcement and transfers heat from the wire by conduction to the outer periphery of the core tube. Supplemental conventional heaters may be used in conjunction therewith to achieve substantial temperature elevation of the wire reinforcement. Thereafter a thermoplastic cover is pressure extruded over the heated wire reinforcement and forced through the minute spaces in the reinforcement into engagement with the core tube periphery. Cool-down establishes a bond between cover, wires and core tube and a mechanically locked, integral composite hose structure.

Abstract: The invention relates to a hose comprising an inner plastic tube (2) covered by at least one braiding of filaments disposed in helically crossed layers (5, 6) around the inner tube (2), characterized in that the filaments (7) are made of plastics and are so deformed in their right cross-section that the gap (8) between any two adjacent layers (6a, 6b) which extend in the same direction as one another is at least 100% filled. The invention also relates to a process for the production of the hose.

Abstract: A pipe of thermosetting resin, characterized in that it comprises a layer of curable thermosetting resin enclosed between a hose-shaped inner foil and a hose-shaped outer foil, which layer in its curable state together with said two foils forms the shape of a flexible foldable hose, in which shape the pipe can be laid in place and subsequently given its final shape and is made shape permanent by curing the thermosetting resin, said layer of curable thermosetting resin being reinforced by a fabric reinforcement braided of thread systems movable relative to each other, which fabric reinforcement owing to the relative movability of the thread systems can be widened and contracted to change the diameter of the pipe in the form of a flexible hose, and said thread systems being interlocked by the thermosetting resin in its cured state.

Abstract: A method of manufacturing soft tip catheters having inner rigid polymer layers and outer soft, pliable polymer layers. The method involves first extruding the rigid polymer at varying extrusion rates to form a cylindrical body having a depression at one or more prescribed locations. The outer layer is formed by extruding the soft, pliable polymer over the inner to fill in the depressions. The resulting cylindrical body is then cut to form individual catheters having soft tip as defined by a portion of the prescribed locations.

Abstract: The process for the manufacture of a tubular semimanufactured article made from plastic (synthetic resin) for the fabrication of sacks comprises at least one tubular extrudate made from a thermoplastic film, said extrudate reinforced with narrow strands or tapes made from plastic or the like and extruded around the circumference and/or along the length thereof, and a second tubular covering or jacket extrudate made from a thermoplastic film which is applied onto said first reinforced plastic film, whereupon the assembly is bonded together in a soft and warm condition. In this connection, said second tubular plastic film is applied in the form of at least one individual, preferably continuously delivered, film run or web, said film run being welded or bonded together at its edges, thus forming the tubular covering or jacket film.

Abstract: Method and apparatus for producing a fiber-reinforced rubber hose having an inner rubber tube, a tubular reinforcing fiber layer, an outer rubber tube, and a resin cover tube, which are formed in this order on a core mandrel. After the formed cover tube is cooled to a temperature sufficiently low to harden the resin to an extent that substantially inhibits expansion of the outer rubber tube in the hardened cover tube, the unvulcanized inner and outer rubber tubes are microwave-heated to soften the rubber tubes, and to cause a thermal shrinkage of the tubular reinforcing fiber layer, for thereby causing a portion of the inner rubber tube to be forced through a network of an interlaced structure of the reinforcing fiber layer into the outer rubber tube. After the unvulcanized inner and outer rubber tubes are vulcanized, the resin cover tube is removed, and the fiber-reinforced rubber hose is prepared.

Abstract: A method of fabricating a fiber-reinforced plastic article having first, second, and third cylindrical portions is disclosed. A helical braid is applied along a first cylindrical portion as a first cylindrical sleeve which conforms to and encases the outside surface of said first cylindrical portion. The second cylindrical portion is passed through the filaments forming the braid and the braid is collapsed into a first, substantially flat, double-ply braided ribbon which is then wrapped about the outer surface of the second intersecting portion. The helical braid is again applied along the first cylindrical portion and a second braided ribbon is then wrapped about the outer surface of the third cylindrical portion. The fibers are impregnated with a thermosetting resin which is cured to produce the article.

Abstract: Process for preparing preforms and composite articles from carbon fiber reinforced matrix resins braided to shape on a mandrel and then converting to final composite article by fully or partially curing in a mold followed by post curing if required.

Abstract: A heat deformable tube having a melt liner of noncross-linked, thermoplastic material, such that upon heating to a temperature high enough to cause the tube to return to its original shape; the melt liner melts and encapsulates the substrate.

Abstract: The invention relates to a process for the manufacture of hollow articles, in which a photocurable resin is introduced into a mold which transmits light, the mold is irradiated until the resin has polymerized to the desired depth, the remaining resin is allowed to run out and the partially polymerized layer is then fully cured. The hollow articles may be used in particular as expendable cores in the manufacture of plastics containers by the winding process.

Abstract: A process for producing hoses of laminated construction having a plastic inner tube is disclosed which comprises:- (a) extruding a thermoplastic resin on a mandrel to form an inner tube with a predetermined thickness, the mandrel being preformed of a thermoplastic resin or rubber and releasable from the inner tube, (b) laminating an outer tube integrally on the inner tube by extrusion of an unvulcanized rubber to form an integral hose body, (c) vulcanizing the hose body, (d) removing the mandrel from the vulcanized hose body. This hose is characterized by high resistance to load of impulse.

Abstract: The present invention discloses a glass covered electrical insulation having an inner lining of glass fibers coated with a flexible, high temperature, electrically insulating silicon polymer, the electrically insulating layer then has a second layer of glass fibers overbraided on it and bonded to it by the use of a heat treating process. A further teaching is the method of making the flexible sleeving and a method of use. The sleeving is particularly adapted for use in VPI processing and has superior flexibility as well as higher temperature capabilities than sleeving of the prior art.

Abstract: A method for continuously extruding an elastomeric material on the interior of a continuous tubular woven fabric in a loom, comprising motive means for creating relevant movement between the extruder and the woven fabric, sensing means for detecting stoppage of said loom, control means responsive to said sensing means directing said motive means to move said extruder relative to said woven fabric and a tubular woven fabric having an interior layer extruded directly onto the interior of the tubular woven fabric.

Abstract: There is disclosed a flexible mandrel for making tubular products comprising an elastomeric portion surrounding a reinforcing cable comprised of wire cables twisted around a non-metallic core. There is also disclosed a process for making a flexible mandrel and a process of making a hose using the flexible mandrel.

Abstract: To convey corrosive liquids, rubber hoses are customarily provided with an inner lining that is made of a synthetic material which is resistant to solvent. In order to achieve the previously unobtainable smooth, fold-free application of the thin plastic foil against the inner rubber layer of a hose, the present invention utilizes an extremely thin-walled contractible foil sleeve that is smoothly contracted upon a rigid fabrication mandrel. This foil sleeve then forms the base for the further build-up of the hose.

Abstract: A method of manufacturing fiber reinforced silicone elastomer hoses and the hoses (25) resulting from the method are disclosed. The method comprises the step of extruding an unreinforced silicone elastomer inner tube (13) containing two vulcanizing agents having different activation temperatures. The extruded inner tube (13) is partially cured by heating the tube to the activation temperature of the lower temperture vulcanizing agent. The partially cured inner tube (13) is mounted on a mandrel (19) and wrapped with a fabric reinforced, calendered sheet (21) of uncured silicone elastomer containing a vulcanizing agent. External pressure is applied to the wrapped tube while the wrapped tube is heated to activate the second vulcanizing agent of the inner tube (13) and the vulcanizing agent of the wrapping sheet (21).