Abstract: A method of making game racket frame of plastic compound material includes a tubular body, which is formed by a bendable inner tube wrapped orderly and windingly with the cured thermoplastic plastic thin films and the long fiber fabric sheets made up of a plurality of long fiber bundles. The tubular body is placed in a mold cavity of a molding tool, which is subjected to a heat corresponding to the melting point of the thermoplastic plastic thin film. A gas with a first predetermined pressure is introduced into the tubular body so as to force the molten thermoplastic plastic thin film to diffuse uniformly into the interstices of the fiber bundles. Another gas having a second predetermined pressure is introduced into the tubular body to force the outer shell of tubular body to attach intimately to the wall of mold cavity of the molding tool, which is then cooled to permit the removal of the racket frame made therein. The method produces a recyclable racket frame and no waste causing environmental pollution.

Abstract: A method of making a bicycle frame of plastic composite material includes a process in which an inner tube is wrapped orderly with at least a thermoplastic matrix layer and a long fiber reinforcing layer, so as to form a tubular object having a laminated outer shell. The tubular object is placed in a molding tool, which is then heated up to a temperature corresponding to the melting point of the thermoplastic matrix. Under the condition that the heating temperature is maintained, a pressurized gas having a pressure is introduced into the tubular object in such a manner that the pressure is increased progressively and stepwise for a predetermined period of time. The molding tool is finally cooled to permit the removal of a newly-formed bicycle frame, which is light in weight, strong and tough.

Abstract: Improved multi-wall containers and pipes for transporting fluids which have to be protected against leakage and mechanical forces, have an inner and outer wall separated by a continuous foam layer integrated into the containers. Improved strength and resistance to axial inertial pressure is provided by the method of manufacture using chopped glass fibers, continuous windings of glass fibers and suitable polyester resins and circumferential ribs spaced at stress points and integrally incorporated into the containment walls. Vessels produced according to the methods of the invention have a moment of inertia strength of about 4.67 in.sup.4 substantially eliminating torquing, buckling and rupture.

Abstract: A tape wrap system adapted for protecting metal tubular articles, particularly pipes, from corrosion comprising in order, a primer coating covering the surface of the article, an innerwrap over the primer coating and an outerwrap placed over the innerwrap, the innerwrap comprising a polyolefin layer carrying an adhesive layer on its inner surface and a layer comprising a heat fusible material on its outer surface, or a single layer comprising a blend of a polyolefin and a heat fusible moiety carrying an adhesive layer on its inner surface, the outerwrap comprising an impact-resistant polyolefin layer having a heat fusible layer on both surfaces or the inner surface thereof, or a single layer comprising a blend of an impact resistant polyolefin and a heat fusible material; the tape wrap system fusing the innerwrap and outerwrap together when heated and thereafter cooled to form a uniform, continuous and completely closed protective coating which fully protects the article against corrosion and other external d

Abstract: To make a laminated flexible bearing constituted by rigid reinforcing layers made of composite material alternating with layers of rubber or elastomer, each reinforcing layer is formed by winding a resin preimpregnated thread directly on the underlying layer of rubber or elastomer. Advantageously, the flexible bearing is made by alternating layers formed by winding a resin pre-impregnated thread and layers formed of non-vulcanized rubber or elastomer, after which the resin is polymerized and the rubber or elastomer is vulcanized simultaneously.

Abstract: A method of making a pipe-like member such as a fishing rod and a golf club is disclosed. According to the method, a tape-like prepreg is formed by overlaying each other a first fiber layer comprised of fibers aligned along a longitudinal direction of the layer and a second fiber layer comprised of fibers aligned in a direction substantially normal to the fiber alignment direction of the first fiber layer. Then, the tape-like prepreg is wound about a mandrel with a turn of the prepreg being widthwise overlapped with an adjacent turn of the prepreg. Thereafter, the assembly is sintered.

Abstract: A method and apparatus for wrapping the liner of a tape, which has been peeled from the backing of a tape, around a pipe or other object in the same operation that the backing is applied. The apparatus includes a frame having at least two spaced apart bars which direct the path of the liner to an offset position which is parallel to and behind the portion of the backing which is currently being applied to the pipe. The liner is then wrapped around the pipe over the backing which has been wrapped around the pipe just in advance of the liner. The liner may also be perforated or otherwise treated before application to the pipe.

Abstract: A method and apparatus for producing flexible tubes of desired length from several strips of rubber and/or fiber reinforced rubber. The apparatus comprises a wrapping machine and a vulcanizer arranged in series on a common axis along which a core can move.

Abstract: An apparatus for continuous manufacture of bent rods having a shaped cross section from a reinforced stabilizing material, produced inside a supporting mold wound on a mandrel and containing reinforcing elements impregnated with stabilizable material. The material is stabilized over at least a portion of a length of the mandrel, with the bent rods being adapted to be used in reinforcements for flexible tubing.

Abstract: Dynamoelectric machines characterized by lengthened ground potential leakage current paths, desirable mechanical conformations, mechanical integrity when subjected to expected centrifugal forces, and ease of manufacture. One process involves establishing an extended path for commutator leakage currents with a path extending structure, establishing a cantilevered insulation skirt about the in-board or armature coil end of a commutator, and securely fastening such skirt to the commutator. The material utilized in making the skirt is one: that has electrical properties that permit it to withstand leakage currents without tracking; that for practical purposes is non-burnable, so as to resist flashovers or sparking; and that has the ability to withstand elevated temperatures that are encountered within dynamoelectric machine. The skirt is provided with openings therein and sandwiched between two glass based bands that adhere to another through the openings and thus lock the skirt in place on the commutator body.

Abstract: The present invention relates to a unique fiber-reinforced metallic tubular element, along with a unique method for producing such tubular elements on a production basis. The tubular element includes a cylindrical aluminum tube surrounded by a fiber composite sleeve which includes a plurality of individual reinforcing graphite fibers oriented parallel to the longitudinal axis of the tube and uniformly positioned about the circumference of the tube. In the preferred embodiment of the invention, an isolation layer is positioned between the graphite reinforcing layer and the outer surface of the aluminum tube, and a protective covering layer of fiber material surrounds the tube and is adhered to the outer surface of the graphite reinforcing layer. In the preferred method of the present invention, a plurality of cylindrical metal tubes are coupled to one another in an end-to-end relationship by a plurality of joining plug members to form a longitudinally extending series of metal tubes.

Abstract: A composite golf club shaft and the method of constructing the shaft is disclosed. The hollow circular shaft includes a standard butt end having a constant outside diameter along a length of the shaft and a tip end having a constant outside diameter sustantially larger than the tip of a standard shaft, with the constant diameter of the tip end and butt end extending along predetermined lengths of the shaft. An intermediate section of the shaft tapers between the diameters of the butt and tip ends. The shaft is manufactured by wrapping a group of circumferential sections about a mandrel, each layer comprising either standard modulus carbon-graphite fibers or fiberglass fibers in a matrix, with the finished product being heat-cured to produce a golf club shaft.

Abstract: Monofilament threads which are wound around a thermoplastic synethetic resin core tube to form one or more reinforcement coils are generated as they are wrapped around the core tube by liquid crystalline polymer material emerging from respective spinning nozzles which rotate around the core tube while a difference in speed is maintained between the speed at which the reinforcing plastic emerges from the nozzle and the monofilament thread is wound on the core tube to maintain a stretch in the monofilaments.

Abstract: The invention relates to a method for applying a protective coating to a substrate, such as metallic pipe, which comprises applying onto the substrate a liquid curable polymeric composition capable of curing to a substantial extent within about 24 hours at less than about 80.degree. C., then applying one or more polymeric layers, the innermost of which is capable of interacting with said curable composition, and permitting the composition to cure. In certain embodiments the polymeric layer is applied as a polymeric article, in other embodiments a multiple layer polymeric covering is applied over the curable composition.

Abstract: In a bicycle frame comprising a plurality of frame members which are selectively joined together at the ends thereof, each of the joints which support the head tube, the seat and the crank housing is a lug joint comprising a plurality of organic fiber layers partially wrapping the joined end portions of the frame members, the fibers composing each layer being oriented at different angles from the fibers in the adjacent layers, and all of these sheets being impregnated with resin which hardens to secure the sheets to the frame members. Web portions of these fiber layers also enclose a portion of the space between wrapped portions of the frame members, and each of these spaces is filled with a suspension of microballoons in hardended resin which cooperates with the web portions of the fibers layers to brace the joined frame members against movement toward each other during use of the bicycle.

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: An inflatable packer construction where the inflatable elastomer element is; (1) constructed from the same type of rubber compound from end-to-end the rubber is cured differentially from end-to-end so that inflation is from one end to the other end; (2) is constructed of rubber having different characteristics from end-to-end so that the cured rubber will inflate from one end to the other end; (3) is constructed of rubber having a release agent between one end of the rubber and a mandrel so as to release one end of the rubber first from the mandrel upon inflation; (4) is constructed of rubber having different thicknesses from end-to-end so that one end inflates sooner than the other end; or (5) is constructed of rubber with a segment of the length of the element having a releasably confining element.

Abstract: A method of making high efficiency, flame resistant polyimide foam insulation particularly suitable for insulating plastic pipes and forming ducts. Typically a sheet of polyimide foam which has been foamed unconstrained is placed between opposed caul plates, squeezed to a thickness less than the original thickness and heated to stabilize the new sheet thickness. Face sheets coated with a polyimide adhesive can then be placed against the stabilized foam faces and heated between plates to bond the face sheets to the foam. Also, a sheet of foam which had been impregnated with polyimide resin precursor can be placed against the stabilized sheet and the resin precursor simultaneously cured and the sheet bonded to the stabilized foam. A variety of flat, tubular or other shapes can be made by this method. The resulting insulation panels, tubes or the like have greatly improved flame resistance and excellent thermal insulation characteristics.

Abstract: Cryogenic vessels provided with improved thermal insulation by spirally generating two layers of thermal insulation thereon; permits thicker insulation without requirement of increased space and heavier equipment.

Abstract: A fishing rod having a portion on which a leg portion of a fishing reel is mounted is composed of three layered structure integrally formed by a thermosetting manner and comprising a prepreg sheet or woven fabric layer prepared by impregnating thermosetting resin into high tension or strength fibers, a glass fiber reinforced sheet layer prepared by impregnating thermosetting resin into glass fibers, and a carbon fiber reinforced sheet layer whose fibers extend in a single orientation prepared by impregnating thermosetting resin into carbon fibers. The three layers constitute a thickened portion on which the reel is mounted. Screw threads are formed throughout the entire axial length of the thickened portion and two nut members are screw-engaged with the screw threads in an axially opposing manner to be axially movable.

Abstract: A method for making a belt for use in papermaking includes a series of steps. A sheet of uncured urethane is wrapped on a polished mandrel. A woven fabric sleeve to serve as a supporting carcass is placed over the first sheet and shrunk onto it. A second sheet of uncured urethane is placed over the woven fabric sleeve. A nylon web is wrapped tightly around the second layer and the entire wrapped mandrel is heated, curing the urethane sheets and entirely bonding the sheets to encapsulate the fabric sleeve. The nylon wrap is removed and the surface of the cured urethane is ground.

Abstract: A double-wall tank having inner and outer walls bonded to connecting hollow annular ribs. Passageway means through the ribs enable leak-detecting liquid to fill the spaces between ribs, within ribs, and between end caps.

Abstract: The present invention resides in a method for producing a carbonated beverage can which has acceptable creep, modulus and yield strength values, which comprises a can body, which is made up of a core of a thermoplastic material, at least two layers of non-fibrous, extruded polyolefin film which has either been monoaxially stretched or biaxially stretched, [and which are wrapped around the core singularly or in plys at opposite plus/minus angles in relationship to each other to yield disproportionate stress resistance vectors for hoop and axial stresses present in said body at a 2:1 ratio] one layer of which is wrapped around said core singularly or in plys at an angle with respect to said core of from about +60.degree. to about +80.degree. and the other of said two layers is wrapped around said core singularly or in plys at an angle with respect to said core of from about -60.degree. to about -80.degree.

Abstract: The invention provides a method for forming a composite material tube connection.On a rubber skin 1 are wound inserts 3 and 4 which form the extra thick portions required for snap fitting of the tubes, of the male end piece and of the female end piece, on these inserts and on the current part of the tube fibers 5 are wound circumferentially, on the tube is fitted a sleeve 6 previously formed, on the female end piece are bound strips 7 also formed previously, and a stop heel 10 is formed on the male end piece by a new winding.

Abstract: A method for producing pipeline having a thermally insulating coating in which a continuous matrix of water-impermeable material has dispersed throughout it hollow microspheres or cellular particles which improve on heat insulating properties of the basic matrix.

Abstract: The invention relates to a method for applying a protective coating to a substrate, such as metallic pipe, which comprises applying onto the substrate a liquid curable polymeric composition capable of curing to a substantial extent within about 24 hours at less than about 80.degree. C., then applying one or more polymeric layers, the innermost of which is capable of interacting with said curable composition, and permitting the composition to cure. In certain embodiments the polymeric layer is applied as a polymeric article, in other embodiments a multiple layer polymeric covering is applied over the curable composition.

Abstract: A tubular metal object is rotated about its longitudinal axis and a layer of tape and synthetic thermosetting resin is wrapped around the object at room temperature. The object is inductively heated substantially uniformly through its thickness a plurality of times progressively from one end to the other subsequent to the wrapping to a temperature sufficient to allow the resin to flow on the outer surface of the object. The object is further inductively heated to a temperature at which the resin will cure, and the object is then cooled to room temperature.

Abstract: The method of making a non-metallic bearing assembly by bonding a first layer of uncured rubber that is wrapped on a mandrel to a fiberglass layer whose outer wrappings are impregnated with epoxy resin. The fiberglass outer layer is cured first to form a rigid outer plastic shell and then the uncured rubber is vulcanized to give an inner rubber sleeve whose inner periphery has polygonal contour which is the cross sectional configuration of the mandrel. An inner layer of fiberglass, cement impregnated, interconnects the fiberglass outer plastic shell to the inner rubber sleeve.

Abstract: A magnetic core containing amorphous metal, suitable for use with electrical inductive apparatus, such as transformers, and methods of constructing such a magnetic core. The desired physical dimensions of the magnetic core are maintained, without adversely stressing the core, by a composite, conformal coating applied to the core edges. The composite coating includes a rigid high strength outer structure and a low stress, adhesive inner structure which cooperatively provide mechanical support and stress protection for the magnetic core, while maintaining its configuration.

Abstract: A tire breaker comprising at least two breaker plies is assembled on a carrier ring which is movable between ply fitting stations.The ring is mounted on an arm which swings the ring through 90.degree. to each fitting station where the ply is supported on a table. Each end of the ply is then moved from the table on to the ring by means of grippers, and rollers then traverse the ring to ensure that the ply is positioned accurately. The joints formed in successive plies are diametrically opposed to one another.

Abstract: A method of making an elastomer lined composite vessel or portion of such vessel is disclosed. The method comprises causing a thin, tacky ribbon comprising an elastomer (preferably curable) to continuously so encircle a center rotational axis of a mandrel as to adjacently position and tack together integral segments of the ribbon substantially circumferentially relative to this center rotational axis thereby forming a layer of the elastomer about the mandrel; applying a shell comprising filaments and thermosettable resin to the layer of elastomer; curing the thermosettable resin (preferably in stages if the elastomer is curable with a later stage including cure of the elastomer) to provide the vessel or portion of the vessel.

Abstract: A shaft produced by the steps of rolling inorganic fiber cloths around a plastic resin base body into a cylindrical shape to form a shaft body, coiling two sets of carbon cloth tapes in the opposite directions around the shaft body, and impregnating resin into the shaft body and carbon cloth tapes to integrate them into a single body. The shaft obtained by the method is light and strong and shows excellent resiliency. The shaft is particularly advantageous and reliable for golf clubs, fishing poles, and the like.

Abstract: A lightweight ceramic refractory covering for water cooled members forming the structural portion of a metalliurgical furnace which is thermally insulating and resists wet scale attack, corrosion and vibrational stresses. The covering comprise an inner layer of thermal insulating ceramic refractory fiber blanket, an open weave ceramic cloth about the blanket, an inner layer of veneering mortar, compressed rings or strips of ceramic fiber material, and a hot face layer of veneering coating.

Abstract: A thermoplastic hose is extruced, longitudinally, but in opposite (thinned) locations, and the resulting two semi-circular sheets are flattened, superimposed with an offset, and wrapped around a rotating and axially advanced pipe. The hose may be extruded from above or from the side. The method and apparatus is applicable also for high-density PE (e.g., 0.95).

Abstract: A method of manufacturing a molded coil for use in an electric apparatus such as a molded transformer or a reactor. The method includes the steps of covering a winding with an insulating prepreg, curing the prepreg under heat, and casting a synthetic resin around the prepreg. The method makes it possible to minimize any thermal stress that may develop in the molded resin layer.

Abstract: For forming a perforated pipe a method is employed which includes winding on a mandrel having multiple spaced protrusions thereon angularly related strips arranged between the protrusions. These strips cooperatively define openings through which the protrusions extend. The strips are formed of fibres which are impregnated with a settable resin or plastic which combine with the fibres to form a tube adequate to resist a pressure of about 600 p.s.i. Because the protrusions are employed the fibres can be so impregnated as to be resin-rich. The openings may be screened with resin-poor granules arranged in vaulted configuration. A further strip may be wound around the foregoing arrangement to hold the granules against the resulting pipe.

Abstract: A novel method for producing a composite pipe having a desired wall thickness by using an endless steel belt as a mold which moves axially while rotating in the circumferential direction of a mandrel. In this method, a thickness regulating device spaced a predetermined distance from the outside surface of the endless steel belt is used to adjust the wall thickness accurately to the desired value. Examples of the thickness regulating device are a cylinder roll, a taper roll, and a conveyor belt.

Abstract: A plurality of lengths of fibers may be disposed into a sheet-like array with the fibers being spaced from each other and defining channels therebetween. A pair of membranes is brought into adhering relation with opposed sides of the fibers of the sheet-like array to form a multichanneled flow device.

Abstract: A large diameter suction and discharge hose capable of withstanding compressive end loads is formed of reinforced elastomeric material and includes a fitting at each end comprising a flange butt connected to a cylindrical nipple. The nipple includes an area of reduced outside diameter between its flange and opposite end to aid in retention of the nipple to the hose. The inner tube and inner reinforcing plies extend through the bore of the fitting and are adhered to the end face of the flange of the fitting. Intermediate reinforcing plies extend over the cylindrical nipple and are forceably retained by anchoring means which extend over annular grooves provided in the fitting. A helically wound heavy gauge wire extends between the back faces of the flanges and is embedded in elastomeric material. At least one outer ply layer is provided over the helically wound heavy gauge wire. An outer cover layer of elastomeric material completes the hose. A method of making such hose is also described.

Abstract: An automatic ply applying apparatus and method for forming an elastic annular body, such as a vehicle tire, by transporting each ply to a former, retaining a portion of the ply adjacent to the leading end of the former, applying the leading end portion of the ply to the peripheral surface of the former and applying the remaining portion of the ply to the peripheral surface of the former during rotation of the former.

Abstract: This invention relates to a new method for manufacturing a SF.sub.6 pressurized gas continuous spacer cable, and improvements which reduce costs and improve quality control of high voltage cables. The conductor is passed through taping machines for surrounding the conductor with a continuous insulating spacer and through taping machines for applying a conducting shielding material which partially covers the spacer. The insulated and shielded cable is continued on in the same production line into conduit which is laid out horizontal in long lengths or is extruded loose-fit over the cable. The cable is then subjected to vacuum while in the conduit. Terminations are applied. Seals are tested for leaks. The cable is filled with SF.sub.6 gas to a high pressure. The cable is tested at 1.5 times its operating voltage to ground for 30 minutes without failure.

Abstract: Pipe coating apparatus is disclosed. In the preferred and illustrated embodiment, a laterally deployed conveyor belt rotating around a pair of rollers passes beneath the pipe to be coated. Coating material is supplied into a hopper above the belt. The hopper includes positioned slots for receiving reinforcing mesh therein and locates the reinforcing mesh in an extruded ribbon of coating material supported by the conveyor belt and applied to the pipe in helical turns. The application of multiple turns of reinforcing mesh plus shaping of the extruded ribbon enables a thicker layer of coating material to be applied to the pipe, and it is reinforced with multiple layers of reinforcing mesh wire.

Abstract: A carbon fibre reinforced carbon article is prepared by wrapping carbon fibre cloth around a carbon fibre reinforced carbon core and then depositing elemental carbon on the core and in the cloth to bond the cloth to the core, leaving substantial interstices in the covering layer of cloth.

Abstract: A method for joining a composite material shaft, such as a graphite epoxy or fiber glass driveshaft, to a metal end member is disclosed, wherein said joint is capable of withstanding large ranges of temperature and humidity, can handle high torque and has high resistance to fatigue. The design of parallel grooves on the end of a metallic sleeve concentrically aligned within the shaft is amenable to mass production. The first layer of fibers of the composite material shaft is preferably wound perpendicular to the orientation of the grooves. On the other end of the metallic sleeve is carved a scalloped pattern which facilitates concentric alignment of the sleeve on the tooling mandrel and helps to reduce shear stress between the sleeve and shaft. A method for mass production of shafts with metallic end joints attached employs an elongated spinning mandrel and pre-preg tape wound at high speed.

Abstract: A method of reconstituting an external conductor of a coaxial cable which stands up well to bending and has good electromagnetic propagation. Solid non-perforated or woven strips are wound in a helix along the whole length of the part which is to be repaired and the ends of the intact external conductor and said strips are glued on these ends with an electrically conductive glue. Application to coaxial telephone cables.

Abstract: A tubular fiber reinforced composite shaft is formed (as described) which integrally incorporates a metal sleeve or connection at the end thereof. Initially a metal sleeve having circumferentially spaced recesses on the outer periphery thereof is positioned upon a segment of a mandrel. Fibrous material bearing a non-solidified resinous material is applied around the mandrel and around the recesses in the sleeve. Portions of the previously applied fibrous material bearing the non-solidified resinous material are pressed into the recesses. Additional fibrous material bearing the non-solidified resinous material is applied to the previously applied fibrous material. The resinous material next is solidified to form a tubular composite shaft whereby a secure torsion-transmitting connection is made with the sleeve, and the mandrel is removed.

Abstract: A porous acoustic element is disclosed having a configuration comprised of individual cross-wound porous layers of widely varying porosity, with transition plenum layers interposed therebetween having a configuration so as to prevent formation of blockages and small area openings which would be created by a direct overlay winding of differing pitch. The porosity of each wound layer increases in successive layers to compensate for expansion of the gas as it flows through the element. The resulting porous element allows gaseous flow therethrough, with maximum pressure energy dissipation and controlled velocity to minimize aerodynamic noise created by flow through valves and other flow restrictions. A specific embodiment is disclosed in which the porous layers are created by variable pitch wire ribbon cross windings and the transition layers are provided by wire mesh having relatively large openings.

Abstract: A tubular fiber reinforced composite shaft is formed by providing a metal sleeve having a plurality of circumferentially straight surface segments on the outer periphery thereof. The sleeve is positioned upon a segment of a mandrel. Fibrous material bearing a non-solidified resinous material is applied to the mandrel and the circumferentially straight surface segments of the sleeve. The resinous material is solidified with portions thereof lying flush against the circumferentially straight surface segments to create a torsion-transmitting connection with the metal sleeve.

Abstract: A method is disclosed of coating articles of manufacture to prevent corrosion which comprises applying a thermoplastic coating material to the article, applying a layer of fibrous material over the coating material, wetting the layer of fibrous material, and heating the three components, whereby contraction of the fibrous material, during heating, will compress the coating material and counteract its deformation tendencies such that it is well bonded to the article. The thermoplastic coating material is preferably applied in the form of a coating tape comprising the thermoplastic coating material and a thermoplastic adhesive and is used to provide a protective coating for underground pipe.

Abstract: A tubular composite structure for transmitting forces comprises a metal tubular core, preferably of aluminum, having a layer of structural metal adhesive on the exterior surface of the core. On top of the structural adhesive layer are alternating laminae of resin impregnated unidirectional reinforcing fibers, particularly carbon or graphite fibers, and of woven fiberglass, beginning with a layer of woven fiberglass followed by a lamina of resin impregnated continuous unidirectional reinforcing fibers and continuing in alternating fashion but ending with a final layer of resin impregnated continuous unidirectional reinforcing fibers, each successive layer of resin impregnated continuous unidirectional fibers having the fibers oriented at an angle of between about 5.degree. to 12.degree. with respect to the longitudinal axis of the metal tube and in opposite orientation with respect to the next preceding layer. The fibers in the woven fiberglass layer are oriented at 0.degree. and 90.degree.