Packing and Gasket Materials - United States (US)

Federal Supply Class (FSC): 5330

Federal Supply Group (FSG): 53 Hardware and Abrasives

NATO Supply Classification Class (NSC): 5330

NATO Supply Classification Group (NSG): 53 Hardware and Abrasives

Items Managed by United States (US)

FSC 5330 Packing and Gasket Materials - United States (US)

Includes General Purpose Oil Grease, Air, Liquid, Gas, and chemical Seals; Oakum; Prefabricated Gaskets and Seals designed for a single specific application.

Excludes O-Rings (FSC 5331); Bulk material items, such as; Rubber, Cork, and Asbestos Sheets and Strips (FSG 93); Liquid Gasket Materials (RTV, Permatex, etc.) (FSG 80); RFI and EMI Seals and Gaskets (FSC 5999), and all Seal Retainers.

Frequently Asked Questions (FAQ) for Federal Supply Class 5330

What is Federal Supply Class 5330?: FSC 5330 is the Federal Supply Class (formally known as NATO Supply Classification Class NSC 5330) in the USA for supply items codified in the category of Packing and Gasket Materials.
What is NATO Supply Classification Class 5330?: NSC 5330 is the NATO Supply Classification Class (also known as Federal Supply Class FSC 5330 in the USA) for supply items codified in the category of Packing and Gasket Materials.
Which Federal Supply Group is FSC 5330 in?: FSC 5330 is in Federal Supply Group (FSG) 53 which contains Hardware and Abrasives.
Which NATO Supply Classification Group is NSC 5330 in?: NSC 5330 is in NATO Supply Classification Group (NSG) 53 which contains Hardware and Abrasives.

Supply Items Included in Federal Supply Class 5330

What is a Cork Sheet? 54 Items: A Cork Sheet is a sheet of natural bark or a sheet of rolled or comppressed granulated cork having a cork gum, gelatin, or phenolic resin binder. It may include a fabric or other interliner. Cross-sectional sizes are limited to thicknesses of 1 inch (25.4 mm) or less and widths of over 6 inches (152.4 mm). See also CORK AND RUBBER SHEET; CORK STRIP; and CORK AND RUBBER STRIP. Excludes INSULATION BLANKET, THERMAL; and INSULATION BOARD, THERMAL.
What is a Cork Strip? 27 Items: A Cork Strip is a strip of natural bark or a strip of rolled or comppressed granulated cork having a cork gum, gelatin, or phenolic resin binder. It may include a fabric or other interliner. Cross-sectional sizes limited to thicknesses less than 1/2 inch (12.7 mm) and widths of 6 inches (152.4 mm) or less. See also CORK AND RUBBER SHEET; CORK AND RUBBER STRIP; and CORK SHEET. Excludes INSULATION BLANKET, THERMAL; INSULATION BLOCK, THERMAL; and INSULATION, THERMAL.
What is a Plain Encased Seal? 11136 Items: A Plain Encased Seal (SEAL,PLAIN ENCASED) is a pliable rubber, felt, leather, or composition ring-shaped element, split or solid; with or without spring or spreader, having a metal shell on all or a portion of at least two of the outer surfaces. It may be designed to be either bolt mounted or pressmounted between fixed and moveable parts to form a tight and effective seal by the pressure of the spring or spreader or the resiliency inherent in the element material. Excludes PACKING WITH RETAINER.
What is a Plain Seal? 14057 Items: A Plain Seal (SEAL,PLAIN) is a pliable rubber or composition ring-shaped element, split or jointless (solid) not encased in a metal shell, but having a spring, spreader and/or molded-in reinforcement. It is designed to be pressmounted between fixed and movable or moving parts to form a tight and effective seal.
What is an Oakum? 12 Items: An Oakum is a loose fibrous material made from hemp (line, tow or Benares Sunn) or jute fiber, treated or untreated with oil or pine tar, used for stopping leaks and caulking seams.
What is a Preformed Packing? 21437 Items: A Preformed Packing (PACKING,PREFORMED) is a circular shaped item with an aperture manufactured to predetermined dimensions and designed for use as a seal in stuffing boxes, packing nuts, and the like. It may be (1) any nonmetallic molded or formed ring (except solid (without joint) rings having a square or rectangular cross section); or (2) any shredded metal or metal foil type metallic or semimetallic rings. Excludes felt items but includes multimaterial items in which one of the materials is felt. For solid (without joints) nonmetallic items with a square or rectangular cross section, see WASHER (as modified) and GASKET. For rubber items specifically designed for weather-proofing doors, windows, chests, and the like see SEAL, NONMETALLIC ANGLE; SEAL, NONMETALLIC CHANNEL; and SEAL, NONMETALLIC, SPECIAL SHAPED SECTION. For circular (with aperature) nonmetallic items with a solid round cross-section see O-RING. Excludes CUP, COMPRESSION; GASKET; WASHER (as modified); and FELT, MECHANICAL, PREFORMED.
What is a Gasket? 105558 Items: A Gasket is a deformable material which prevents the passage of matter through the joint formed when two faces are joined. It may be metallic or nonmetallic, lubricated or impregnated, solid or hollow cross section. It may be made to any predetermined dimension and shape. Excludes flat disks, items made of felt material and items having joints. For round metal and plastic items with an aperture and a solid rectangular cross section, see WASHER, FLAT; SHIM; BEARING, WASHER, THRUST; and SPACER RING. Excludes DISK, VALVE; SEAL, NONMETALLIC ANGLE; SEAL, NONMETALLIC CHANNEL; SEAL, NONMETALLIC SPECIAL SHAPED SECTION; SHIELDING GASKET, ELECTRONIC; and RING, SEALING JAR.
What is a Packing Material? 2113 Items: A Packing Material is any material specifically designed and constructed to resist deterioration from the action of heat, gas, chemicals or liquids and used to create a tight seal. It is supplied in loose form or in coils, spirals, spools or cut lengths, usually having a square or round cross section. For rubber items having a round cross section, see RUBBER ROUND SECTION. Excludes ROPE, ASBESTOS; CALKING COTTON; and CALKING LEAD. See also PACKING, PREFORMED; and OAKUM.
What is a Packing With Retainer? 1739 Items: A Packing With Retainer is an item composed of a compressible nonmetallic ring which may be loosely fitted into a noncompressible retaining ring, or may be of one piece construction with the compressible ring molded and/or mechanically connected to the retainer. It is specifically designed to form a fluid tight seal when compressed by a packing nut, gland, and the like, between fixed surfaces and a cylindrical item passing through it. Excludes SEAL,PLAIN,ENCASED.
What is a Packing Assembly? 3955 Items: A Packing Assembly is any combination of items manufactured from PACKING MATERIAL to predetermined dimensions, or any combination of nonmetallic molded or formed shapes (other than solid rubber or synthetic rubber rings having a square or rectangular cross section) specifically designed and manufactured for use as a seal. The assembly may include metal lantern rings, metal separators, and/or end or adapter rings.
What is a Compressed Asbestos Sheet? 87 Items: A Compressed Asbestos Sheet (ASBESTOS SHEET,COMPRESSED) is a compressed sheet consisting of asbestos fiber uniformly mixed with a binder. It may be flat or in roll form. It is usually pliable and normally used as a gasket material. Sheets are limited to widths greater than 6 inches (152.4 mm). Excludes INSULATION BLANKET, THERMAL; INSULATION BLOCK, THERMAL; INSULATION BOARD, THERMAL; PAPER, ASBESTOS; and items designed for clutch and/or brake applications.
What is a Woven Asbestos Strip? 11 Items: A Woven Asbestos Strip (ASBESTOS STRIP,WOVEN) is a woven strip consisting of asbestos cloth usually impregnated with a filler compound. It may be flat or roll form and may also be interwoven with wire. It is normally pliable and frequently used as gasket material. Strips are limited to widths of 6 inches (152.4 mm) or less. Excludes INSULATION TAPE, THERMAL and items designed for clutch and/or brake applications.
What is a Cork And Rubber Sheet? 82 Items: A Cork And Rubber Sheet is a flexible sheet of compressed or rolled granulated cork having a rubber binder. It may contain a fabric liner. Sheets are limited to widths greater than 6 inches (152.4 mm) See also CORK AND RUBBER STRIP; CORK SHEET; and CORK STRIP. Excludes INSULATION BLANKET, THERMAL; INSULATION BLOCK, THERMAL; and INSULATION BOARD, THERMAL.
What is a Cork And Rubber Strip? 22 Items: A Cork And Rubber Strip is a flexible strip of compressed or rolled granulated cork having a rubber binder. It may contain a fabric liner. Strips are limited to widths of 6 inches (152.4mm) or less. See also CORK AND RUBBER SHEET; CORK SHEET; and CORK STRIP. Excludes INSULATION BLANKET, THERMAL; INSULATION BLOCK, THERMAL.
What is a Gasket Paper? 102 Items: A Gasket Paper (PAPER,GASKET) is an item consisting of a plant or animal fiber and binding compound, rolled or compressed into sheets or rolls, specifically designed and treated for use as a gasket material. See also PAPER (as modified).
What is a Packing Retainer? 13261 Items: A Packing Retainer (RETAINER,PACKING) is an item designed to fit over a packing gland by mating with a surface of a second part which together will retain into a narrow groove or confined space the PACKING, PREFORMED or O-RING, or an item designed to fit over a rod or shaft, to mate with a stuffing box to confine PACKING MATERIAL. It may function as a static or dynamic seal retainer with the packing located on, around, or in the centerline direction of the rod or shaft axis. It may have holes or joints for mounting, be threaded or unthreaded. See also PACKING NUT and PACKING NUT, STUFFING TUBE.
What is a Washer Assortment? 15 Items: A Washer Assortment is two or more different size and/or types of washers grouped together in a single package.
What is a Plain Solid Disk? 131 Items: A Plain Solid Disk (DISK,SOLID,PLAIN) is a circular item with two parallel bearing surfaces without hole(s) or groove(s). It has an outside diameter greater than its length, and may be fabric reinforced. Do not use if a more specific item name applies. For items primarily designed to rupture at a predetermined pressure, see DISK, RUPTURABLE. For items made of felt, see FELT, MECHANICAL, PREFORMED. For metallic or plastic items with a laminated cross section, see SHIM. Excludes DIAPHRAGM, VALVE, FLAT; DIAPHRAGM, VALVE, SPECIAL SHAPED; DISK, VALVE, NONMETALLIC; FILTERING DISK FLUID; and INSULATOR, DISK.
What is a Preformed Mechanical Felt? 1033 Items: A Preformed Mechanical Felt (FELT,MECHANICAL,PREFORMED) is an item manufactured to predetermined dimensions. It is either a precut strip or an item of various peripheral shapes and may contain bolt hole(s). It is used as a seal, wiper, mounting pad or for similar purposes. Excludes GASKET and PACKING PREFORMED.
What is a Metal Seam Sealing Cloth Tape? 45 Items: A Metal Seam Sealing Cloth Tape (TAPE,CLOTH,METAL SEAM SEALING) is a narrow strip of cloth impregnated with an adhesive sealing compound used particularly for sealing against pressure, such as pressurized cabins, riveted fuel tanks or other liquid containers. It is suitable not only as a sealer but also as a dissimilar metal insulator for the prevention of electrolysis causing galvanic corrosion. The adhesive compound may be covered with cloth or fabric, such as buckram interleaf, to prevent sticking in the roll and is discarded in use. Excludes TAPE, INSULATION, ELECTRICAL; TAPE, JOINT, WALLBOARD; TAPE, GUMMED; TAPE, ADHESIVE, RUBBER; and STRIP, COATED CLOTH.
What is a Wiper Ring? 1750 Items: A Wiper Ring (RING,WIPER) is a circular, single or multipiece, rigid, metallic or nonmetallic item having a centrally located hole with a sharp edge on the inside periphery. It is supplied in various cross-sectional shapes and is designed to be installed in a cylinder, shock strut, or similar device to remove excess oil, dirt, ice, and/or foreign material from a piston, ram, or sliding rod. Excludes PACKING, PREFORMED; RING, PISTON; and SEAL RING, METAL.
What is a Nonmetallic Seal Cap? 93 Items: A Nonmetallic Seal Cap (CAP,SEAL,NONMETALLIC) is a molded cup-shaped item having a small aperture in its apex. the aperture is designed for releasing the excess sealing cement applied in the cap prior to use. The item is designed to create a tight seal around bolt heads, nuts and rivets where a tight and effective seal is required, such as airplane integral fuel tanks. Also used for antichafing protection. Excludes BOOT, DUST AND MOISTURE SEAL and CAP, PPROTECTIVE, DUST AND MOISTURE SEAL.
What is a Coupler Seal Sleeve? 527 Items: A Coupler Seal Sleeve (SLEEVE,SEAL,COUPLER) is a cylindrical shaped item constructed of pliable nonmetallic solid or laminated materials. It is designed to fit around flanged or beaded end tubing, ducts, piping, and the like, to form a tight and effective seal against gases and liquids; when compressed with a clamp. For items used to convey air under low pressure, see HOSE, AIR DUCT. Excludes PACKING, PREFORMED; TUBING, NONMETALLIC; and BUSHING, RUBBER.
What is a Gasket And Preformed Packing Assortment? 88 Items: A Gasket And Preformed Packing Assortment is two or more different sizes and/or types of gaskets and preformed packing, grouped together in a single package and intended for individual repeated replacement and/or general use. For items intended for one time replacement in the repair of pumps, valves, engines, compressors, and the like, see GASKET AND PREFORMED PACKING SET; for items containing gaskets, preformed packing, and additional items such as washers and seals, see PARTS KIT (as modified).
What is a Gasket And Preformed Packing Set? 366 Items: A Gasket And Preformed Packing Set is two or more different sizes and/or types of gaskets and preformed packing, grouped together in a single package and intended for one item replacement in the repair of pumps, valves, engines, compressors and the like. FOR ITEMS INTENDED FOR INDIVIDUAL REPEATED REPLACEMENT AND/OR GENERAL USE, SEE GASKET AND PREFORMED PACKING ASSORTMENT; for items containing gaskets, preformed packing, and additional items such as washers and seals, see PARTS KIT (as modified). See also GASKET; and GASKET SET. Excludes GASKET ASSORTMENT; and PACKING ASSORTMENT, PREFORMED.
What is a Gasket And Shim Set? 37 Items: A Gasket And Shim Set is two or more different sizes and/or types of gaskets and shims, grouped together in a single package and intended for one-time replacement in repair of transmission, differentials, gear boxes, and the like. See also GASKET; SHIM and GASKET SET.
What is a Gasket Assortment? 195 Items: A Gasket Assortment is two or more sizes and/or types of gaskets grouped together in a single package and intended for individual repeated replacement and/or general use. See also GASKET SET.
What is a Gasket Set? 2963 Items: A Gasket Set is two or more sizes and/or types of gaskets packaged or grouped for issue as a unit for complete replacement. See also GASKET ASSORTMENT.
What is a Rubber Round Section? 326 Items: A Rubber Round Section is an item of natural and/or synthetic rubber of solid or cellular structure having a circular cross section. Items of cellular structure may be tubular or nontubular. It may have a wire or cord insert. For flexible tubular items of solid rubber structure, see TUBING NONMETALLIC. Excludes HOSE, NONMETALLIC and electric current carrying items.
What is a Cloth Insert Solid Rubber Sheet? 71 Items: A Cloth Insert Solid Rubber Sheet (RUBBER SHEET,SOLID,CLOTH INSERT) is a sheet material consisting of a vulcanized elastomeric material inclosing a sheet of nonmetallic cloth, or of alternate layers of nonmetallic cloth and elastomer with elastomeric faces. The elastomer is the primary substance and the nonmetallic cloth is inserted for stiffness and/or to prevent deformation under stress in its plane. It may be provided flat or in rolls. It is normally used as a gasket material. Sheets are limited to widths greater than 6 inches (152.4 mm). See also CLOTH, COATED; CLOTH LAMINATED; and RUBBER SHEET, SOLID.
What is a Metal Seal Ring? 2571 Items: A Metal Seal Ring (SEAL RING,METAL) is a circular shaped item designed to be installed in a specially prepared groove or counterbore to provide a low pressure seal. It may be supplied in various cross-sectional shapes and is cut through at one point to allow for installation and fitting. Excludes items whose primary function is to provide sealing, wiping, or wearing surface capabilities for piston configurations. See also RING, PISTON and RING, WIPER.
What is a Rubber Strip? 1913 Items: A Rubber Strip is an elastic material of compact (solid) or cellular structure having smooth, crepe or porous surface(s) and having an oval, parallelogram, square, rectangular or D-shaped cross section. It is produced in various thicknesses. Strips are limited to widths of 6 inches (152.4mm) or less. It may or may not have a nonrubber backing or a wire cloth or cord insert. For items having a round cross section, see RUBBER ROUND SECTION. Excludes RUBBER SHEET, INNER TUBE REPAIR. See also NONMETALLIC ANGLE; NONMETALLIC CHANNEL; NONMETALLIC SPECIAL SHAPED SECTION.
What is a Gasket And Seal Set? 712 Items: A Gasket And Seal Set is two or more different sizes and/or types of gaskets and seals, grouped together in a single package intended for one-time replacement in repair of engines, transmissions, differentials, gear boxes, and the like. See also GASKET; SEAL, PLAIN; SEAL, PLAIN ENCASED; and GASKET SET.
What is a Preformed Packing Assortment? 613 Items: A Preformed Packing Assortment (PACKING ASSORTMENT,PREFORMED) is two or more different sizes and/or types of preformed packing grouped together in a single package and intended for individual repeated replacement and/or general use. Excludes PACKING ASSEMBLY.
What is a Nonmetallic Angle Seal? 187 Items: A Nonmetallic Angle Seal (SEAL,NONMETALLIC ANGLE) is an item fabricated from NONMETALLIC ANGLE. It may be (1) formed to a specific shape with or without joints, (2) a single piece whose ends have been secured together to form a specific shape, or (3) a straight item fabricated to a specific length for a specific application with end cuts or joints. Items except for molded corners, end cut(s), and mounting hole(s), slot(s), press fit buttons and the like, must be of one continuous cross section. It may have fabric, cord, or metal reinforcement. It is specifically designed for use in applications where there is no relative motion between joined parts. Excludes BUSHING, NONMETALLIC; GASKET; and PACKING PREFORMED. For straight items with square end cuts and without mounting hole(s), slot(s), or press fit buttons, see NONMETALLIC ANGLE.
What is a Nonmetallic Channel Seal? 673 Items: A Nonmetallic Channel Seal (SEAL,NONMETALLIC CHANNEL) is an item fabricated from NONMETALLIC CHANNEL. It may be (1) formed to a specific shape with or without joints, (2) a single piece whose ends have been secured together to form a specific shape, or (3) a straight item fabricated to a specific length for a specific application with end cuts or joints. Items except for molded corners, end cut(s), and mounting facilities, such as mounting hole(s), slot(s), press fit buttons, and the like, must be one continuous cross section. It may have fabric, cord, or metal reinforcement. It is specifically designed for use in applications where there is no relative motion between joined parts. Excludes GASKET; GROMMET, NONMETALLIC; and PACKING, PREFORMED. For straight items with square end cuts and without mounting hole(s), slot(s), or press fit buttons, see NONMETALLIC CHANNEL.
What is a Nonmetallic Special Shaped Section Seal? 7368 Items: A Nonmetallic Special Shaped Section Seal (SEAL,NONMETALLIC SPECIAL SHAPED SECTION) is an item fabricated from NONMETALLIC SPECIAL SHAPED SECTION. It may be (1) formed to a specific shape with or without joints, (2) a single piece whose ends have been secured together to form a specific shape, or (3) a straight item fabricated to a specific length for a specific application with end cuts or joints. Items, except for molded corners, slot(s), press fit buttons, and the like must be of one continuous cross section. It is specifically designed for use in applications where there is no relative motion between joined parts. Excludes BUSHING, NONMETALLIC; PACKING, PERFORMED; PAD, CUSHIONING;and SEAL, PLAIN. For straight items with square end cuts and without mounting hole(s), slot(s), or press fit buttons, see NONMETALLIC SPECIAL SHAPED SECTION.
What is a Stuffing Tube Packing Assembly Kit? 64 Items: A Stuffing Tube Packing Assembly Kit (PACKING ASSEMBLY KIT,STUFFING TUBE) is a kit consisting of two PACKING ASSEMBLY to seal each end of stuffing tubes used for electrical penetration of bulkheads.
What is a Mechanical Equipment Seal Replacement Parts Kit? 4919 Items: A Mechanical Equipment Seal Replacement Parts Kit (PARTS KIT,SEAL REPLACEMENT,MECHANICAL EQUIPMENT) is a parts kit consisting of numerous items. The kit may contain seals, gaskets, packing, and/or retainers for repairing mechanical equipment. Excludes kits including tools, collars, pins, sleeves and associated hardware. Excluds PARTS KIT (1), SEAL REPLACEMENT, ARTILLERY.
What is a Nonmetallic Round Section Seal? 1600 Items: A Nonmetallic Round Section Seal (SEAL,NONMETALLIC ROUND SECTION) is an item fabricated from nonmetallic material designed to be used where there is no relative motion between joined parts. Items with a solid cross section must be a single piece whose ends may have been secured together to form a specific shape. It may be formed to specific shape with or without joints. It may be a straight item of a specific length with end cuts or joints. It may have a solid or tubular cross section. Except for molded corners, end cuts, and mounting facilities such as mounting holes, slots, press-fit buttons, or the like, the item must be of one continuous round cross section. It may have fabric, cord or metal reinforcement. For straight items with square end cuts and without mounting holes, slots or press-fit buttons see RUBBER ROUND SECTION and TUBING, NONMETALLIC. Excludes GASKET and PACKING, PREFORMED.
What is a Nonmetallic Strip Seal? 2986 Items: A Nonmetallic Strip Seal (SEAL,NONMETALLIC STRIP) is an item fabricated from nonmetallic material designed to be used where there is no relative motion between joined parts. Items having a square or rectangular cross section must be a single piece whose ends may have been secured together to form a specific shape. It may be formed to a specific shape, except round, with or without joints. It may have fabric, cord or metal reinforcement. Except for molded corners, end cuts, and mounting facilities such as holes, slots, press-fit buttons, or the like, the item must be of one continuous cross section. For straight items with square end cuts and without mounting holes, slots or press-fit buttons see RUBBER STRIP. For items with round cross sections see SEAL, NONMETALLIC ROUND SECTION. Excludes GASKET and PACKING, PREFORMED.
What is a Seal Retainer Sleeve? 208 Items: A Seal Retainer Sleeve (RETAINER SLEEVE,SEAL) is a rigid cylindrical item with external grooves to provide proper spacing for seals and/or rings as modified. Must have a bore for a shaft or the like. Excludes RETAINER, OIL SEAL and RETAINER, PACKING.
What is a Spiral Wound Gasket? 1948 Items: A Spiral Wound Gasket (GASKET,SPIRAL WOUND) is a circular or moderately noncircular shaped item with an aperture. It is constructed of spring-like metal strips, preformed into a vee shape, laminated with a soft filler. It is designed to seal between two nondeforming surfaces. It may have an inner and/or outer, solid or spiral wound compression ring(s).
RING,BASE 64 Items
RING,OIL CONTROL 44 Items
What is a Missile Launch Seal Assembly? 36 Items: A Missile Launch Seal Assembly (SEAL ASSEMBLY,MISSILE LAUNCH) is an item specifically designed to be attached externally to prevent damage to the missile structure from pressurized launch gasses. Includes preformed segments, baseplates, and attaching parts.
What is a Brush Type Seal? 48 Items: A Brush Type Seal (SEAL,BRUSH TYPE) is an item designed for sealing openings. It is fitted with natural or synthetic bristles preventing dust or dirt penetration and contributing to air draft reduction.
What is a Door Seal Replacement Parts Kit? 34 Items: A Door Seal Replacement Parts Kit (PARTS KIT,SEAL REPLACEMENT,DOOR) is a parts kit consisting of nonmetallic seals and associated attaching hardware such as screws, nuts, washer and other related items used to replace door seals.
What is a Seal Retainer? 2731 Items: A Seal Retainer (RETAINER,SEAL) is an item of various shapes and cross sections, usually flanged and designed to fit over a rod, shaft, or the like, for the purpose of encasing and posititioning a SEAL, PLAIN ENCASED or a SEAL, PLAIN. The flange is usually drilled for stud or bolt mounting. Item does not include the seal. Excludes RETAINER, PACKING.
What is an Inflatable Seal Assembly? 33 Items: An Inflatable Seal Assembly (SEAL ASSEMBLY,INFLATABLE) is a combination of items used in sealing fin stabilizers and the like. It may include items such as valve cap, valve spring, locking nut, air inlet tube and the like.
What is a Special Purpose Thermal Insulation? 1154 Items: A Special Purpose Thermal Insulation (INSULATION,THERMAL,SPECIAL PURPOSE) is an item composed of natural or synthetic material in various shapes and sizes. It is specifically designed to provide insulation for the outer skin and/or internal components of missiles, bombs, and the like, against the affect of aerodynamic heating and/or operating heat. See also INSULATION, THERMAL, AIRCRAFT.
What is a Preformed Packing Back-Up Ring? 393 Items: A Preformed Packing Back-Up Ring (BACK-UP RING,PREFORMED PACKING) is a circular shaped item with an aperture manufactured to predetermined dimensions, constructed with a rectangular cross section that may be solid, with joint, or in a helical form that facilitates spiral wrap installation. It prevents seal extrusion under pressure and is designed to fit on the down-pressure side of a gland groove with a PACKING, PREFORMED or O-RING.