Electrical Insulators

Custom Gasket Mfg. is a leading supplier of high-quality electrical insulators and shields.

Our company’s reputation for excellence has been built on our ability to provide our valued customers with the most effective manufacturing solutions to meet their most demanding applications. Our main objective is to continuously exceed our customer’s expectations by providing them with high-performance gaskets and sealing products, competitive pricing, on-time delivery and exceptional customer service. Custom Gasket Mfg. is committed to consistently meet all of your blueprint specifications and tolerance requirements.

Custom Gasket Mfg. specializes in precision electrical insulator components for a wide range of applications and industries worldwide. We offer custom electrical insulators by means of die cutting, waterjet cuttinglaserjet cutting and flash cutting. We also provide numerous secondary operations including scoring, creasing, bending, folding, embossing, ink and foil stamping, and pressure sensitive adhesive (PSA) backing to meet your manufacturing requirements.

Custom Gasket Mfg. takes pride in its ability to consistently produce high-quality, custom insulating parts that are used in applications including switches, timers, lighting fixtures, transformers, electronic instruments, electrical devices, electrical enclosures, controls, and a variety of other electrical applications. Custom Gasket Mfg. offers high-performance insulating films that meet flame and chemical resistant, UL approved standards. Custom Gasket’s technically-oriented professionals have extensive knowledge of insulating materials and work closely with customers to create custom electrical insulators to meet their exact specifications.

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Custom electrical insulators

Electrical Insulation Materials

Electrical insulators are manufactured from materials which restrict the flow of an electric current. They support electrical conductors without passing the current through. These particular materials also protect electrical conductors from coming into contact with people or tools and provide excellent insulation for electrical applications. Custom Gasket Mfg. insulators and shields are constructed from RoHS compliant materials. Both UL 94 VTM-0 and UL 94 V-0 approved products are available. Resistance to a wide range of chemicals along with low moisture absorption makes the application of these products ideal for printed circuits. We work directly from your blueprint in order to provide the most accurate product within tolerance. This ensures that your electrical insulator will meet and exceed your expectations.

Custom Gasket Mfg. maintains a full line of electrical insulation materials. We fabricate electrical insulators, such as; gaskets, seals, washers, strips, and custom designed intricate shapes. Electrical insulation materials are available in a broad range of thicknesses, hardness, densities and colors. Most insulating materials are available with or without pressure sensitive adhesive (PSA) backing. The most common insulating materials used include:


Custom Die Cut Mylar Gaskets

Mylar® is a polyester film. It is extraordinarily flexible, strong and durable film with an unusual balance of properties, making it an extremely versatile material. It can perform as a highly reliable and stable insulating material and can also be used as a packaging material for the shipping of products such as electronics. The excellent dielectric strength, moisture resistance and physical durability make Mylar® a standard material for various industrial applications. Custom Gasket Mfg. provides Mylar® with or without pressure sensitive adhesive (PSA) backing.

Kapton® Polyimide Film

Kapton Film Insulators

Kapton® is a polyimide film developed by DuPont™ which can remain stable in a wide range of temperatures. Its thermal conductivity properties make it ideal for use in controlling and managing heat in electronic assemblies such as printed circuit boards. Kapton® MT offers an excellent combination of electrical properties, thermal conductivity and mechanical toughness for its use in electronic and automotive applications. Kapton® has high dielectric strength and high tear strength. Kapton® has a unique combination of electrical, thermal, chemical and mechanical properties that withstand extreme temperature, vibration and other demanding environments. Kapton® is used in a broad range of industries including, consumer electronics, solar photovoltaic and wind energy, aerospace, automotive, electrical controls, electrical machinery, telecommunication, and food equipment. It is also commonly used in specific electronic applications such as; insulation pads, heater circuits, power supplies, ceramic board replacement, insulating circuit boards, heat sinks, fiber optic cable, and semiconductor manufacturing.

Nomex® 410

Nomex 410 Insulators

Nomex® Type 410 is the original form of Nomex® paper (by DuPont™). It is a high temperature aramid paper. Nomex® insulators have high inherent dielectric strength, mechanical toughness, flexibility and resilience. They are used in the majority of electrical equipment applications. Custom Gasket Mfg. produces a wide range of insulations in forms of gaskets and washers from Nomex® 410 material.

Fish paper

Fish paper is extremely durable and commonly used for electrical insulation. It is typically die cut to create unique components for specific electrical applications. It is frequently used in electrical devices and enclosures. It has an electrical insulation Class 110°C mechanical and Class 115°C electrical rating. Fish paper has resistance to electric tracking and its heat resistance is superior to unconverted cellulose electrical insulation.


This board is a rigid, dense multi-ply material constructed from unbleached kraft pulp and acrylic polymer. It has the UL-94 Flammability Classification of 94HB. It is rated for a working temperature up to 230°F (110°C). It has excellent dielectric (250 volts / mil) and mechanical strength, low water absorption, high punch-ability and fold-ability. This material is recommended especially for applications requiring fold lines and creases in material thickness greater than 0.020 in. (0.50mm). VHR-115® will not break when folded, unlike fish paper. VHR 115® is an industry accepted substitute for fish paper, particularly in the thicker material range. It has excellent dielectric and mechanical strengths, low water absorption and is free of conducting particles, chemical impurities and foreign matter. Its chemical cleanliness accounts for its excellent aging characteristics in air up to 115°C. VHR-115® can be used in numerous coil, transformer, motor, electrical hardware and electronic applications where excellent dielectric and physical strengths are required. VHR-115® is approved by Underwriters Laboratories reference E-31556 (M) electrical use at 115°C and mechanical at 110°C.


Die Cut Hitex Insulators & Foil Stamped

Hitex® is a dense, rigid material produced in multi-ply construction from unbleached Kraft pulp. It has excellent dielectric and mechanical strengths, low water absorption and is free of conducting particles, chemical impurities and foreign matter. Its chemical cleanliness accounts for its excellent aging characteristics. Hitex® can be used in numerous coil, transformer, motor, electrical hardware and electronic applications where excellent dielectric and physical strengths are required.


Valox® flame retardant film offers excellent insulation to a host of electrical applications. Pressure sensitive adhesive (PSA) backing can be applied to any Valox® gasket. Valox® is available in thicknesses of 0.075mm to 0.75mm.


PTFE Insulators

PTFE is one of the best thermally established and non-conducting plastic materials making it suitable for electrical insulators in circuit boards. PTFE can be die cut into gaskets, washers, or strips to provide insulation for a variety of different applications.

Formex GK

Formex™ provides excellent electrical insulation and barrier materials for industrial and consumer electronic equipment. It is most often used in computing servers, storage devices, electrical distribution equipment, power supplies, medical devices and HVAC equipment. Formex™ can score-and-fold without cracking. It is recognized in the marketplace for superior dielectric performance compared to other materials. It has chemical resistance and is non-hygroscopic (which means lacking the property of absorbing and retaining an appreciable quantity of moisture from the air) for better stability and performance. Formex™ (rated UL94 V-0) polypropylene flame retardant materials provide superior electrical insulation in industrial and consumer electronic equipment. It is also useful as a thermal and electrical barrier material.


Statex™ is a resilient static dissipative material that serves as an electrical barrier to both insulate and protect electronic components from electrostatic discharge. Statex™ does not generate static like other competing electrical insulation materials. If Statex™ comes in contact with a static electrical charge; it safely dissipates the charge across the surface of the material to a ground. Computer manufacturers often use static dissipative materials to insulate and protect their circuit boards. As a highly effective electrical barrier and static dissipative material, Statex™ is an ideal product for design engineers to use to keep circuit boards from developing static electricity between each other and from experiencing electrostatic shock from outside sources.


Ragtex® is a dense, rigid material produced in multi-ply construction from a blend of unbleached kraft pulp and cotton rag fibers. Ragtex® is free of conducting particles, chemical impurities and foreign matter. It has excellent dielectric and mechanical strength with excellent formability. Ragtex® can be used in transformer insulation, barrier insulation, appliances, electrical hardware, and gaskets and slot insulation.


E-FR® is an Underwriter’s Laboratories approved flame retardant board, multi-ply constructed from unbleached kraft pulp. The UL 94 Flammability Classification is 94V-0. E-FR® has good mechanical strength, punch-ability and fold-ability. Custom Gasket Mfg. supplies UL approved flame retardant E-FR®. This material is especially recommended for applications requiring fold lines and creases in material thickness greater than 0.020 in. (0.50mm). E-FR® will not break when folded, unlike fish paper.


Lexan® is the brand name for polycarbonate plastic. It is an excellent thermal insulator. It is perfect for applications that require a strong, impact resistant, glass-like surface. It is a thermoplastic used in many applications that require a large temperature service range, excellent electrical properties, and dimensional stability. Polycarbonate film features qualities such as high durability, design flexibility, and structural integrity. It provides excellent clarity, light transmission and UV stability. Polycarbonate film provides the highest Class CC-1 rating for approved light transmitting plastics under all three major model building codes. Polycarbonate film benefits include UV & impact resistance, excellent clarity and superior electrical properties. Lexan® is a leading polycarbonate offering impact resistance, durability, heat and flame resistance and many other properties. This thermoplastic provides high levels of mechanical, optical and electrical properties. Lexan® is flame retardant and has UL94 V-0 or VTM-O ratings. It is chemical resistant, has excellent dielectric strength and low moisture absorption.

STYLES: LEXAN® FR 60, LEXAN® FR65, LEXAN® FR63, LEXAN® FR66, FR25 LEXAN®, LEXAN® FR83, LEXAN® 8010, LEXAN® 8030, LEXAN® 8040, LEXAN® 9600


Phenolics are a fabricated reinforced laminate produced from a fine weave cotton cloth impregnated with a phenolic resin binder. The fine weave linen yields good mechanical properties, dimensional stability and a better finish for machined components. They are available in sheet stock, rod, angle and U channel forms. G phenolic glass series of phenolics are a broad range of materials for specialized applications of electrical insulation, also known as Garolite®. It is a glass woven fabric impregnated with various resin binders to optimize unique characteristic of the material. It is available in a wide range of colors. G10 FR4® is used in the electrical insulation of appliance PCBs and mechanical lines. G10 FR4® is created from electrical alkali-free glass cloth that has been impregnated with an epoxy resin under pressure and heat. It possesses high mechanical properties at medium humidity and good dielectric stability at high humidity. Custom Gasket Mfg. is able to easily custom machine parts as well as and die-cut parts from sheets to your exact specifications. G10 FR4® has anti-fire properties and is the most versatile laminate available. The material is fabricated from a glass woven cloth impregnated with an epoxy resin binder. The epoxy resin yields a laminate with excellent mechanical and dielectric properties.

Vulcanized Fiber

Washers and gaskets die cut from vulcanized fiber have excellent tear strength, good abrasion resistance and outstanding dielectric properties. This material is often chosen due to a relative lower cost. Vulcanized Fiber is UL recognized and rated UL94 HB.

Please visit our gasket materials page for more information on our extensive selection of materials.

For more information on custom electrical insulators or to speak with one of our knowledgeable professionals, please feel free to Contact Us or complete our online Request For Quote form.

Call 800-985-6750 or email your inquiry to sales@customgasketmfg.com.