G-11/FR-5 GLASS EPOXY COMPOSITE LAMINATE MATERIAL
G-11 Epoxy Sheets are premium-grade thermoset composite laminates specifically designed for high-temperature electrical insulation and structural applications. Produced by combining multiple layers of woven fiberglass cloth with specially formulated epoxy resin systems, G-11 laminates deliver superior electrical, mechanical, and thermal performance compared to conventional insulation materials.
One of the key advantages of G-11 Epoxy Sheets is their ability to retain excellent dielectric and mechanical properties at elevated operating temperatures. The material exhibits outstanding thermal stability, high compressive strength, excellent arc resistance, and low moisture absorption, making it ideal for critical electrical and industrial applications.
G-11 laminates provide exceptional dimensional stability and resistance to chemicals, oils, and environmental conditions. Their excellent machinability allows manufacturers to fabricate precision components such as electrical insulators, spacers, support plates, terminal boards, busbar supports, washers, and custom-engineered parts.
These sheets are extensively used in electrical power distribution systems, transformers, switchgear assemblies, motor insulation systems, generators, aerospace structures, railway applications, and industrial machinery. Their combination of high-temperature performance and mechanical durability makes them a preferred choice for demanding engineering environments.
Available in various thicknesses and sheet sizes, G-11 Epoxy Sheets provide engineers and manufacturers with a dependable insulation material capable of delivering long-term reliability under severe operating conditions.
What Is G-11 Material?
G-11 FR-5 is a thermosetting industrial fibre glass composite laminate consisting of a continuous filament glass cloth material with an epoxy resin binder. This product, first introduced in the 1950’s, has characteristics of high strength, low moisture absorption, excellent electrical properties and chemical resistance. These properties are maintained not only at room temperature but also under humid or moist conditions. NEMA G11 was the designation given to Glass Epoxy sheet composite by the National Electrical Manufacture Association (NEMA) to specify a consistent product between manufactures.
What Is Micarta G-11 Laminate?
Micarta was the Westinghouse trade name for their Micarta Sheet materials. Micarta materials alone can be any of the several NEMA Industrial laminate grades unless it is specified Micarta G11 Type GEB.
In today’s G11 laminate sheet is made up with a hight temperature epoxy making up the bulk of heavy sheet and then using finer glass cloth with high temperature resistant epoxy giving a high performance outer finish.
Today what is called FR5 is the Brominated flame retardant version of G 11. The FR 5 material can usually be used where G11 material is specified, however G11 Laminate should not be used where FR-5 is specified.
Another variation of G11 fiberglass sheet is G11 CR laminate used in cryogenic applications.
Both G-11 and FR-5 are rated at 300 degree F continuous operating temperature.G11 has a low dielectric loss and has a retention of 50% of mechanical properties at 300 degrees or 150 C. Because of these characteristics, this material should be used in applications where temperatures in excess of 125 degrees C are encountered. Because they are thermosets, no melting will occur with these grades, however charring will be observed after extended periods above this temperature rating. FR-5 has a UL flammability rating of 94 V-0.
G-11 Tube is stocked at Polymer Plastics in limited quantities, but is usually made to order. This process is made using the same epoxy saturated glass cloth as the sheet is made, but wound over mandrels and cured and the OD ground to size.
G-11 Rod is commonly turned, and ground from sheet stock. You can special order Mil Spec grade rolled and molded rod on a custom order basis.
With these outstanding characteristics, it is easy to understand why G-11 and FR-5 materials are such versatile materials and is used in a wide variety of applications.
Properties, Applications and Availabilities for the G-11/FR-5 Glass Epoxy Composite Laminate Sheet and Rod
| Properties | Applications | Availabilities |
|---|---|---|
| High dielectric strength | Electrical equipment | Rod: .062″ to 4.500″ |
| Radiation resistant | Aerospace conditions | Sheet: .005″ to 3.000″ |
| High tensile strength | Rocket cases | Tubing: .187″ I.D. to 6.00″ I.D., wall thickness, 0.62″ to 1.50″ |
| Low cold flow or creep | Antenna insulators | Standard Color: Browinsh-Green. Special order black color |
| Chemically resistant | Test boards | with minimum ordering quantities. |
| High flexural strength | End plates | |
| Dimensional stability | Cryogenic insulation | |
| Low moisture absorption | Solder Frames | |
| Low dissipation factor | Test fixtures | |
| High impact strength | Medical diagnostic | |
| Cryogenic serviceability | Circuit board holders | |
| Terminal boards | ||
| Underwater conditions |
Specifications
| NEMA GRADE |
FED. SPEC. L-L-31 |
MIL | MIL SPEC TYPE |
JAN-P-13 TYPE LTS |
ARMY SPEC. |
ASTM D-709 TYPE |
NAVY SPEC. |
|---|---|---|---|---|---|---|---|
| G-11 | GRADE: N/A | MIL-I-24768/3 | GEB | N/A | N/A | IV | GEB |
| TYPE IV | MIL-P-18177 |
