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Material Information

Phenolics are thermoset resins formed by the polymerization of phenol and formaldehyde, which can then be impregnated with cotton canvas or linen, paper, or glass cloth materials to form industrial laminates. Overall, industrial laminates are dense, strong and durable, moisture resistant, lightweight, and will not soften when heat is reapplied. Typically they have high mechanical and insulating properties. G-7 is made up of a mixture of silicone resin and glass cloth. G-7 has excellent heat and arc resistance, is self-extinguishing, and has good electrical properties in wet conditions that are even better under dry conditions. It is also the most temperature resistant grade. Although it is not stronger than epoxies and industrial thermosets at lower temperatures, it is stronger at temperatures over 400ºF. These properties make G-7 ideal for use in electrical grade insulation, heating insulation and appliance insulation. G-7 is available in sheet, rod, and tube. G-7 meets MIL-I-24768/17 TYPE GSG


  • High temperature electrical applications
  • High heat insulators
  • Gaskets
  • Armature barriers
  • Mechanical insulators


  • Good wet electrical properties, excellent dry electrical properties
  • Excellent heat and arc resistance
  • Self-extinguishing
  • Desnse and structurally strong
  • Lightweight
  • Doesn’t soften under reapplication of heat


PhysicalAstm Test MethodG-5/G-9G-7G-10/FR-4G-11
Density (lb/in^3)D7920.0670.0650.0650.065
Specific GravityD7921.851.81.81.8
Water Absorption @ 24 hours (%)D5700.
Tensile Strength (PSI) Lengthwise, CrosswiseD63861,600 and 51,10020,000 and –45,000 and 38,00043,000 and 37,000
Flexural Strength (PSI) Lengthwise, CrosswiseD79061,600 and 51,10030000 and –75,000 and 65,00080,000 and 70,000
Compressive Strength (PSI)D69565,00050,00065,00063,000
Flexural Modulus (KPSI) Lengthwise, CrosswiseD7902,000 and 1,7001,600 and –2,700 and 2,4003,000 and 2,700
Izod Impact (Notched), ft-lb/in Lengthwise, CrosswiseD25612.5 and 8.513.0 and –14.0 and 12.012.0 and 9.0
Rockwell HardnessD785M115M105M110M112
Coefficient of Thermal Expansion,
10^-5/°F Lengthwise, Crosswise
D696.83 and 1.00.72 and .90.55 and .66.72 and .83
Continous Service Temp (Operating), °F285430284329
Thermal Conductivity, BTU-in/hr-ft² °FC1772222
Flammability RatingUL94VOVOVOHB
Dielectric Strength, Short Term,
(Volts/Mil) @ .125″ Thick
Arc Resistance (sec)D495180240100120
Dielectric Constant at 1 MHzD1506.34.554.5
Dissipation Factor at 1 MHzD1500.0190.0180.0190.02

Disclosure: The information contained herein are typical values intended for reference and comparison purposes only. They should NOT be used as a basis for design specifications or quality control. Contact us for manufacturers’ complete material property datasheets. All values at 73°F (23°C) unless otherwise noted.


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