Glass Polyester (GPO-1, GPO-2,GPO-3)

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Glass Polyester Characteristics

Glass polyester is a glass-mat reinforced polyester suitable for many applications. We offer it in three styles.

GPO-1 is a cost-effective, general purpose laminate.  It is a solid choice for applications in which good electrical properties, good physical strength and moderate heat resistance are required.

GPO-2 is the laminate of choice when arc- or flame-resistance is required. It has good electrical and physical properties and heat resistance.

GPO-3 is the laminate to choose when arc, flame and carbon track-resistance are needed. GPO-3 offers good physical strength and moderate heat resistance. It is used extensively in the making of electrical components.

Characteristics of glass polyesters include:

  • Economical general purpose laminate (GPO-1)
  • here to help 200Good electrical properties (GPO-1, 2 & 3)
  • Excellent structural properties (GPO-1, 2 & 3)
  • Flame-resistant (GPO-2 & 3)
  • UL-recognized laminate GPO-2 & 3)
  • Arc- and track-resistant (GPO-3)

See the chart below for more details on glass polyester properties.

Applications for Glass Polyester Thermosets

  • High amperage mounting panels (GPO-2)
  • Switch bases (GPO-2)
  • Terminal strips (GPO-2)
  • Arc shoot components (GPO-2)
  • Phase and end barriers (GPO-3)
  • Insulating and bus bar supports (GPO-3)
  • Mounting panels in switchgear and other types of electrical apparatus (GPO-3)

Contact a Dielectric Manufacturing knowledge expert to discuss the use of glass polyesters for fabrication of your parts. Call 800-367-9122 or email

We also are a distributor of glass polyester materials. Contact us about fulfilling your material needs and to get a quote.

Glass Polyester Material Properties

Density1.7e3 - 2.5e3kg/m^3 USD/kg0.0614 - 0.0903lb/in^3 USD/lb
Yield Strength3.66e7 - 4.04e7Pa5.3 - 5.86ksi
Tensile Strength2.5e7 - 5.5e7Pa3.63 - 7.98ksi
Hardness (Vickers)1.35e8 - 1.49e8Pa13.8 - 15.2HV
Impact Strength (notched)4e3 - 3e4J/m^21.9 - 14.3ft.lbf/in^2
Fracture Toughness1.41e6 - 2.69e6Pa/m^0.51.28 - 2.45ksi/in^0.5
Young's Modulus9e9 - 1.44e10Pa1.31 - 2.0910^6 psi
Max Service Temperature151 - 168°C304 - 334°F
Insulator or ConductorInsulatorInsulator
Specific Heat Capability1.09e3 - 1.42e3J/kg °C0.26 - 0.34BTU/lb. °F
Thermal Expansion Coefficient2.00E-05strain/°C11.1µstrain/°F
CO2 Footprint7.59 - 8.38kg/kg7.59 - 8.38lb/lb

Dielectric Manufacturing, Richfield, Wisconsin USA

Glass Polyester Material Properties Provided By Dielectric Manufacturing, Richfield, Wisconsin

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