Home | Fiberglass Flat Washers - High-Temperature Electrical Insulation Washers

Fiberglass Flat Washers - High-Temperature Electrical Insulation Washers

Fiberglass flat washers provide excellent electrical insulation, high-temperature resistance, and mechanical strength for demanding applications in electrical equipment, aerospace, and industrial machinery. Superior Washer & Gasket Corp manufactures fiberglass washers from G10/FR4 and other glass-reinforced plastic materials in standard and custom sizes.

Our ISO 9001:2015 certified facility produces fiberglass plastic washers alongside phenolic, Kapton, mica, and other high-performance insulating washers-all made in the U.S.A. to your exact dimensional requirements and tolerances.

  • Excellent electrical insulation and high-temperature resistance
  • G10/FR4 and glass-reinforced plastic materials
  • Standard and custom fiberglass washer sizes
  • ISO 9001:2015 certified quality control
  • Made in the U.S.A.

Showing 1–22 of 22 products

SKU ID OD Thickness Material ID TOL OD TOL Quantity

330-223-061

ID 0.171
OD 0.688
Thickness 0.061
Material Fiberglass
ID TOL +-.005
OD TOL +-.005
Quantity

330-224-015

ID 0.098
OD 0.155
Thickness 0.015
Material Fiberglass
ID TOL +-.005
OD TOL +-.005
Quantity

330-226-031

ID 0.313
OD 0.748
Thickness 0.031
Material Fiberglass
ID TOL +-.005
OD TOL +-.005
Quantity

450-10-015

ID 0.094
OD 0.25
Thickness 0.015
Material Fiberglass
ID TOL +-.005
OD TOL +-.005
Quantity

450-11-015

ID 0.122
OD 0.218
Thickness 0.015
Material Fiberglass
ID TOL +-.005
OD TOL +-.005
Quantity

450-12-031

ID 0.125
OD 0.31
Thickness 0.031
Material Fiberglass
ID TOL +-.005
OD TOL +-.005
Quantity

450-13-062

ID 0.125
OD 0.317
Thickness 0.062
Material Fiberglass
ID TOL +-.005
OD TOL +-.005
Quantity

450-14-062

ID 0.125
OD 0.5
Thickness 0.062
Material Fiberglass
ID TOL +-.005
OD TOL +-.005
Quantity

450-15-031

ID 0.142
OD 0.38
Thickness 0.031
Material Fiberglass
ID TOL +-.005
OD TOL +-.005
Quantity

450-16-062

ID 0.178
OD 0.562
Thickness 0.062
Material Fiberglass
ID TOL +-.005
OD TOL +-.005
Quantity

450-17-062

ID 0.203
OD 0.443
Thickness 0.062
Material Fiberglass
ID TOL +-.005
OD TOL +-.005
Quantity

450-18-031

ID 0.25
OD 0.5
Thickness 0.031
Material Fiberglass
ID TOL +-.005
OD TOL +-.005
Quantity

450-19-062

ID 0.312
OD 0.562
Thickness 0.062
Material Fiberglass
ID TOL +-.005
OD TOL +-.005
Quantity

450-20-062

ID 0.38
OD 0.75
Thickness 0.062
Material Fiberglass
ID TOL +-.005
OD TOL +-.005
Quantity

450-21-062

ID 0.515
OD 0.88
Thickness 0.062
Material Fiberglass
ID TOL +-.005
OD TOL +-.005
Quantity

450-22-093

ID 0.64
OD 1.193
Thickness 0.093
Material Fiberglass
ID TOL +-.005
OD TOL +-.005
Quantity

450-23-093

ID 0.765
OD 1.317
Thickness 0.093
Material Fiberglass
ID TOL +-.005
OD TOL +-.005
Quantity

450-24-093

ID 1.015
OD 1.755
Thickness 0.093
Material Fiberglass
ID TOL +-.005
OD TOL +-.005
Quantity

450-25-125

ID 0.25
OD 2.0
Thickness 0.125
Material Fiberglass
ID TOL +-.005
OD TOL +-.005
Quantity

450-26-125

ID 0.375
OD 2.0
Thickness 0.125
Material Fiberglass
ID TOL +-.005
OD TOL +-.005
Quantity

450-27-125

ID 0.5
OD 2.0
Thickness 0.125
Material Fiberglass
ID TOL +-.005
OD TOL +-.005
Quantity

450-28-125

ID 0.625
OD 2.0
Thickness 0.125
Material Fiberglass
ID TOL +-.005
OD TOL +-.005
Quantity

Fiberglass Flat Washer Frequently Asked Questions

Below are answers to some of the most common questions about fiberglass flat washers.

What are fiberglass flat washers?
Fiberglass flat washers are manufactured from glass fiber reinforced thermoset or thermoplastic composite materials, most commonly G10/FR4 epoxy fiberglass laminate. They offer high strength, excellent electrical insulation, low thermal conductivity, and good chemical resistance, making them well suited for electrical panels, circuit boards, transformers, and high-voltage applications.

What grade of fiberglass are your washers made from?
Superior Washer fiberglass flat washers are manufactured from G10 epoxy fiberglass laminate, the standard grade for general electrical insulation applications. Contact us to discuss your specific application requirements.

What are the main applications for fiberglass washers?
Fiberglass washers are used wherever electrical insulation, thermal resistance, and mechanical strength are required simultaneously. Common applications include electrical panel assemblies, transformer mounting, circuit board construction, battery systems, and any application where metal washers would create an unwanted electrical path.

Can you make custom fiberglass flat washers?
Yes. Superior Washer manufactures custom fiberglass washers to your exact OD, ID, and thickness specifications in G10 fiberglass laminate. Contact us via the Quick Quote form.

Are your fiberglass flat washers made in the USA?
Yes. All fiberglass flat washers are manufactured in the United States under our ISO 9001:2015 certified Quality Management System. Material certifications are available upon request.

Need something other than fiberglass? Our full catalog includes metal and non-metal flat washers in a wide variety of materials. Take a look at the complete flat washers lineup to find what you need.