G-10 Glass Epoxy Washer
Product Description
Product Detail
G-10 Glass Epoxy Washers for Galvanic Corrosion Isolation on Flanged Joints — OEM and Wholesale Supply
G-10 glass epoxy washers are cut from a continuous woven glass fabric laminated with epoxy resin — a dielectric material specified wherever two dissimilar metals must be bolted together without creating an electrical path between them. The washer sits under the nut (and typically under the bolt head) and, together with an insulating sleeve in the bolt hole and an insulating gasket at the flange face, completes the electrical isolation of the joint.
Compared with phenolic and other composite insulating materials, G-10 offers the highest combination of mechanical strength and electrical insulation in a thin section. It also has very low water absorption, which keeps dielectric strength stable across wide ranges of temperature and humidity — a key requirement on outdoor and marine joints where moisture-driven degradation would otherwise break the isolation.
What G-10 Glass Epoxy Is and Why It Is Used
G-10 is a composite material made from continuous woven glass fabric impregnated with an epoxy resin system, then cured under heat and pressure into a rigid laminate. The result is a dense, dimensionally stable sheet that behaves like a structural material while retaining the electrical insulation and moisture resistance of a dielectric laminate.
That combination is what makes G-10 the material of choice for the bolting insulation components in a flange isolation kit. In a fully insulated flanged joint there are three insulating elements — the gasket at the flange face, the sleeve through the bolt hole, and the washer under the nut — and each one must hold its mechanical and dielectric properties under bolt load, temperature cycling and moisture exposure over the life of the line.
What G-10 brings to a flange insulation kit
- High mechanical strength. Withstands bolt torque loads without crushing or extruding, keeping the isolation layer intact when the flange is torqued to specification.
- Low water absorption. Retains dielectric strength in wet, humid and marine service — a failure mode that degrades phenolic washers on extended outdoor exposure.
- Superior electrical characteristics. Dielectric strength and dissipation factor are stable across wide temperature and humidity ranges, giving predictable isolation performance.
- Wide temperature range. Performs within the standard industrial pipeline service envelope, from low ambient through typical process temperatures.
- Long service life. Does not creep or fatigue under continuous bolt load, so isolation is maintained without re-torquing or replacement.
Where G-10 Washers Are Used in the Insulation System
The G-10 washer is one of three dielectric components in a flange insulation kit. Isolating a flanged joint requires breaking every current path through the connection — the gasket breaks the face-to-face path, the sleeve breaks the hole-to-bolt path, and the washers break the nut-to-flange and bolt-head-to-flange paths. Remove any one of the three and the whole isolation system fails.
Component 01
Insulating GasketThe primary dielectric barrier at the flange face. Type D, E or F geometry depending on the flange standard.
Component 02
Insulating SleeveFits through each bolt hole. Prevents the bolt shank from contacting either flange plate.
Component 03
Insulating Washer — G-10Fitted under each nut and under each bolt head. Sized to the fastener diameter and to the required dielectric thickness for the joint.
Component 04
Additional IsolatorsWhere required by the specification: flat washers, secondary washers or combination sets supplied as a matched kit.
Technical Data — G-10 Glass Epoxy Laminate
| Property | Typical Value | Notes |
|---|---|---|
| Composition | Continuous woven glass fabric + epoxy resin | Cured laminate, not a moulded composite |
| Colour | Light green / yellowish green | Standard G-10 laminate colour |
| Water Absorption | Low — typically below 0.15% | Stable dielectric performance in wet or humid service |
| Dielectric Strength | High — consistent across temperature and humidity | Key property for isolation washers |
| Dissipation Factor | Low | Minimises signal loss in sensitive circuits |
| Mechanical Strength | Extremely high for a dielectric laminate | Withstands bolt torque without crushing |
| Service Temperature | Within standard industrial pipeline range | Confirm specific limit against your application |
| Available Formats | Standard bolt sizes / cut to drawing | OD and ID to customer specification |
Exact values vary by thickness and batch. If your specification calls for a fixed limit on water absorption, dielectric strength or temperature, request a batch certificate at the quotation stage.
Typical B2B Applications
Ordering G-10 Glass Epoxy Washers
Washers are supplied either as standard bolt-size stock items or cut to your specific inside diameter, outside diameter and thickness. Send the following details and Kaxite will return a quotation — typically within one working day for standard sizes.
G-10 Glass Epoxy Washers — FAQ
What is G-10 glass epoxy made from?
What is the difference between G-10 and G-11 glass epoxy?
How do G-10 washers fit into a flange insulation kit?
Can G-10 washers be cut to custom sizes?
Why choose G-10 over phenolic for the insulation washers?
What quantity is required to receive OEM pricing?
What is the lead time for G-10 washer orders?
Can G-10 washers be supplied together with sleeves and gaskets?
Request a G-10 Glass Epoxy Washer Quotation
Send the bolt diameter, washer OD, thickness and quantity — or the flange standard and size for a complete kit quotation. Kaxite supplies G-10 washers for OEM flange insulation kits, maintenance replacement and standalone electrical insulation applications.