G10 Applications — Insulators, PCB, Knife Handles & More

G10 material sees use across a broad range of industries wherever reliable electrical insulation, dimensional stability, and mechanical strength are needed simultaneously. The glass-epoxy construction delivers a combination of dielectric strength (~500 V/mil), rigidity, low moisture absorption, and ease of machining that no single alternative fully replicates at G10's price point. This page covers the primary application areas with material requirements for each, and where G10 is and is not the right choice.

At a glance:

• Leading use: electrical insulators, transformer parts, bus bar support
• High-commercial-value niche: knife handles and scales (G10 dominates this market)
• Historical use: PCB substrate — now mostly replaced by FR4 in flame-sensitive assemblies
• Structural role: aerospace isolation mounts, jigs, fixtures, and structural spacers
• High-volume commodity parts: washers, standoffs, terminal boards

Electrical Insulators and Transformer Components

G10's original and largest application domain is high-voltage and medium-voltage electrical insulation. Its dielectric strength of approximately 500 V/mil (short time) and volume resistivity exceeding 10⁹ Ω·cm after standard conditioning make it reliable in power distribution and transformer applications.

Transformer Components

Slot liners, coil spacers, phase barriers, and winding supports for power transformers and distribution equipment are routinely machined or die-cut from G10 sheet. The material's Thermal Class B rating (130°C per IEC 60085) aligns with Class B winding insulation systems used in most standard industrial motors and transformers. Where temperatures exceed 130°C, the G11 or FR5 grades with higher-Tg epoxy systems are specified instead.

Bus Bar Supports and Switchgear

G10 rod, tube, and plate are machined into bus bar standoffs, insulating spacers, and support structures in medium-voltage switchgear panels. The combination of compressive strength (65,000 psi flatwise) and arc resistance (60–120 seconds) makes G10 appropriate for components in close proximity to high-energy arc events, though it is not self-extinguishing — enclosure design and clearances must account for UL94 HB rating.

Terminal Boards and Barriers

Stampable G10 sheet is punched into terminal boards, barrier strips, and connector mounting plates. The punching tolerance is tighter than for paper phenolic, and the cut edges exhibit less fraying.

PCB Substrates

G10 was the original substrate material for printed circuit boards, defined in the late 1960s as a standard industrial laminate under NEMA grade G10. The material provided the dielectric base, dimensional stability for photo-etching fine-line traces, and adequate adhesion for copper foil.

When G10 is appropriate for a PCB application, it provides essentially identical electrical performance to FR4 — the copper clad laminate adhesion, trace etching behavior, and dimensional stability are equivalent. The sole functional difference is the lack of self-extinguishing behavior. Designers working on open-frame industrial controls, outdoor enclosures with fire suppression, or legacy military board replacement should evaluate G10 vs FR4 requirements before specifying. See the G10 vs FR4 comparison.

Knife Handles and Scales

G10 is one of the most widely used handle materials in both production and custom knife manufacturing. Its combination of properties is nearly ideal for this application:

• Dimensional stability in wet environments: G10 absorbs minimal water (0.10% per 24-hr immersion). Unlike wood or micarta, it will not swell or shrink seasonally, keeping the handle tight to the blade tang.
• Chemical resistance: Resistant to sweat, cutting oils, blood, cleaning agents, and mild disinfectants — all encountered in culinary and outdoor use.
• Grip texture: G10 can be textured during machining or grinding (checkered, scalloped, jimped patterns) and holds texture well. The glass fiber gives the finished surface a naturally tactile feel.
• Machinability: G10 shapes easily on CNC mills and grinders. Handle scales can be profiled, beveled, and polished with standard tooling using proper dust collection.
• Color variety: G10 knife handles are available in black, OD green, tan/FDE, red, blue, orange, and custom colors. Color is imparted by pigment in the resin or by colored glass fabric.
• Weight: At 1.85 g/cc, G10 is lighter than most metals used for handle materials while providing far better grip retention than smooth polymers.

G10 competes in the knife handle market primarily with Micarta (linen or canvas phenolic), carbon fiber, various stabilized woods, and thermoplastic elastomers. G10 generally wins on cost, availability, and consistency; it loses to carbon fiber on weight and premium aesthetics, and to Micarta on warmth of feel.

Aerospace Structural Insulators and Components

G10 sees use in aerospace and defense applications under MIL-I-24768/2 (Type GEE) qualification for:

• Electrical isolation mounts: Brackets and standoffs that electrically isolate structural members from each other or from wiring harnesses in aircraft and avionics bays.
• Antenna windows and radomes (limited): G10's dielectric constant of 4.8 and dissipation factor of 0.020 at 1 MHz are workable for some antenna dielectric applications, though lower-loss materials are preferred at microwave frequencies.
• Composite tooling fixtures: G10 is dimensionally stable enough for use as fixture plates, locating templates, and laminate layup cauls in composite manufacturing environments.

The absence of flame retardants in G10 limits its use in interior aircraft components, where FAA 14 CFR Part 25.853 requires materials to meet more stringent burn and smoke-density standards. For those applications, FR4 or approved phenolic laminates are specified.

Washers, Standoffs, and Spacers

High-volume precision parts stamped or machined from G10 sheet include:

• Insulating washers: Flat washers, shoulder washers, and step washers for electrical isolation of fasteners. G10 can be stamped from thin sheet or CNC-turned from rod for tighter tolerances.
• Standoffs: Threaded hex standoffs machined from G10 rod for PCB mounting, enclosure assembly, and electrical isolation applications.
• Spacers and shims: Precision shims machined from thin G10 sheet where both dimensional accuracy and electrical isolation are needed simultaneously.

G10 holds tight tolerances in these forms — machined OD on turned standoffs can be held to ±0.002" without difficulty, and flatwise thickness tolerance on shim stock is typically ±0.005" as-produced.

Structural and Mechanical Components

Beyond electrical applications, G10's stiffness (flexural modulus ~2,500,000 psi) and ease of machining make it useful in purely mechanical roles:

• Jigs and fixtures: Precision fixture plates for assembly tooling where non-conductivity is needed.
• Robotic end-effectors and brackets: Lightweight structural brackets for robot arms where electrical isolation from the robot's conductive structure is required.
• Watercraft components: G10 is occasionally specified for marine interior structural panels and bulkhead components where dimensional stability, non-conductivity, and resistance to bilge chemicals are valued.
• Cryogenic insulation components: G10 maintains useful mechanical properties at cryogenic temperatures (−196°C / liquid nitrogen) and is used in superconducting magnet support structures and cryostat insulation.

Where G10 Is Not Appropriate

G10 is excluded from certain applications by design:

• Applications requiring UL94 V-0: Use FR4 instead. Any application inside a consumer electronics enclosure or where UL/IEC product safety certification is required will fail if G10 is substituted for FR4.
• High-temperature continuous service above 130°C: Use G11, FR5, or silicone-glass G7 laminates rated for higher thermal classes.
• Direct food contact: G10 is not FDA-cleared for direct food contact. See the G10 FDA page.
• Outdoor UV-exposed structural applications: The epoxy matrix yellows and chalks under prolonged UV. Apply protective coating or use UV-stabilized resin systems.

More related guides

Applications

• Electrical Insulators
• Transformer Components
• Structural Insulators
• Washers and Spacers

Industries

• Aerospace
• Electronics
• Knife Making
• Power Generation

Compare to other materials

• G10 vs FR4
• G10 vs Cotton Phenolic

Frequently asked questions — G10 FAQ