Quick Answer
G10 material is a NEMA-grade epoxy fiberglass laminate: woven glass cloth bonded with epoxy resin under heat and pressure. It is a strong, dimensionally stable electrical insulator used for washers, spacers, machined parts, and structural insulation. FR4 is the flame-retardant version of G10; G11 and FR5 are the high-temperature versions. IncomePultrusion machines custom parts from certified G10/FR4/G11/FR5 laminate — send your drawing for a 24-hour quote.
What Is G10 Material?
G10 is a high-pressure thermoset laminate made from continuous woven E-glass fabric impregnated with an epoxy resin system. The cloth layers are stacked and cured under heat and pressure into rigid sheets, rods, and tubes. The result combines the tensile strength of glass fiber with the chemical and electrical resistance of epoxy — which is why G10 has been a default electrical-grade laminate for decades.
A few naming facts that save procurement time:
- Garolite is not a different material — it is a long-standing trade name for the same G10-family glass-epoxy laminate.
- “G10 knife scales / handle material” is the consumer knife-making use of the same laminate. It dominates image search but has nothing to do with industrial supply — industrial buyers should specify NEMA grade, thickness, and datasheet requirements instead.
- FR10 and FR11 are not NEMA grades. Requests under these names almost always mean FR4/G10 (standard) or G11/FR5 (high temperature). Confirm the actual temperature and flame requirements before ordering.
The Grade Family: G10, FR4, G11, FR5
All four grades share the same woven-glass reinforcement. They differ in resin system and flame retardancy — choose by operating temperature and whether a flame rating is specified:
| Grade | Resin System | Flame Retardant | Typical Continuous-Use Temperature | Notes |
|---|---|---|---|---|
| G10 | Standard epoxy | No (≈ UL94 HB) | ~130 °C (266 °F), Class B | General-purpose electrical grade |
| FR4 | Standard epoxy + brominated FR | Yes (UL94 V-0 class) | ~130 °C (266 °F), Class B | = flame-retardant G10; most-specified grade worldwide |
| G11 | High-Tg epoxy | No | ~155–180 °C (307–356 °F) | Retains properties at elevated temperature |
| FR5 | High-Tg epoxy + flame retardant | Yes | ~155 °C (311 °F) | = flame-retardant G11; also called FR4 High Tg |
For a focused side-by-side of the two most common grades, see FR4 vs G10: which epoxy fiberglass for washers and parts. For electrical property details, see G10 and FR4 properties for electrical parts.
G10 Material Properties (Typical Values)
Values below are typical published ranges for standard-grade laminate. Actual values vary by manufacturer, thickness, and test direction — always confirm against the datasheet for the specific batch:
| Property | Typical Value (G10/FR4) | Why It Matters |
|---|---|---|
| Dielectric strength | ~500 V/mil (perpendicular, short-time) | Sizing insulation distance in electrical assemblies |
| Tensile strength | ~40,000–50,000 psi | Load-bearing washers, spacers, structural parts |
| Flexural strength | ~60,000–70,000 psi | Resistance to bending under bolt load |
| Water absorption | ~0.10–0.15% (24 h) | Dimensional stability in humid environments |
| Continuous-use temperature | ~130 °C (G10/FR4); 155–180 °C (G11/FR5) | Grade selection for hot assemblies |
| Flame rating | FR4/FR5: UL94 V-0 class; G10/G11: not flame rated | Electrical and fire code compliance |
For code-governed applications, request the FR4 material datasheet for the exact sheet lot with your quote — thickness-specific values (including FR4 material thickness tolerances) are listed there.
Standards and Equivalents: NEMA, IEC EPGC, China 3240
The same material family appears under different standard systems. When a drawing or PO references an unfamiliar designation, this cross-reference covers the common cases:
| NEMA Grade | IEC 60893 Equivalent | Chinese GB Equivalent | Description |
|---|---|---|---|
| G10 | EPGC 201 | 3240 (general class) | Epoxy glass cloth laminate, general purpose |
| FR4 | EPGC 202 | 3240-F / FR-4 class | Flame-retardant epoxy glass laminate |
| G11 | EPGC 203 | 3241 / high-Tg class | High-temperature epoxy glass laminate |
| FR5 | EPGC 204 | High-Tg flame-retardant class | High-temperature + flame retardant |
Equivalents are approximate: each standard sets its own test methods and minimums. For compliance-critical parts, state the governing standard on the PO and request matching certification from the laminate mill.
“FR10” and “FR11” — What Buyers Actually Mean
NEMA never defined FR10 or FR11 glass-epoxy laminate grades. In inbound inquiries these names appear frequently, and in practice they map to:
- “FR10” → almost always a mix-up of FR4 / G10 (occasionally unrelated materials such as Panasonic R-FR10 PCB substrate or DuPont PA6-FR10 flame-retardant nylon).
- “FR11” → almost always the high-temperature grades G11 or FR5.
If your specification mentions either name, send the operating temperature and flame-rating requirement — we will confirm the correct NEMA grade with a datasheet before machining, so the parts match the intent rather than the typo.
Machining G10 Material
G10/FR4 machines cleanly with carbide or diamond tooling; the abrasive glass content wears high-speed steel quickly. CNC routing and milling handle flat parts and profiles; punching is economical for high volumes of simple shapes in thinner sheet; drilling with backup plates prevents exit-face breakout. Edges are deburred after machining to remove loose fibers.
Detailed tooling, feed, and tolerance guidance is in CNC machining G10 and FR4 parts. For machining G10 material to drawing, send the part file — prototypes can be validated before production quantities.
Forms: Sheet, Rod, Tube — and What We Supply
The G10/FR4 laminate family is produced as sheet, rod, and tube. To be transparent about our scope: we do not sell laminate sheets. IncomePultrusion purchases certified NEMA-grade laminate from qualified mills and CNC-machines it into finished parts — washers, spacers, shoulder washers, sleeves, and custom profiles. This means:
- G10 sheet buyers: source sheet from a laminate distributor; if you need finished parts instead of raw sheet, that is exactly what we machine.
- G10 rod: see our epoxy glass composite rod product page.
- Tube and CNC parts: G10 & FR4 tube for hollow insulators and bushings, plus custom G10 & FR4 machined parts quoted per drawing.
- Washers and machined parts: custom insulating washers hub and G10 & FR4 washers page.
Typical Applications
- Electrical insulation: washers, terminal boards, busbar supports, switchgear and panel insulation
- Galvanic isolation: breaking metal-to-metal paths between dissimilar metals in outdoor and marine assemblies
- High-temperature fixtures: G11/FR5 parts near motors, transformers, and power electronics
- Precision spacers and standoffs: dimensionally stable spacing in instrument and chassis assemblies
Frequently Asked Questions
What is G10 material made of?
Woven E-glass fabric impregnated with epoxy resin, cured under heat and pressure into a rigid thermoset laminate. It is sold as sheet, rod, and tube, and machined into finished parts.
Is G10 the same as FR4?
They are the same base laminate family. FR4 adds brominated flame-retardant chemistry and meets the NEMA FR4 grade (UL94 V-0 class); G10 is the general-purpose, non-flame-rated grade. Mechanically and electrically they are very similar in dry conditions. Details: FR4 vs G10 comparison.
Is G10 electrically conductive?
No. G10 is an electrical insulator with typical dielectric strength around 500 V/mil. Surface contamination or moisture reduces insulating performance, so sealed or clean assemblies are recommended for high-voltage use.
What is the maximum continuous temperature for G10?
About 130 °C (266 °F) for standard G10/FR4. For hotter service use the high-Tg grades: G11 (155–180 °C class) or FR5 when flame retardancy is also required.
Is G10 flame retardant / UL94 V-0?
Standard G10 is not flame rated (roughly UL94 HB behavior). If a flame rating is specified, order FR4 (V-0 class) or FR5 for high-temperature applications.
What is the difference between G10 and G11?
The resin system. G11 uses a high-Tg epoxy that retains mechanical and electrical properties at higher temperature (155–180 °C class) than G10’s ~130 °C. Room-temperature strength is comparable — G11 is about heat resistance, not extra strength.
Is Garolite the same as G10?
Garolite is a trade name for the same glass-epoxy laminate family that includes G10. For critical applications, compare datasheets rather than relying on the name.
What are the Chinese 3240 and IEC EPGC equivalents of G10/FR4?
Common cross-references: G10 ≈ EPGC 201 ≈ 3240; FR4 ≈ EPGC 202; G11 ≈ EPGC 203; FR5 ≈ EPGC 204. Equivalents are approximate — state the governing standard on the PO for compliance parts.
Can G10 be CNC machined?
Yes — routing, milling, drilling, and punching are all standard. Use carbide or diamond tooling because the glass content is abrasive. See our G10/FR4 CNC machining guide.
Do you sell G10 sheets?
No. We machine finished parts from certified NEMA-grade laminate sourced from qualified mills. If you need washers, spacers, or custom profiles to drawing, that is our scope — request a quote below.
Need Parts Machined from G10/FR4 Laminate?
Send your drawing, grade requirement (G10, FR4, G11, or FR5), and quantity through the quote request page — a quotation with material datasheet support is returned within 24 hours. For washer and spacer sizing, start at the custom insulating washers hub.