G11
ASTM D709, D709 Grade G-11 · EN 60893 EP GC 302 · also High Temp Glass Epoxy
G11 is a woven glass-fabric epoxy NEMA laminate (ASTM D709 Grade G-11, EN 60893 EP GC 302, also sold as 3240 high-Tg board) built on a higher-temperature epoxy than G-10.
Values for the Epoxy Matrix condition
G11 grades and fills
G11 is supplied in 2 conditions, soft to hard. Epoxy Matrix is the default FabDigit quotes; the values on this page are for it.
Compare all 2 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
flame-retardant high-temperature glass/epoxy laminate (UL 94 V-0) | Pick when the same high-temperature G-11 mechanical/electrical performance must also carry a UL 94 V-0 flame rating (electrical enclosures, PCB substrates, rail/aerospace interiors). | 330 | |||
Epoxy MatrixDefault standard high-temperature epoxy / woven E-glass laminate (NEMA G-11) | Default choice for high-temperature structural or electrical insulation parts where no flame rating is required. | 340 | 1.8 | 88 Shore D |
What is G11?
G11 is a woven glass-fabric epoxy NEMA laminate (ASTM D709 Grade G-11, EN 60893 EP GC 302, also sold as 3240 high-Tg board) built on a higher-temperature epoxy than G-10. It holds about 340 MPa tensile strength and retains its mechanical and dielectric properties in service up to 180 °C, and is stocked as flat sheet, rod and tube for machined insulation. As a thermoset it cannot be formed, welded or plated, and the glass reinforcement makes machining abrasive and dusty. Choose G-10/FR-4 where roughly 130 °C is sufficient, or the FR5 version when flame retardance is specified. G11 has a density of 1.85 g/cm³ (0.0668 lb/in³), heavier than 67% of composite grades. Its glass-transition temperature is 150°C (302 °F). G11 has a tensile strength of 340 MPa (49.3 ksi), stronger than 61% of composite grades. Elongation at break is 1.8% and the elastic modulus is 22 GPa (3.19 Msi).
What is G11 used for?
- Transformer and coil insulation parts
- Terminal boards and standoffs
- High-temperature PCB substrates (FR5)
- Aerospace electrical insulation
- Motor slot wedges and coil supports
- Switchgear insulating panels
- Structural spacers in cryogenic and vacuum equipment
Advantages
- Low moisture uptake — 0.1%, better than 85% of composite grades
- Tough — resists crack growth — 20 MPa·√m (18.2 ksi·√in), better than 76% of composite grades
G11 properties
Typical room-temperature values for G11-Epoxy Matrix; bars are the position among composite grades.
Physical4
G11 has a density of 1.85 g/cm³ (0.0668 lb/in³), heavier than 67% of composite grades. Its glass-transition temperature is 150°C (302 °F).
Mechanical14
G11 has a tensile strength of 340 MPa (49.3 ksi), stronger than 61% of composite grades. Elongation at break is 1.8% and the elastic modulus is 22 GPa (3.19 Msi).
Thermal9
G11 is rated for continuous service to 180°C (356 °F). It conducts heat at 0.33 W/m·K (0.191 BTU/hr·ft·°F), worse than 53% of composite grades. Thermal expansion is 14 µm/m·K (7.78 µin/in·°F).
Electrical7
G11 is an electrical insulator with a dielectric strength of 16 kV/mm (406.4 V/mil) and a resistivity of 1×10¹² Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (88/100), better than 77% of composite grades. UV resistance is fair.
Sustainability4
Producing a kilogram of G11 takes about 110 MJ of energy and emits 7 kg of CO₂ — less than 60% of composite grades. Typical recycled content is 0%.
Manufacturability4
G11's machinability is fair (45/100, better than 63% of composite grades); weldability not recommended (0/100); formability not recommended (3/100).
Common Calculations4
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the composite family
Yield strength against density for every composite grade FabDigit runs. G11 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with G11
Is G11 easy to machine?
Machine dry with sharp carbide or PCD tooling, high speed / moderate feed, backup plates to stop edge delamination; glass dust is abrasive and requires extraction and respiratory protection.
Can G11 be welded?
Not weldable — thermoset laminate; join by bolting with washers/oversized holes or by epoxy/structural adhesive bonding of abraded, solvent-cleaned surfaces.
Can G11 be formed, bent or molded?
Supplied as flat sheet, rod and tube only; no post-forming — parts must be machined or laminated to shape during the original press cure.
Manufacturability
The process limits FabDigit's quote engine applies to G11. Design inside these and the part quotes instantly; outside them it routes to an engineer.
CNC machining
| Machinability | Better45 / 100 |
|---|---|
| Cutting speed (rough / finish) | — / — |
| Minimum wall | — |
| Minimum internal radius | — |
| Drill depth limit | |
| Best surface (machined / polished) | Ra — / — |
| Hardenable after machining | — |
Sheet metal
| Formability | Not Recommend3 / 100 |
|---|---|
| Weldability | Not Recommend0 / 100 |
G11 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| E-glass woven fabriccontinuous filament woven glass cloth, typically style 7628/7629 or heavier | 55 – 68 | 62 |
| epoxy resin (high-temperature cure systemultifunctional/anhydride- or dicy-cured epoxy for elevated-temperature strength retention | ≥ 32 (balance) |
What surface finishes work on G11?
Cannot be plated or anodized; edges are sanded and can be sealed with epoxy or polyurethane varnish for moisture and UV protection, screen printing and painting need abrasion plus adhesion primer.
Surface treatments FabDigit runs on composite parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Equivalent designations
Standards and trade names that resolve to G11 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- D709D709 Grade G-11
- EN / DIN / Werkstoff-Nr.
- 60893 EP GC 302
- Trade names
- High Temp Glass Epoxy
- Also called
- NEMA G-11
How much does G11 cost?
G11 is a premium-cost composite ($$$), pricier than about 58% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
G11 — frequently asked
What is G11 used for?
G11 is typically used for transformer and coil insulation parts, terminal boards and standoffs, high-temperature PCB substrates (FR5), aerospace electrical insulation, motor slot wedges and coil supports and switchgear insulating panels. In short: high-temp electrical laminate.
What is the tensile strength of G11?
G11 has a typical tensile strength of 340 MPa (49.3 ksi) — stronger than 61% of composite grades. Strength varies by condition: see the 2 listed tempers.
Is G11 easy to machine?
Reasonably — machinability is rated fair (45/100, better than 63% of composite grades). Machine dry with sharp carbide or PCD tooling, high speed / moderate feed, backup plates to stop edge delamination; glass dust is abrasive and requires extraction and respiratory protection.
Can G11 be welded?
Not readily — weldability is rated not recommended (0/100). Not weldable — thermoset laminate; join by bolting with washers/oversized holes or by epoxy/structural adhesive bonding of abraded, solvent-cleaned surfaces.
What surface finishes work on G11?
Cannot be plated or anodized; edges are sanded and can be sealed with epoxy or polyurethane varnish for moisture and UV protection, screen printing and painting need abrasion plus adhesion primer.
Can G11 be formed, bent or molded?
Supplied as flat sheet, rod and tube only; no post-forming — parts must be machined or laminated to shape during the original press cure.
What is the maximum service temperature of G11?
G11 is rated for continuous use to about 180°C (356 °F), and briefly to 220°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does G11 cost?
G11 is a premium-cost composite ($$$), pricier than about 58% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Can FabDigit make parts in G11?
Yes — G11 is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- NEMA LI 1 — Industrial Laminated Thermosetting Products — NEMA (1998)
- ASTM D709 — Standard Specification for Laminated Thermosetting Materials — ASTM (2017)
- MIL-I-24768/3 (GEB) — Plastic Sheet, Laminated, Thermosetting, Glass Cloth, Epoxy Resin — US DoD (1994)
- Engineered Materials Handbook, Vol. 1: Composites — ASM International (1987)
- Garolite / G-11 & FR-5 glass-epoxy laminate datasheets — Professional Plastics / Current Inc. (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.