G10 · flame-retardant grade
G10-FR4
Properties of the FR4 condition, compared with the other G10 grades.
Pick when a UL 94 V-0 rating or PCB-compatible laminate is required; mechanical properties are essentially G10-like.
What is G10-FR4?
G10-FR4 is G10 in the FR4 grade — pick when a UL 94 V-0 rating or PCB-compatible laminate is required; mechanical properties are essentially G10-like. G10-FR4 has a tensile strength of 300 MPa (43.5 ksi), stronger than 50% of composite grades. Elongation at break is 1.8% and the elastic modulus is 20 GPa (2.9 Msi). G10-FR4 has a density of 1.85 g/cm³ (0.0668 lb/in³), heavier than 65% of composite grades. Its glass-transition temperature is 135°C (275 °F). Epoxy Matrix is the default condition FabDigit quotes; FR4 is available on request or by drawing note.
Limitations
- Hard to polish — 25/100, worse than 76% of composite grades
G10-FR4 properties
Typical room-temperature values for G10-FR4 — 9 properties are specific to this condition; the rest are grade-level values shared by every G10 grade. Each bar shows where the value sits among the composite grades in FabDigit's library — further right is higher.
Physical4
G10-FR4 has a density of 1.85 g/cm³ (0.0668 lb/in³), heavier than 65% of composite grades. Its glass-transition temperature is 135°C (275 °F).
Mechanical13
G10-FR4 has a tensile strength of 300 MPa (43.5 ksi), stronger than 50% of composite grades. Elongation at break is 1.8% and the elastic modulus is 20 GPa (2.9 Msi).
Thermal8
G10-FR4 is rated for continuous service to 130°C (266 °F). It conducts heat at 0.35 W/m·K (0.202 BTU/hr·ft·°F), better than 50% of composite grades. Thermal expansion is 14 µm/m·K (7.78 µin/in·°F).
Electrical7
G10-FR4 is an electrical insulator with a dielectric strength of 20 kV/mm (508 V/mil) and a resistivity of 1×10¹² Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (85/100), better than 65% of composite grades. UV resistance is fair.
Sustainability4
Producing a kilogram of G10-FR4 takes about 110 MJ of energy and emits 7 kg of CO₂ — less than 61% of composite grades. Typical recycled content is 0%.
Manufacturability2
G10-FR4's machinability is fair (45/100, better than 64% of composite grades).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other G10 grades and fills
G10 is also supplied in 4 other conditions. The full side-by-side table is on the G10 overview.
- Epoxy MatrixDefaultDefault choice for structural/insulating machined parts where flame rating is not required and service stays below ~130 °C.310 MPa tensile
- FR4Pick when a UL 94 V-0 rating or PCB-compatible laminate is required; mechanical properties are essentially G10-like.300 MPa tensile
Working with G10-FR4
Is G10 easy to machine?
Very abrasive — use sharp carbide or PCD/diamond tooling, high speed, low feed, climb-mill and back the exit side to prevent delamination; dust extraction and respiratory protection are mandatory.
Can G10 be welded?
Not weldable (thermoset); join by bonding with epoxy/acrylic structural adhesives or by bolting with washers to spread load.
Can G10 be formed, bent or molded?
Supplied fully cured; cannot be thermoformed or post-formed — parts are produced by cutting, milling, drilling, waterjet or laser (laser leaves charring).
What surface finishes work on G10?
Sanding/sealing with epoxy or polyurethane topcoat improves moisture and UV performance; deburr holes and seal cut edges to limit wicking; no plating without special activation.
G10 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 clothcontinuous-filament glass fabric (e.g. 7628/2116 style) | 50 – 65 | 58 |
| epoxy resin (DGEBA + hardener)non-flame-retarded for G10; brominated for FR-4 | ≥ 35 (balance) | — |
G10-FR4 — frequently asked
What is G10-FR4 used for?
G10-FR4 is typically used for electrical insulators and standoffs, knife handles and scales, transformer and coil spacers, switchgear barriers and terminal strips, cryogenic structural supports (G10-CR) and machine guards and non-conductive fixture plates. In short: premium electrical glass laminate.
What is the tensile strength of G10-FR4?
G10-FR4 has a typical tensile strength of 300 MPa (43.5 ksi) — stronger than 50% of composite grades. Strength varies by condition: see the 5 listed tempers.
Is G10-FR4 easy to machine?
Reasonably — machinability is rated fair (45/100, better than 64% of composite grades). Very abrasive — use sharp carbide or PCD/diamond tooling, high speed, low feed, climb-mill and back the exit side to prevent delamination; dust extraction and respiratory protection are mandatory.
Can G10-FR4 be welded?
Not weldable (thermoset); join by bonding with epoxy/acrylic structural adhesives or by bolting with washers to spread load.
What surface finishes work on G10-FR4?
Sanding/sealing with epoxy or polyurethane topcoat improves moisture and UV performance; deburr holes and seal cut edges to limit wicking; no plating without special activation.
Can G10-FR4 be formed, bent or molded?
Supplied fully cured; cannot be thermoformed or post-formed — parts are produced by cutting, milling, drilling, waterjet or laser (laser leaves charring).
What is the maximum service temperature of G10-FR4?
G10-FR4 is rated for continuous use to about 130°C (266 °F), and briefly to 180°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in G10-FR4?
Yes — G10-FR4 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)
- MIL-I-24768/2 (GEE) Plastic Sheet, Laminated, Glass Cloth, Epoxy — U.S. DoD (1994)
- Garolite G10/FR4 laminate datasheets — Professional Plastics / Current Inc. (2023)
- Handbook on Materials for Superconducting Machinery (G-10CR data) — NIST/Battelle (1977)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.