3240 FR4
Flame-retardant grade
Choose when UL 94 V-0 / self-extinguishing behaviour is mandatory (electronics, switchgear, PCB substrate).
Values for the FR4 condition
Other 3240 grades and fills
3240 is listed in 4 conditions; see the grade overview at 3240.
Compare all 4 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
ESD / anti-static black epoxy glass laminate | Choose for SMT pallets, ICT/test fixtures and semiconductor handling where static dissipation is required. | — | 275 | 1.7 | 105 HRM |
FR4This page flame-retardant epoxy glass cloth laminate (UL 94 V-0) | Choose when UL 94 V-0 / self-extinguishing behaviour is mandatory (electronics, switchgear, PCB substrate). | — | 290 | — | — |
flame-retardant high-temperature epoxy glass laminate (V-0, Class F/H) | Use when both V-0 flammability and 155–180 °C service are required. | — | 310 | 1.7 | 110 HRM |
Cold rolled | Specify for LN2/LHe and superconducting-magnet structures where low-temperature strength and controlled resin content matter. | — | 415 | 2 | 110 HRM |
What is 3240 FR4?
3240 FR4 is 3240 in the FR4 grade — choose when UL 94 V-0 / self-extinguishing behaviour is mandatory (electronics, switchgear, PCB substrate). 3240 FR4 has a tensile strength of 290 MPa (42.1 ksi), stronger than 53% of composite grades. Elongation at break is 1.8% and the elastic modulus is 21 GPa (3.05 Msi). 3240 FR4 has a density of 1.85 g/cm³ (0.0668 lb/in³), heavier than 67% of composite grades. Its glass-transition temperature is 135°C (275 °F).
3240 FR4 properties
Typical room-temperature values for 3240 FR4; 11 are specific to this condition. Other listed values are 3240 reference data and may not represent this condition. Bars are the position among composite grades.
Physical4
3240 FR4 has a density of 1.85 g/cm³ (0.0668 lb/in³), heavier than 67% of composite grades. Its glass-transition temperature is 135°C (275 °F).
Mechanical12
3240 FR4 has a tensile strength of 290 MPa (42.1 ksi), stronger than 53% of composite grades. Elongation at break is 1.8% and the elastic modulus is 21 GPa (3.05 Msi).
Thermal8
3240 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
3240 FR4 is an electrical insulator with a dielectric strength of 18 kV/mm (457.2 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 3240 FR4 takes about 110 MJ of energy and emits 6.5 kg of CO₂ — less than 60% of composite grades. Typical recycled content is 0%.
Manufacturability2
3240 FR4's machinability is fair (45/100, better than 63% of composite grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 3240 FR4
Is 3240 easy to machine?
Machine with sharp carbide or PCD tooling, high speed / moderate feed, no coolant needed but strong dust extraction is mandatory (respirable glass dust); back up drilled holes to avoid delamination and chip-out.
Can 3240 be welded?
Not weldable — thermoset laminate; join by bolting, riveting or epoxy/acrylic structural adhesive after abrading and solvent-cleaning the surface.
Can 3240 be formed, bent or molded?
Supplied as fully cured flat sheet, rod or tube; no post-forming possible — parts are cut, routed, punched (thin sheet, warm) or waterjet from stock.
What surface finishes work on 3240?
Edges deburr easily; surfaces can be sanded and coated with epoxy or polyurethane paint for UV protection; copper-clad versions accept standard PCB etching and plating processes.
3240 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 clothwoven E-glass reinforcement, 7628/2116-type styles | 50 – 65 | 58 |
| bromine (FR grades only)≈15–20 wt% brominated epoxy gives ~2–4% Br in FR-4/FR-5 | 0 – 4 | 0 |
| pigment / filleryellow, water-green or black colouring; carbon for ESD grades | 0 – 2 | 0.5 |
| epoxy-phenolic resin ( + )DGEBA/phenolic novolac cured system; FR-4 uses brominated epoxy | ≥ 35 (balance) | — |
3240 FR4 — frequently asked
What is 3240 FR4 used for?
3240 FR4 is typically used for structural insulation boards, mechanical/electrical spacers, PCB backing plates and test fixtures. In short: G-10 equivalent epoxy-glass; strongest laminate in family; structural plus electrical grade.
What is the tensile strength of 3240 FR4?
3240 FR4 has a typical tensile strength of 290 MPa (42.1 ksi) — stronger than 53% of composite grades. Strength varies by condition: see the 4 listed tempers.
Is 3240 FR4 easy to machine?
Reasonably — machinability is rated fair (45/100, better than 63% of composite grades). Machine with sharp carbide or PCD tooling, high speed / moderate feed, no coolant needed but strong dust extraction is mandatory (respirable glass dust); back up drilled holes to avoid delamination and chip-out.
Can 3240 FR4 be welded?
Not weldable — thermoset laminate; join by bolting, riveting or epoxy/acrylic structural adhesive after abrading and solvent-cleaning the surface.
What surface finishes work on 3240 FR4?
Edges deburr easily; surfaces can be sanded and coated with epoxy or polyurethane paint for UV protection; copper-clad versions accept standard PCB etching and plating processes.
Can 3240 FR4 be formed, bent or molded?
Supplied as fully cured flat sheet, rod or tube; no post-forming possible — parts are cut, routed, punched (thin sheet, warm) or waterjet from stock.
What is the maximum service temperature of 3240 FR4?
3240 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.
Sources
- GB/T 1303.4 (Epoxy phenolic glass cloth laminated sheet) (2009)
- ASTM D709 Standard Specification for Laminated Thermosetting Materials (Grade G-10, G-11, FR-4, FR-5) — ASTM International (2017)
- NEMA LI 1 Industrial Laminating Thermosetting Products — NEMA (1998)
- Engineered Materials Handbook Vol. 2: Engineering Plastics / Composites — ASM International (1988)
- G-10/FR-4 glass-epoxy laminate technical data — Professional Plastics / (2023)
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.