Epoxy FR4 vs Epoxy GF30
Polymer · Epoxy grade comparison
Epoxy FR4 and Epoxy GF30 are two grades of the same polymer grade, Epoxy: FR4 (FR-4 / G-10) versus GF30 (30 % short glass fiber reinforced epoxy molding compound). The chemistry is identical, so every difference below comes from the condition. Epoxy FR4 is the stronger of the two: tensile strength 310 MPa (45 ksi) against 110 MPa (16 ksi) for Epoxy GF30, about 182% more. Epoxy FR4 is the more ductile: elongation 4% versus 1.5% for Epoxy GF30. Epoxy GF30 is lighter (1.75 g/cm³ vs 1.85 g/cm³ for Epoxy FR4) and Epoxy FR4 is stiffer (22 GPa vs 11 GPa).
Epoxy FR4Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.
Epoxy GF30Choose it when weight is the constraint, or when the part sees heat.
Epoxy FR4 vs Epoxy GF30: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all polymer grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all polymer grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Tensile Strength (Ultimate)
Elongation at Break
Compressive Strength
Flexural Strength
Flexural Modulus
Shear Strength
Izod Impact, Notched
Same in both: Shear Modulus 1.2 GPa0.17 Msi · Bulk Modulus 5 GPa0.65 Msi · Poisson's Ratio 0.35 · Compressive Modulus 3 GPa0.44 Msi · Fracture Toughness (K_IC) 0.6 MPa·√m0.55 ksi·√in · Hardness, Shore D 85 Shore D · Hardness, Rockwell M 100 HRM
Physical
Density and transition temperatures.
Density
Glass Transition (Tg)
Water Absorption (24 h)
Same in both: Water Absorption (Saturation) 1.6% · Refractive Index 1.56 · Light Transmission 88%
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Heat Deflection Temp. @ 1.8 MPa
Same in both: Specific Heat Capacity 1,100 J/kg·K0.26 BTU/lb·°F · Min Service Temperature -50°C-58 °F · Heat Deflection Temp. @ 0.45 MPa 130°C266 °F · Limiting Oxygen Index 20% · Max Service Temperature (short-term) 180°C356 °F
Electrical
Conductivity and insulation.
Dielectric Constant (1 MHz)
Dissipation Factor (1 MHz)
Comparative Tracking Index (CTI)
Same in both: Electrical Resistivity 1×10¹³ Ω·m3.94×10²⁰ µΩ·in · Dielectric Strength 20 kV/mm508 V/mil · Volume Resistivity 1×10¹⁵ Ω·cm · Surface Resistivity 1×10¹⁴ Ω
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Corrosion Resistance 82 / 100 · UV / Weathering Resistance 25 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Mold Shrinkage
Same in both: Weldability 0 / 100 · Formability (cold) 5 / 100 · Polishability 75 / 100 · Mold Temperature (typ.) 165°C329 °F
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 137 MJ/kg58,899 BTU/lb · Embodied Carbon (primary production) 6.6 kg CO₂/kg · Embodied Water 190 L/kg22.8 gal/lb · Typical Recycled Content 0%
Strength versus weight
Yield strength against density for every polymer grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Epoxy FR4 vs Epoxy GF30 — frequently asked
Is Epoxy FR4 stronger than Epoxy GF30?
Yes. Epoxy FR4 has a typical tensile strength of 310 MPa (45 ksi) against 110 MPa (16 ksi) for Epoxy GF30 — about 182% more.
Which grade does FabDigit quote by default, FR4 or GF30?
Specify the condition in the material field or the drawing note; FabDigit prices the quote for the state you call out.
Which is easier to machine, Epoxy FR4 or Epoxy GF30?
Epoxy GF30. Its machinability rates fair (35/100) against poor (30/100) for Epoxy FR4.
Ready to make it?
Upload a CAD file and FabDigit prices the part in Epoxy FR4 and Epoxy GF30 side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.
Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.