C vs FR-2
Composite · grade comparison
C and FR-2 are both composite grades. FR-2 is the stronger of the two: tensile strength 92 MPa (13.3 ksi) against 76 MPa (11 ksi) for C, about 21% more. In exchange, C is the more ductile: elongation 1.5% versus 1.1% for FR-2. C is lighter (1.36 g/cm³ vs 1.55 g/cm³ for FR-2) and FR-2 is stiffer (7.5 GPa vs 7 GPa). On the shop floor, FR-2 sits in a lower cost tier (standard, $$) than C (premium, $$$).
CChoose it when the part is bent, formed or impact-loaded, or when weight is the constraint.
FR-2Choose it when strength drives the design, or when cost is the deciding factor.
C vs FR-2: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all composite 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 composite 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
Shear Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Elongation at Break
Compressive Strength
Compressive Modulus
Flexural Strength
Flexural Modulus
Izod Impact, Notched
Fracture Toughness (K_IC)
Same in both: Shear Strength 90 MPa13.1 ksi · Hardness, Rockwell M 105 HRM
Physical
Density and transition temperatures.
Density
Glass Transition (Tg)
Water Absorption (24 h)
Water Absorption (Saturation)
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Min Service Temperature
Max Service Temperature (short-term)
Heat Deflection Temp. @ 1.8 MPa
Same in both: Limiting Oxygen Index 30%
Electrical
Conductivity and insulation.
Dielectric Strength
Dielectric Constant (1 MHz)
Dissipation Factor (1 MHz)
Surface Resistivity
Comparative Tracking Index (CTI)
Same in both: Electrical Resistivity 1×10⁹ Ω·m3.94×10¹⁶ µΩ·in · Volume Resistivity 1×10¹¹ Ω·cm
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
UV / Weathering Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Polishability
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Typical Recycled Content
Same in both: Embodied Carbon (primary production) 4.5 kg CO₂/kg · Embodied Water 250 L/kg30 gal/lb
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Same in both: Thermal Diffusivity 0.2 mm²/s · Thermal Shock Resistance Index 0
Strength versus weight
Yield strength against density for every composite grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Manufacturing and finishing
| Capability | C | FR-2 |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$ Premium | $$ Standard |
| Min. machined wall | — | — |
| Best machined surface | — | — |
C vs FR-2 — frequently asked
Is FR-2 stronger than C?
Yes. FR-2 has a typical tensile strength of 92 MPa (13.3 ksi) against 76 MPa (11 ksi) for C — about 21% more.
Which is cheaper, C or FR-2?
FR-2 is the lower-cost material: it sits in the standard tier ($$) while C is premium ($$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
Which is easier to machine, C or FR-2?
FR-2, by a small margin. Both rate very good for machinability — 75/100 against 70/100 for C.
Ready to make it?
Upload a CAD file and FabDigit prices the part in C and FR-2 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.