EPDM vs FEPM
Polymer · grade comparison
EPDM and FEPM are both polymer grades. FEPM is the stronger of the two: tensile strength 16 MPa (2.32 ksi) against 12 MPa (1.74 ksi) for EPDM, about 33% more. In exchange, EPDM is the more ductile: elongation 400% versus 250% for FEPM. EPDM is lighter (1.15 g/cm³ vs 1.55 g/cm³ for FEPM) and FEPM is stiffer (0.01 GPa vs 0.01 GPa). On the shop floor, EPDM machines more easily (30 vs 20 out of 100) and EPDM sits in a lower cost tier (standard, $$) than FEPM (high, $$$$).
EPDMChoose it when the part is bent, formed or impact-loaded, or when weight is the constraint.
FEPMChoose it when strength drives the design, or when the part sees heat.
EPDM vs FEPM: 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
Shear Modulus
Bulk Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Elongation at Break
Same in both: Hardness, Shore A 70 Shore A · Hardness, Shore D 22 Shore D · Tear Strength 25 kN/m143 lbf/in · Compression Set (22 h, 70 °C) 20%
Physical
Density and transition temperatures.
Density
Glass Transition (Tg)
Water Absorption (24 h)
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
Limiting Oxygen Index
Max Service Temperature (short-term)
Electrical
Conductivity and insulation.
Electrical Resistivity
Dielectric Strength
Dielectric Constant (1 MHz)
Dissipation Factor (1 MHz)
Volume Resistivity
Comparative Tracking Index (CTI)
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: UV / Weathering Resistance 95 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Formability (cold)
Polishability
Mold Shrinkage
Processing Melt Temperature (typ.)
Same in both: Mold Temperature (typ.) 175°C347 °F
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
Common Calculations
Ratios derived from the values above.
Thermal Shock Resistance Index
Same in both: Specific Strength (UTS / density) 10 kN·m/kg · Specific Stiffness (E / density) 0 MN·m/kg · Thermal Diffusivity 0.1 mm²/s
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.
Manufacturing and finishing
| Capability | EPDM | FEPM |
|---|---|---|
| Injection molding | Yes | — |
| Default condition | Solid | — |
| Relative cost | $$ Standard | $$$$ High |
| Min. machined wall | — | — |
| Best machined surface | — | — |
| Chrome Plating (Plastic) | Yes | — |
| EMI Shielding Coating | Yes | — |
| Soft Touch Coating | Yes | — |
| Spray Painting | Yes | — |
| UV Coating | Yes | — |
EPDM vs FEPM — frequently asked
Is FEPM stronger than EPDM?
Yes. FEPM has a typical tensile strength of 16 MPa (2.32 ksi) against 12 MPa (1.74 ksi) for EPDM — about 33% more.
Which is cheaper, EPDM or FEPM?
EPDM is the lower-cost material: it sits in the standard tier ($$) while FEPM is high ($$$$). 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, EPDM or FEPM?
EPDM, by a small margin. Both rate poor for machinability — 30/100 against 20/100 for FEPM.
Ready to make it?
Upload a CAD file and FabDigit prices the part in EPDM and FEPM 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.