EPDM vs IR
Polymer · grade comparison
EPDM and IR are both polymer grades. IR is the stronger of the two: tensile strength 22 MPa (3.19 ksi) against 12 MPa (1.74 ksi) for EPDM, about 83% more. IR is the more ductile: elongation 750% versus 400% for EPDM. IR is lighter (0.93 g/cm³ vs 1.15 g/cm³ for EPDM) and EPDM is stiffer (0.01 GPa vs 0 GPa).
EPDMChoose it when the part sees heat.
IRChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.
EPDM vs IR: 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
Tensile Strength (Ultimate)
Elongation at Break
Hardness, Shore A
Hardness, Shore D
Tear Strength
Compression Set (22 h, 70 °C)
Same in both: Bulk Modulus 2 GPa0.29 Msi · Poisson's Ratio 0.5
Physical
Density and transition temperatures.
Density
Glass Transition (Tg)
Water Absorption (24 h)
Refractive Index
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
UV / Weathering Resistance
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.)
Mold Temperature (typ.)
Sustainability
Primary-production footprint per kilogram.
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
Same in both: Embodied Energy (primary production) 95 MJ/kg40,843 BTU/lb
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Thermal Shock Resistance Index
Same in both: 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 | IR |
|---|---|---|
| Injection molding | Yes | — |
| Default condition | Solid | — |
| Relative cost | $$ Standard | $$ Standard |
| 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 IR — frequently asked
Is IR stronger than EPDM?
Yes. IR has a typical tensile strength of 22 MPa (3.19 ksi) against 12 MPa (1.74 ksi) for EPDM — about 83% more.
Which is cheaper, EPDM or IR?
Both sit in the same relative cost tier ($$, standard); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which is easier to machine, EPDM or IR?
EPDM, by a small margin. Both rate poor for machinability — 30/100 against 25/100 for IR.
Ready to make it?
Upload a CAD file and FabDigit prices the part in EPDM and IR 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.