ePTFE vs FEP
Polymer · grade comparison
ePTFE and FEP are both polymer grades. FEP is the stronger of the two: tensile strength 23 MPa (3.34 ksi) against 15 MPa (2.18 ksi) for ePTFE, about 53% more. FEP is the more ductile: elongation 320% versus 200% for ePTFE, and FEP is harder (56 Shore D vs 35 Shore D). EPTFE is lighter (0.7 g/cm³ vs 2.15 g/cm³ for FEP) and FEP is stiffer (0.48 GPa vs 0.2 GPa). On the shop floor, FEP welds better (very good vs poor) and ePTFE sits in a lower cost tier (high, $$$$) than FEP (specialty, $$$$$).
ePTFEChoose it when weight is the constraint, or when the part sees heat.
FEPChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.
ePTFE vs FEP: 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
Poisson's Ratio
Tensile Strength (Ultimate)
Elongation at Break
Compressive Strength
Hardness, Shore D
Compression Set (22 h, 70 °C)
Shear Modulus
Yield Strength (0.2% offset)
Flexural Modulus
Izod Impact, Notched
Hardness, Rockwell R
Physical
Density and transition temperatures.
Density
Melting Temperature (Tm)
Glass Transition (Tg)
Water Absorption (Saturation)
Refractive Index
Light Transmission
Same in both: Water Absorption (24 h) 0.01%
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. @ 0.45 MPa
Heat Deflection Temp. @ 1.8 MPa
Same in both: Limiting Oxygen Index 95%
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 1×10¹⁶ Ω·m3.94×10²³ µΩ·in · Volume Resistivity 1×10¹⁸ Ω·cm
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
UV / Weathering Resistance
Same in both: Corrosion Resistance 98 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Weldability
Formability (cold)
Processing Melt Temperature (typ.)
Polishability
Mold Shrinkage
Melt Flow Rate
Mold Temperature (typ.)
Same in both: Machinability 55 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Same in both: Typical Recycled Content 0%
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Same in both: Thermal Diffusivity 0.1 mm²/s · Thermal Shock Resistance Index 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.
Manufacturing and finishing
| Capability | ePTFE | FEP |
|---|---|---|
| CNC machining | — | Yes |
| Sheet metal | — | Yes |
| Injection molding | — | Yes |
| Default condition | — | Unfilled |
| Relative cost | $$$$ High | $$$$$ Specialty |
| Min. machined wall | — | 0.5 mm |
| Best machined surface | — | Ra 0.8 µm |
| Chrome Plating (Plastic) | — | Yes |
| EMI Shielding Coating | — | Yes |
| Painting | — | Yes |
| Soft Touch Coating | — | Yes |
| Spray Painting | — | Yes |
| UV Coating | — | Yes |
ePTFE vs FEP — frequently asked
Is FEP stronger than ePTFE?
Yes. FEP has a typical tensile strength of 23 MPa (3.34 ksi) against 15 MPa (2.18 ksi) for ePTFE — about 53% more.
Which is cheaper, ePTFE or FEP?
ePTFE is the lower-cost material: it sits in the high tier ($$$$) while FEP is specialty ($$$$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
Which welds better, ePTFE or FEP?
FEP. Its weldability rates very good (80/100) against poor (20/100) for ePTFE.
Ready to make it?
Upload a CAD file and FabDigit prices the part in ePTFE and FEP 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.