FEP vs PTFE
Polymer · grade comparison
FEP and PTFE are both polymer grades, both corrosion resistant plastic. FEP is the stronger of the two: yield strength 13 MPa (1.89 ksi) against 12 MPa (1.74 ksi) for PTFE, about 8% more. PTFE runs hotter in service (260°C vs 200°C continuous) and PTFE conducts heat better (0.25 W/m·K vs 0.2 W/m·K). On the shop floor, PTFE machines more easily (very good vs good), FEP welds better (very good vs not recommended), and PTFE sits in a lower cost tier (premium, $$$) than FEP (specialty, $$$$$).
FEPChoose it when strength drives the design, or when it will be welded.
PTFEChoose it when the part sees heat, or when the part is machined in volume.
FEP vs PTFE: 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)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Flexural Modulus
Izod Impact, Notched
Hardness, Rockwell R
Compressive Modulus
Flexural Strength
Shear Strength
Hardness, Shore A
Same in both: Shear Modulus 0.18 GPa0.03 Msi · Hardness, Shore D 56 Shore D
Physical
Density and transition temperatures.
Density
Melting Temperature (Tm)
Glass Transition (Tg)
Refractive Index
Light Transmission
Same in both: Water Absorption (24 h) 0.01% · Water Absorption (Saturation) 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)
Heat Deflection Temp. @ 0.45 MPa
Heat Deflection Temp. @ 1.8 MPa
Max Service Temperature (short-term)
Same in both: Min Service Temperature -200°C-328 °F · Limiting Oxygen Index 95%
Electrical
Conductivity and insulation.
Dielectric Strength
Dissipation Factor (1 MHz)
Surface Resistivity
Same in both: Electrical Resistivity 1×10¹⁶ Ω·m3.94×10²³ µΩ·in · Dielectric Constant (1 MHz) 2.1 · Volume Resistivity 1×10¹⁸ Ω·cm · Comparative Tracking Index (CTI) 600 V
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.
Machinability
Weldability
Formability (cold)
Polishability
Melt Flow Rate
Processing Melt Temperature (typ.)
Mold Temperature (typ.)
Same in both: Mold Shrinkage 4%
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)
Modulus of Resilience
Same in both: Specific Stiffness (E / density) 0.2 MN·m/kg · 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 | FEP | PTFE |
|---|---|---|
| Default condition | Unfilled | Virgin |
| Relative cost | $$$$$ Specialty | $$$ Premium |
| Min. machined wall | 0.5 mm | 0.5 mm |
| Best machined surface | Ra 0.8 µm | Ra 0.8 µm |
Both are offered for CNC machining, Sheet metal and Injection molding. Both take the same 6 finishes: Chrome Plating (Plastic), EMI Shielding Coating, Painting, Soft Touch Coating, Spray Painting, UV Coating.
FEP vs PTFE — frequently asked
Is FEP stronger than PTFE?
Yes. FEP has a typical yield strength of 13 MPa (1.89 ksi) against 12 MPa (1.74 ksi) for PTFE — about 8% more. Tensile strength is 23 MPa (3.34 ksi) vs 30 MPa (4.35 ksi).
Which is cheaper, FEP or PTFE?
PTFE is the lower-cost material: it sits in the premium 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 is easier to machine, FEP or PTFE?
PTFE. Its machinability rates very good (80/100) against good (55/100) for FEP; for welding the order is FEP first (very good, 80/100) then PTFE (not recommended, 10/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in FEP and PTFE 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.