FEP · reinforced grade
FEP-GF20
Properties of the GF20 condition, compared with the other FEP grades.
Use where FEP's chemical resistance is needed but creep, stiffness and dimensional stability of the unfilled resin are inadequate.
What is FEP-GF20?
FEP-GF20 is FEP in the GF20 grade — use where FEP's chemical resistance is needed but creep, stiffness and dimensional stability of the unfilled resin are inadequate. FEP-GF20 has a yield strength of 13 MPa (1.89 ksi) and a tensile strength of 24 MPa (3.48 ksi) — weaker than 91% of polymer grades. Elongation at break is 15% and the elastic modulus is 0.48 GPa (0.0696 Msi). FEP-GF20 has a density of 2.25 g/cm³ (0.0813 lb/in³), heavier than 100% of polymer grades. Its glass-transition temperature is -90°C (-130 °F). Unfilled is the default condition FabDigit quotes; GF20 is available on request or by drawing note.
Advantages
- Good corrosion resistance — 98/100, better than 99% of polymer grades
- Good UV / weathering resistance — 98/100, better than 99% of polymer grades
- Low moisture uptake — 0.01%, better than 97% of polymer grades
- High service temperature — 205°C (401 °F), better than 88% of polymer grades
- Readily welded — 80/100, better than 84% of polymer grades
Limitations
- Heavy — 2.25 g/cm³ (0.0813 lb/in³), worse than 100% of polymer grades
- Low strength — 13 MPa (1.89 ksi), worse than 91% of polymer grades
- High embodied carbon — 12 kg CO₂/kg, worse than 91% of polymer grades
- High mold shrinkage — 2%, worse than 81% of polymer grades
- Difficult to machine — 45/100, worse than 77% of polymer grades
FEP-GF20 properties
Typical room-temperature values for FEP-GF20 — 9 properties are specific to this condition; the rest are grade-level values shared by every FEP grade. Each bar shows where the value sits among the polymer grades in FabDigit's library — further right is higher.
Physical7
FEP-GF20 has a density of 2.25 g/cm³ (0.0813 lb/in³), heavier than 100% of polymer grades. Its glass-transition temperature is -90°C (-130 °F).
Mechanical11
FEP-GF20 has a yield strength of 13 MPa (1.89 ksi) and a tensile strength of 24 MPa (3.48 ksi) — weaker than 91% of polymer grades. Elongation at break is 15% and the elastic modulus is 0.48 GPa (0.0696 Msi).
Thermal10
FEP-GF20 is rated for continuous service to 205°C (401 °F). It conducts heat at 0.2 W/m·K (0.116 BTU/hr·ft·°F), worse than 56% of polymer grades. Thermal expansion is 55 µm/m·K (30.6 µin/in·°F).
Electrical7
FEP-GF20 is an electrical insulator with a dielectric strength of 24 kV/mm (609.6 V/mil) and a resistivity of 1×10¹⁶ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (98/100), better than 99% of polymer grades. UV resistance is excellent.
Sustainability4
Producing a kilogram of FEP-GF20 takes about 220 MJ of energy and emits 12 kg of CO₂ — more than 90% of polymer grades. Typical recycled content is 0%.
Manufacturability8
FEP-GF20's machinability is fair (45/100, worse than 77% of polymer grades); weldability very good (80/100); formability very good (75/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other FEP grades and fills
FEP is also supplied in 5 other conditions. The full side-by-side table is on the FEP overview.
- UnfilledDefaultDefault choice for wire insulation, tubing, film and lined parts where full chemical inertness and clarity are wanted.23 MPa tensile
- GF20Use where FEP's chemical resistance is needed but creep, stiffness and dimensional stability of the unfilled resin are inadequate.24 MPa tensile
Working with FEP-GF20
Is FEP easy to machine?
Machines easily but is soft and springy — use sharp positive-rake carbide tools, high speed, light feed, and support thin walls; expect elastic recovery, so cut slightly oversize and allow parts to relax before final measurement.
Can FEP be welded?
Fully melt-fusible: hot-gas, heat-sealing, impulse and butt-fusion joining all work above ~300 °C; adhesive bonding requires sodium-etch or plasma surface treatment.
Can FEP be formed, bent or molded?
Extrude/injection mould at 315–380 °C melt with corrosion-resistant (Hastelloy/nickel-alloy) screws and dies; use ~200 °C tool temperature, slow cooling to limit voids, and mandatory HF-rated ventilation.
What surface finishes work on FEP?
Cannot be painted or plated without sodium-naphthalene etch or plasma activation; normally used as-moulded with a naturally low-friction, non-stick, translucent surface.
FEP chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| tetrafluoroethylene (TFE)wt% of copolymer backbone | 85 – 95 | 88 |
| hexafluoropropylene (HFP)comonomer that lowers Tm and enables melt processing | 5 – 15 | 12 |
| perfluoro(alkyl vinyl ether) (PPVE)optional third monomer in modified FEP (e.g. FEP-100 series) for crack resistance | 0 – 1 | 0.3 |
FEP-GF20 — frequently asked
What is FEP-GF20 used for?
FEP-GF20 is typically used for high-frequency coaxial cable insulation, corrosion-resistant tubing and pipe linings, transparent chemical labware, solar module and chemical process film, medical catheters and tubing and heat-shrink sleeving. In short: high-heat chemical resistant.
What is the yield strength of FEP-GF20?
FEP-GF20 has a typical yield strength of 13 MPa (1.89 ksi) and a tensile strength of 24 MPa (3.48 ksi) — weaker than 91% of polymer grades. Strength varies by condition: see the 6 listed tempers.
Is FEP-GF20 easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 77% of polymer grades). Machines easily but is soft and springy — use sharp positive-rake carbide tools, high speed, light feed, and support thin walls; expect elastic recovery, so cut slightly oversize and allow parts to relax before final measurement.
Can FEP-GF20 be welded?
Yes — weldability is rated very good (80/100). Fully melt-fusible: hot-gas, heat-sealing, impulse and butt-fusion joining all work above ~300 °C; adhesive bonding requires sodium-etch or plasma surface treatment.
What surface finishes work on FEP-GF20?
Cannot be painted or plated without sodium-naphthalene etch or plasma activation; normally used as-moulded with a naturally low-friction, non-stick, translucent surface.
Can FEP-GF20 be formed, bent or molded?
Extrude/injection mould at 315–380 °C melt with corrosion-resistant (Hastelloy/nickel-alloy) screws and dies; use ~200 °C tool temperature, slow cooling to limit voids, and mandatory HF-rated ventilation.
What is the maximum service temperature of FEP-GF20?
FEP-GF20 is rated for continuous use to about 205°C (401 °F), and briefly to 230°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in FEP-GF20?
Yes — FEP-GF20 is available for CNC machining, sheet metal and injection molding with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM D2116 – Standard Specification for FEP-Fluorocarbon Molding and Extrusion Materials — ASTM International (2018)
- ASTM D3159 – FEP Fluorocarbon Film (Extruded) — ASTM International (2015)
- Teflon FEP Fluoroplastic Resin – Properties Handbook — Chemours (formerly DuPont) (2019)
- Neoflon FEP Technical Information — Daikin Industries (2020)
- Dyneon FEP Product Comparison Guide — 3M / Dyneon (2018)
- Fluoroplastics Vol. 1 & 2 (Melt-Processible Fluoropolymers) — Ebnesajjad / Elsevier (2015)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.