PTFE-GF25
A glass-fiber-reinforced PTFE compound giving markedly improved wear resistance, creep resistance and dimensional stability over unfilled PTFE at some cost to chemical inertness and dielectric properties.
Reference datasheet — PTFE-GF25 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the GF25 condition
PTFE-GF25 grades and fills
PTFE-GF25 is supplied in 6 conditions, soft to hard. GF25 is the default FabDigit quotes; the values on this page are for it.
Compare all 6 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
GF25Default 25% glass-fiber filled PTFE, compression moulded | Default general-purpose grade for valve seats, seals, wear rings and gaskets needing low creep and low friction. | 12 | 16 | 250 | 62 Shore D |
glass fiber plus molybdenum disulphide (bearing grade) | Pick when dry-running wear life and lower running friction matter more than colour or electrical properties (dark grey compound). | 12 | 14 | 200 | 63 Shore D |
GF25 milled-fiber | Choose for smoother sealing faces and more isotropic shrinkage in thin parts; slightly lower creep resistance than chopped fiber. | 12 | 15 | 260 | 61 Shore D |
GF25 ram-extruded rod / tube stock | Use for long machining stock in small diameters; properties slightly anisotropic and typically a few percent below moulded stock. | 12 | 15 | 230 | 62 Shore D |
GF25 FDA / food-contact compliant compound | Specify when food, pharma or potable-water contact compliance (FDA 21 CFR 177.1550 / EU 10/2011) is required — same mechanicals, certified virgin resin and filler. | 12 | 16 | 250 | 62 Shore D |
GF25 chopped-fiber | Choose for maximum creep/compression resistance in thick valve seats and heavily loaded wear parts. | 13 | 17 | 220 | 63 Shore D |
Supply forms, finishes and certifications
Ways PTFE-GF25 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
GF25-MLD-SHEET | GF25 compression-moulded billet / skived sheet | Supply form |
What is PTFE-GF25?
A glass-fiber-reinforced PTFE compound giving markedly improved wear resistance, creep resistance and dimensional stability over unfilled PTFE at some cost to chemical inertness and dielectric properties. PTFE-GF25 has a density of 2.23 g/cm³ (0.0806 lb/in³), heavier than 100% of polymer grades. PTFE-GF25 has a yield strength of 12 MPa (1.74 ksi) and a tensile strength of 16 MPa (2.32 ksi) — weaker than 88% of polymer grades. Elongation at break is 250% and the elastic modulus is 1.2 GPa (0.174 Msi).
What is PTFE-GF25 used for?
- Rotary shaft seals
- Piston rings
- Bearing pads and wear rings
- Valve seats
Advantages
- High service temperature — 260°C (500 °F), better than 97% of polymer grades
- Good UV / weathering resistance — 95/100, better than 95% of polymer grades
- Conducts heat well — 0.4 W/m·K (0.231 BTU/hr·ft·°F), better than 93% of polymer grades
- Low moisture uptake — 0.03%, better than 88% of polymer grades
- Ductile — tolerates forming and impact — 250%, better than 79% of polymer grades
Limitations
- Heavy — 2.23 g/cm³ (0.0806 lb/in³), worse than 100% of polymer grades
- Hard to polish — 20/100, worse than 95% of polymer grades
- High mold shrinkage — 2.5%, worse than 93% of polymer grades
- Difficult to weld — 5/100, worse than 89% of polymer grades
- Low strength — 12 MPa (1.74 ksi), worse than 88% of polymer grades
PTFE-GF25 properties
Typical room-temperature values for PTFE-GF25-GF25; bars are the position among polymer grades.
Physical4
PTFE-GF25 has a density of 2.23 g/cm³ (0.0806 lb/in³), heavier than 100% of polymer grades.
Mechanical14
PTFE-GF25 has a yield strength of 12 MPa (1.74 ksi) and a tensile strength of 16 MPa (2.32 ksi) — weaker than 88% of polymer grades. Elongation at break is 250% and the elastic modulus is 1.2 GPa (0.174 Msi).
Thermal10
PTFE-GF25 is rated for continuous service to 260°C (500 °F). It conducts heat at 0.4 W/m·K (0.231 BTU/hr·ft·°F), better than 93% of polymer grades. Thermal expansion is 75 µm/m·K (41.7 µin/in·°F).
Electrical7
PTFE-GF25 is an electrical insulator with a dielectric strength of 14 kV/mm (355.6 V/mil) and a resistivity of 1×10¹³ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (88/100), better than 74% of polymer grades. UV resistance is excellent.
Sustainability4
Producing a kilogram of PTFE-GF25 takes about 170 MJ of energy and emits 9 kg of CO₂ — more than 86% of polymer grades. Typical recycled content is 0%.
Manufacturability6
PTFE-GF25's machinability is very good (70/100, better than 74% of polymer grades); weldability not recommended (5/100); formability poor (30/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the polymer family
Yield strength against density for every polymer grade FabDigit runs. PTFE-GF25 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with PTFE-GF25
Is PTFE-GF25 easy to machine?
Machines easily with sharp positive-rake carbide (PCD for long runs) at high speed and light feed; glass is abrasive and the part is soft, so support thin walls, avoid heat build-up, and expect springback and burr rather than chips.
Can PTFE-GF25 be welded?
Not melt-weldable; join by mechanical clamping, adhesive bonding after sodium-etch/plasma surface activation, or by fusing to unfilled PTFE film during sintering.
Can PTFE-GF25 be formed, bent or molded?
Processed as a powder: cold compaction of a preform then free sintering at 370–380 °C with slow controlled cooling; not injection-mouldable and shrinkage on sinter is 2–5 %, so allow machining stock.
PTFE-GF25 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 |
|---|---|---|
| glass fiberE-glass, milled or chopped strand; wt % | 23 – 27 | 25 |
| polytetrafluoroethylene (PTFE)TFE homopolymer matrix, granular moulding resin | ≥ 73 (balance) |
What surface finishes work on PTFE-GF25?
Cannot be painted or plated as-is; use sodium-naphthalene etch or plasma treatment for bondable surfaces, and note that machined faces stay matte white/grey and cannot be polished to gloss.
Equivalent designations
Standards and trade names that resolve to PTFE-GF25 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Also called
- PTFE + 25% GF
How much does PTFE-GF25 cost?
PTFE-GF25 is a high-cost polymer ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
PTFE-GF25 — frequently asked
What is PTFE-GF25 used for?
PTFE-GF25 is typically used for rotary shaft seals, piston rings, bearing pads and wear rings and valve seats. In short: low-creep filled PTFE; cheapest PTFE wear compound; not for HF or strong alkali.
What is the yield strength of PTFE-GF25?
PTFE-GF25 has a typical yield strength of 12 MPa (1.74 ksi) and a tensile strength of 16 MPa (2.32 ksi) — weaker than 88% of polymer grades. Strength varies by condition: see the 6 listed tempers.
Is PTFE-GF25 easy to machine?
Yes — machinability is rated very good (70/100, better than 74% of polymer grades). Machines easily with sharp positive-rake carbide (PCD for long runs) at high speed and light feed; glass is abrasive and the part is soft, so support thin walls, avoid heat build-up, and expect springback and burr rather than chips.
Can PTFE-GF25 be welded?
Not readily — weldability is rated not recommended (5/100). Not melt-weldable; join by mechanical clamping, adhesive bonding after sodium-etch/plasma surface activation, or by fusing to unfilled PTFE film during sintering.
What surface finishes work on PTFE-GF25?
Cannot be painted or plated as-is; use sodium-naphthalene etch or plasma treatment for bondable surfaces, and note that machined faces stay matte white/grey and cannot be polished to gloss.
Can PTFE-GF25 be formed, bent or molded?
Processed as a powder: cold compaction of a preform then free sintering at 370–380 °C with slow controlled cooling; not injection-mouldable and shrinkage on sinter is 2–5 %, so allow machining stock.
What is the maximum service temperature of PTFE-GF25?
PTFE-GF25 is rated for continuous use to about 260°C (500 °F), and briefly to 300°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does PTFE-GF25 cost?
PTFE-GF25 is a high-cost polymer ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM D4745 — Filled and Unfilled PTFE Molding and Extrusion Materials — ASTM International (2021)
- ASTM D1710 — PTFE Rod, Heavy-Walled Tubing and Basic Shapes — ASTM International (2019)
- GB/T 5132 / GB/T 20020 — SAC (2019)
- Engineered Materials Handbook, Vol. 2: Engineering Plastics — ASM International (1988)
- Filled PTFE compound datasheets (glass-fiber grades) — Ensinger / Enflo / Daikin / Chemours licensees (2023)
- CAMPUS / UL Prospector fluoropolymer compound data — CWFG / UL (2024)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.