PTFE · reinforced grade
PTFE Glass Filled
Properties of the Glass Filled condition, compared with the other PTFE grades.
Pick for chemical-service seals, valve seats and slide bearings needing much lower creep and wear than virgin PTFE while keeping electrical insulation.
What is PTFE Glass Filled?
PTFE Glass Filled is PTFE in the Glass Filled grade — pick for chemical-service seals, valve seats and slide bearings needing much lower creep and wear than virgin PTFE while keeping electrical insulation. PTFE Glass Filled has a yield strength of 12 MPa (1.74 ksi) and a tensile strength of 17 MPa (2.47 ksi) — weaker than 93% of polymer grades. Elongation at break is 250% and the elastic modulus is 0.9 GPa (0.131 Msi). PTFE Glass Filled has a density of 2.25 g/cm³ (0.0813 lb/in³), heavier than 100% of polymer grades. Its glass-transition temperature is 126°C (259 °F). Virgin is the default condition FabDigit quotes; Glass Filled is available on request or by drawing note.
Advantages
- High service temperature — 260°C (500 °F), better than 97% of polymer grades
- Low moisture uptake — 0.01%, 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
- Ductile — tolerates forming and impact — 250%, better than 79% of polymer grades
Limitations
- Heavy — 2.25 g/cm³ (0.0813 lb/in³), worse than 100% of polymer grades
- High mold shrinkage — 4%, worse than 99% of polymer grades
- Hard to polish — 20/100, worse than 95% of polymer grades
- Low strength — 12 MPa (1.74 ksi), worse than 93% of polymer grades
- High embodied carbon — 9.5 kg CO₂/kg, worse than 90% of polymer grades
PTFE Glass Filled properties
Typical room-temperature values for PTFE Glass Filled — 14 properties are specific to this condition; the rest are grade-level values shared by every PTFE grade. Each bar shows where the value sits among the polymer grades in FabDigit's library — further right is higher.
Physical6
PTFE Glass Filled has a density of 2.25 g/cm³ (0.0813 lb/in³), heavier than 100% of polymer grades. Its glass-transition temperature is 126°C (259 °F).
Mechanical15
PTFE Glass Filled has a yield strength of 12 MPa (1.74 ksi) and a tensile strength of 17 MPa (2.47 ksi) — weaker than 93% of polymer grades. Elongation at break is 250% and the elastic modulus is 0.9 GPa (0.131 Msi).
Thermal10
PTFE Glass Filled 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 90 µm/m·K (50 µin/in·°F).
Electrical7
PTFE Glass Filled is an electrical insulator with a dielectric strength of 30 kV/mm (762 V/mil) and a resistivity of 1×10¹⁴ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (85/100), better than 63% of polymer grades. UV resistance is excellent.
Sustainability4
Producing a kilogram of PTFE Glass Filled takes about 210 MJ of energy and emits 9.5 kg of CO₂ — more than 90% of polymer grades. Typical recycled content is 0%.
Manufacturability6
PTFE Glass Filled's machinability is good (60/100, better than 51% of polymer grades); weldability not recommended (10/100); formability very good (70/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other PTFE grades and fills
PTFE is also supplied in 11 other conditions. The full side-by-side table is on the PTFE overview.
- VirginDefaultPick for maximum chemical inertness, lowest friction, best dielectric and FDA-compatible sealing where load and creep are low.30 MPa tensile
- Modified PTFEPick for permeation-tight linings, high-purity semiconductor fluid handling and thin welded/fused parts — finer structure, less cold flow and better weldability than standard PTFE.33 MPa tensile
- Polyimide FilledPick for seals running against soft or polished shafts (aluminium, stainless, ceramic coatings) where abrasive fillers are unacceptable but creep must be reduced.25 MPa tensile
- MoS2 FilledPick when hardness and wear must improve with almost no loss of virgin-PTFE strength, e.g. lightly loaded seals and static/dynamic gaskets.23 MPa tensile
- Glass FilledPick for chemical-service seals, valve seats and slide bearings needing much lower creep and wear than virgin PTFE while keeping electrical insulation.17 MPa tensile
- 30CFPTFE compound with 30 wt% chopped carbon fiber for maximum creep/wear resistance, high thermal conductivity and antistatic behaviour in dry-running and hydraulic seal service.17 MPa tensile
- Graphite FilledPick for non-lubricated rotary and reciprocating seals against soft counterfaces — lowest friction of the filled grades with good water/steam service.17 MPa tensile
- Carbon FilledPick for dry-running piston rings, compressor seals and hydraulic bearings needing high compressive strength, better heat removal and antistatic behaviour.15 MPa tensile
- 30GFPTFE compound with 30 wt% milled glass fiber giving the lowest creep and wear of the standard glass grades while keeping electrical insulation and broad chemical resistance (except HF and hot alkali).15 MPa tensile
- ePTFEPick for conformable flange gaskets, filtration/vent membranes and breathable laminates where a compressible microporous PTFE structure is needed.15 MPa tensile
- Bronze FilledPick for heavily loaded, high-PV dry bearings, wear rings and guide strips where thermal conduction and creep resistance matter more than chemical inertness.14 MPa tensile
Working with PTFE Glass Filled
Is PTFE easy to machine?
Machines easily with sharp positive-rake tools and high speed/low feed, but is soft and springy — expect elastic recovery, burr rollover and thermal-expansion-driven dimensional drift; stress-relieve stock and allow 24 h relaxation before final gauging.
Can PTFE be welded?
Cannot be solvent-bonded or conventionally hot-plate welded; joining is by fusion sintering above 360 °C under pressure, mechanical clamping, or adhesive bonding only after chemical/plasma or sodium-naphthalene surface etch.
Can PTFE be formed, bent or molded?
Not injection mouldable (melt viscosity ~10¹¹ Pa·s): granular resin is compression-preformed and free-sintered at 360–380 °C, paste resin is ram/paste extruded, and billets are skived into film or turned/machined; sintering shrinkage 3–6 % must be allowed.
What surface finishes work on PTFE?
Non-stick and non-paintable as moulded; use plasma, corona or sodium-etch pretreatment for printing/bonding, and expect no useful polish — surface finish is set by tooling and skiving quality.
PTFE 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 |
|---|---|---|
| Felemental fluorine content by weight | ≈ 76 | 76 |
| Celemental carbon content by weight | ≈ 24 | 24 |
| glass fiberonly in glass-filled compounds | 0 – 25 | 0 |
| carbon/graphiteonly in carbon/graphite-filled compounds | 0 – 25 | 0 |
| bronze (CuSn)only in bronze-filled bearing compounds | 0 – 60 | 0 |
| MoS2only in moly-filled compounds | 0 – 5 | 0 |
| tetrafluoroethylene (–CF2–CF2–) repeat uhomopolymer; modified PTFE contains ≤1 % PPVE/HFP comonomer | ≥ 99 (balance) | — |
PTFE Glass Filled — frequently asked
What is PTFE Glass Filled used for?
PTFE Glass Filled is typically used for seals, gaskets and liners. In short: zero-friction; non-stick.
What is the yield strength of PTFE Glass Filled?
PTFE Glass Filled has a typical yield strength of 12 MPa (1.74 ksi) and a tensile strength of 17 MPa (2.47 ksi) — weaker than 93% of polymer grades. Strength varies by condition: see the 12 listed tempers.
Is PTFE Glass Filled easy to machine?
Reasonably — machinability is rated good (60/100, better than 51% of polymer grades). Machines easily with sharp positive-rake tools and high speed/low feed, but is soft and springy — expect elastic recovery, burr rollover and thermal-expansion-driven dimensional drift; stress-relieve stock and allow 24 h relaxation before final gauging.
Can PTFE Glass Filled be welded?
Not readily — weldability is rated not recommended (10/100). Cannot be solvent-bonded or conventionally hot-plate welded; joining is by fusion sintering above 360 °C under pressure, mechanical clamping, or adhesive bonding only after chemical/plasma or sodium-naphthalene surface etch.
What surface finishes work on PTFE Glass Filled?
Non-stick and non-paintable as moulded; use plasma, corona or sodium-etch pretreatment for printing/bonding, and expect no useful polish — surface finish is set by tooling and skiving quality.
Can PTFE Glass Filled be formed, bent or molded?
Not injection mouldable (melt viscosity ~10¹¹ Pa·s): granular resin is compression-preformed and free-sintered at 360–380 °C, paste resin is ram/paste extruded, and billets are skived into film or turned/machined; sintering shrinkage 3–6 % must be allowed.
What is the maximum service temperature of PTFE Glass Filled?
PTFE Glass Filled 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.
Can FabDigit make parts in PTFE Glass Filled?
Yes — PTFE Glass Filled 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 D4894 / D4895 — PTFE Molding and Extrusion Materials — ASTM International (2022)
- ASTM D1710 — PTFE Rod, Heavy-Walled Tubing and Basic Shapes — ASTM International (2019)
- Engineered Materials Handbook Vol. 2: Engineering Plastics — ASM International (1988)
- Teflon PTFE fluoropolymer resin properties handbook — Chemours/DuPont (2021)
- TECAFLON PTFE stock shapes datasheet — Ensinger (2023)
- Dyneon PTFE / TFM modified PTFE product information — 3M Dyneon (2020)
- CAMPUS / plastics property datasets (fluoropolymers) — CWFG / CAMPUS consortium (2024)
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.