PF GF
Reinforced grade
ASTM D700 · GB GB/T 34483
GF = glass-fiber filled (25–55 %) structural/electrical grade
Highest strength, stiffness and HDT phenolic — commutators, pump housings, ignition and under-hood parts.
Values for the GF condition
Other PF grades and fills
PF is listed in 10 conditions; see the grade overview at PF.
Compare all 10 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Friction/brake compound | Binder-based friction formulation for brake pads, linings and clutch facings — designed for stable µ at 300–400 °C flash temperatures. | — | 18 | 0.3 | 110 HRR |
Graphite / PTFE / MoS₂ lubricated bearing grade | Choose for dry-running bushings, thrust washers and water-lubricated marine bearings. | — | 40 | 0.5 | 105 HRM |
Mineral filled heat-resistant grade | Use for continuous 170–180 °C electrical service and better arc/heat resistance than wood-flour grades. | — | 42 | 0.4 | 115 HRM |
WFDefault Wood-flour / cellulose filled general purpose | The default low-cost black/brown molding compound for knobs, handles, switch bodies and closures. | — | 52 | 0.6 | 108 HRM |
As cast | Choose when a translucent/coloured, void-free polishable phenolic is needed (billiard balls, decorative rod, dominoes). | — | 55 | 1.2 | 100 HRM |
Cotton/rag (cellulose fabric) filled impact grade | Pick where phenolic must survive assembly shock or threaded/insert loading — 3–5× the notched impact of GP. | — | 55 | 1 | 100 HRM |
GFThis page Glass-fiber filled (25–55 %) structural/electrical grade | Highest strength, stiffness and HDT phenolic — commutators, pump housings, ignition and under-hood parts. | — | 85 | 0.7 | 118 HRM |
Paper-base phenolic laminate | Cheapest insulating sheet/rod stock; punchable at room or warm temperature for low-cost electrical panels and single-sided PCB base. | — | 85 | — | — |
Cotton-fabric phenolic laminate | Tough, machinable laminate for gears, bushings, wear strips and structural insulators where paper base is too brittle. | — | 95 | — | — |
Glass-fabric phenolic laminate | Highest-strength phenolic sheet for hot, humid structural-insulation duty where epoxy G-10 cost is not justified. | — | 220 | — | — |
What is PF GF?
PF GF is PF in the GF grade — highest strength, stiffness and HDT phenolic — commutators, pump housings, ignition and under-hood parts. PF GF has a tensile strength of 85 MPa (12.3 ksi), stronger than 85% of polymer grades. Elongation at break is 0.7% and the elastic modulus is 16 GPa (2.32 Msi). PF GF has a density of 1.85 g/cm³ (0.0668 lb/in³), heavier than 96% of polymer grades. Its glass-transition temperature is 160°C (320 °F). WF is the default condition FabDigit quotes; GF is available on request or by drawing note.
Advantages
- Stiff — 16 GPa (2.32 Msi), better than 99% of polymer grades
- Conducts heat well — 0.6 W/m·K (0.347 BTU/hr·ft·°F), better than 99% of polymer grades
- Low, predictable mold shrinkage — 0.2%, better than 94% of polymer grades
- High service temperature — 185°C (365 °F), better than 86% of polymer grades
Limitations
- Limited ductility — 0.7%, worse than 99% of polymer grades
- Difficult to weld — 0/100, worse than 98% of polymer grades
- Heavy — 1.85 g/cm³ (0.0668 lb/in³), worse than 96% of polymer grades
- Limited formability — 5/100, worse than 95% of polymer grades
- Low fracture toughness — 1 MPa·√m (0.91 ksi·√in), worse than 87% of polymer grades
PF GF properties
Typical room-temperature values for PF GF; 16 are specific to this condition. Other listed values are PF reference data and may not represent this condition. Bars are the position among polymer grades.
Physical4
PF GF has a density of 1.85 g/cm³ (0.0668 lb/in³), heavier than 96% of polymer grades. Its glass-transition temperature is 160°C (320 °F).
Mechanical14
PF GF has a tensile strength of 85 MPa (12.3 ksi), stronger than 85% of polymer grades. Elongation at break is 0.7% and the elastic modulus is 16 GPa (2.32 Msi).
Thermal10
PF GF is rated for continuous service to 185°C (365 °F). It conducts heat at 0.6 W/m·K (0.347 BTU/hr·ft·°F), better than 99% of polymer grades. Thermal expansion is 18 µm/m·K (10 µin/in·°F).
Electrical7
PF GF is an electrical insulator with a dielectric strength of 14 kV/mm (355.6 V/mil) and a resistivity of 1×10¹⁰ Ω·m.
Chemical & Environmental3
Corrosion resistance is good (68/100), worse than 85% of polymer grades. UV resistance is poor.
Sustainability4
Producing a kilogram of PF GF takes about 87 MJ of energy and emits 4 kg of CO₂ — less than 77% of polymer grades. Typical recycled content is 0%.
Manufacturability7
PF GF's machinability is fair (35/100, worse than 84% of polymer grades); weldability not recommended (0/100); formability not recommended (5/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with PF GF
Is PF easy to machine?
Machines easily but is abrasive and dusty — use carbide or PCD tools, positive rake, sharp edges, high speed with light feed and vacuum dust extraction; no coolant needed on laminates.
Can PF be welded?
Not weldable (thermoset); join by fasteners, molded-in inserts, or structural adhesives (epoxy) after abrading and degreasing.
Can PF be formed, bent or molded?
Compression and transfer molding at 150–190 °C mold with 15–35 MPa and 15–30 s/mm cure; preheat (RF or IR) to 90–110 °C to shorten cure; vent to release condensation water and ammonia.
What surface finishes work on PF?
Molded parts release with a glossy skin; deflash by tumbling or media blast, then buff/wax-polish for cast grades; paint or plate only after alkaline etch and a primer — plating adhesion is fair at best.
PF 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 |
|---|---|---|
| phenol-formaldehyde resin (novolac/resolmatrix binder | 35 – 55 | 45 |
| wood flour / cellulose fillerdefault GP filler; replaced by mineral, cotton or glass in other variants | 35 – 55 | 45 |
| hexamethylenetetramine (hexa) curing ageon resin basis for novolac systems | 5 – 12 | 8 |
| lime / magnesium oxideacid scavenger, cure accelerator | 0.5 – 3 | 1.5 |
| stearate lubricant / mold release | 0.5 – 2 | 1 |
| carbon black / pigmentphenolics are only available in dark colors | 0.5 – 3 | 1.5 |
PF GF — frequently asked
What is PF GF used for?
PF GF is typically used for electrical switchgear, brake pads/friction parts, cookware handles and bakelite housings. In short: lowest-cost high-heat thermoset; 150 °C continuous service; machinable laminate stock.
What is the tensile strength of PF GF?
PF GF has a typical tensile strength of 85 MPa (12.3 ksi) — stronger than 85% of polymer grades. Strength varies by condition: see the 10 listed tempers.
Is PF GF easy to machine?
Not especially — machinability is rated fair (35/100, worse than 84% of polymer grades). Machines easily but is abrasive and dusty — use carbide or PCD tools, positive rake, sharp edges, high speed with light feed and vacuum dust extraction; no coolant needed on laminates.
Can PF GF be welded?
Not readily — weldability is rated not recommended (0/100). Not weldable (thermoset); join by fasteners, molded-in inserts, or structural adhesives (epoxy) after abrading and degreasing.
What surface finishes work on PF GF?
Molded parts release with a glossy skin; deflash by tumbling or media blast, then buff/wax-polish for cast grades; paint or plate only after alkaline etch and a primer — plating adhesion is fair at best.
Can PF GF be formed, bent or molded?
Compression and transfer molding at 150–190 °C mold with 15–35 MPa and 15–30 s/mm cure; preheat (RF or IR) to 90–110 °C to shorten cure; vent to release condensation water and ammonia.
What is the maximum service temperature of PF GF?
PF GF is rated for continuous use to about 185°C (365 °F), and briefly to 190°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ASTM D700 — Standard Specification for Phenolic Molding Compounds — ASTM International (2021)
- ISO 14526 Plastics — Phenolic powder moulding compounds (PF-PMCs) — ISO (2020)
- Engineered Materials Handbook Vol.2: Engineering Plastics — Phenolics — ASM International (1988)
- NEMA LI 1 — Industrial Laminated Thermosetting Products (grades X, XX, XPC, C, CE, L, LE, G-3) — NEMA (1998)
- Phenolic molding compound and laminate technical datasheets — Hexion / Sumitomo Bakelite / Ensinger (2023)
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.