Epoxy CF
Reinforced grade
ASTM D1763 · GB GB/T 13657 · ISO 3673-1
CF = carbon fiber / epoxy composite
Use when epoxy acts as the matrix of a structural CFRP laminate — highest specific stiffness, near-zero axial CTE.
Values for the CF condition
Other Epoxy grades and fills
Epoxy is listed in 10 conditions; see the grade overview at Epoxy.
Compare all 10 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Syntactic foam / microballoon-filled low-density grade | Buoyancy modules, core materials and lightweight tooling fills where compressive strength per density rules. | — | 20 | 1.2 | 80 Shore D |
ESD / electrically conductive | Conductive adhesives, EMI/grounding bondlines and static-dissipative tooling surfaces. | — | 30 | 0.5 | 90 Shore D |
Thermally conductive | Gap fillers and heat-sink potting where 1–3 W/m·K is needed while keeping electrical insulation. | — | 40 | 0.8 | 90 Shore D |
Toughened / impact-modified | Structural adhesives and crash-tolerant bondlines — 3–5× fracture toughness at the cost of Tg and modulus. | — | 45 | 9 | 78 Shore D |
Mineral / silica filled encapsulation grade | Silica-filled potting/encapsulation compound — low CTE and shrinkage for electronics, transformers and semiconductor molding. | — | 55 | 1 | — |
FR | Brominated or phosphorus/ATH flame-retarded formulation for electrical enclosures, busbar and rail applications. | — | 55 | 2 | 88 Shore D |
High-Tg novolac / anhydride cured heat-resistant grade | For tooling, aerospace prepreg and under-hood parts needing service to ~180–200 °C; more brittle and needs high-temperature post-cure. | — | 70 | 1.8 | — |
30 % short glass fiber reinforced epoxy molding compound | Choose for stiff, dimensionally stable molded parts (encapsulation, electrical housings) where CTE must be halved versus neat resin. | — | 110 | 1.5 | — |
FR-4 / G-10 | Pick for PCB substrates, insulating plates and machined electrical parts needing high flexural strength plus V-0 rating. | — | 310 | — | — |
CFThis page Carbon fiber / epoxy composite | Use when epoxy acts as the matrix of a structural CFRP laminate — highest specific stiffness, near-zero axial CTE. | — | 1,800 | 1.4 | — |
What is Epoxy CF?
Epoxy CF is Epoxy in the CF grade — use when epoxy acts as the matrix of a structural CFRP laminate — highest specific stiffness, near-zero axial CTE. Epoxy CF has a tensile strength of 1,800 MPa (261 ksi), stronger than 100% of polymer grades. Elongation at break is 1.4% and the elastic modulus is 135 GPa (19.6 Msi). Epoxy CF has a density of 1.55 g/cm³ (0.056 lb/in³), heavier than 91% of polymer grades. Its glass-transition temperature is 120°C (248 °F).
Advantages
- Stiff — 135 GPa (19.6 Msi), better than 100% of polymer grades
- Conducts heat well — 5 W/m·K (2.89 BTU/hr·ft·°F), better than 100% of polymer grades
- Low, predictable mold shrinkage — 0.2%, better than 94% of polymer grades
- Polishes to a fine finish — 75/100, better than 86% of polymer grades
Limitations
- Limited ductility — 1.4%, worse than 98% of polymer grades
- Difficult to weld — 0/100, worse than 98% of polymer grades
- Low fracture toughness — 0.6 MPa·√m (0.546 ksi·√in), worse than 96% of polymer grades
- Limited formability — 5/100, worse than 95% of polymer grades
- Difficult to machine — 25/100, worse than 93% of polymer grades
Epoxy CF properties
Typical room-temperature values for Epoxy CF; 13 are specific to this condition. Other listed values are Epoxy reference data and may not represent this condition. Bars are the position among polymer grades.
Physical6
Epoxy CF has a density of 1.55 g/cm³ (0.056 lb/in³), heavier than 91% of polymer grades. Its glass-transition temperature is 120°C (248 °F).
Mechanical15
Epoxy CF has a tensile strength of 1,800 MPa (261 ksi), stronger than 100% of polymer grades. Elongation at break is 1.4% and the elastic modulus is 135 GPa (19.6 Msi).
Thermal10
Epoxy CF is rated for continuous service to 120°C (248 °F). It conducts heat at 5 W/m·K (2.89 BTU/hr·ft·°F), better than 100% of polymer grades. Thermal expansion is 0.5 µm/m·K (0.278 µin/in·°F).
Electrical7
Epoxy CF is an electrical insulator with a dielectric strength of 20 kV/mm (508 V/mil) and a resistivity of 0.01 Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (82/100), better than 56% of polymer grades. UV resistance is poor.
Sustainability4
Producing a kilogram of Epoxy CF takes about 137 MJ of energy and emits 6.6 kg of CO₂ — more than 80% of polymer grades. Typical recycled content is 0%.
Manufacturability6
Epoxy CF's machinability is poor (25/100, worse than 93% 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 Epoxy CF
Is Epoxy easy to machine?
Machines cleanly with sharp carbide (PCD for filled/laminate grades) at high speed, light feed and no coolant heat build-up; filled and glass-cloth grades are highly abrasive and the dust requires extraction.
Can Epoxy be welded?
Thermoset — cannot be welded or re-melted; joints are made by secondary epoxy bonding with abraded, solvent-cleaned surfaces.
Can Epoxy be formed, bent or molded?
Processed by casting, potting, RTM/infusion, prepreg lay-up, filament winding or transfer/compression molding; degas the mix, respect pot life, and post-cure (typically 80–180 °C) to develop full Tg.
What surface finishes work on Epoxy?
Sands and polishes to a high gloss; accepts paint and primers readily after abrasion; needs UV-blocking topcoat or clearcoat for outdoor service because aromatic epoxies yellow and chalk.
Epoxy 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 |
|---|---|---|
| bisphenol-A diglycidyl ether (DGEBA) resE-51/E-44 type; novolac or cycloaliphatic epoxies substitute in HT/clear grades | 45 – 75 | 60 |
| amine or anhydride hardenerpolyamine, polyamide, DDS/DDM or MTHPA anhydride; stoichiometry set by EEW | 8 – 40 | 25 |
| reactive diluent / flexibilizere.g. BGE, C12-14 glycidyl ether, CTBN | 0 – 15 | 5 |
| mineral or glass fillersilica, alumina, glass fiber/cloth depending on variant | 0 – 70 | 0 |
| accelerator / additivesimidazole, BDMA, defoamer, pigment, FR package | 0 – 3 | 1 |
Epoxy CF — frequently asked
What is Epoxy CF used for?
Epoxy CF is typically used for composite laminates, structural adhesives, potting/encapsulation and tooling and molds. In short: baseline composite matrix; strongest structural adhesive resin; wide filled-grade range.
What is the tensile strength of Epoxy CF?
Epoxy CF has a typical tensile strength of 1,800 MPa (261 ksi) — stronger than 100% of polymer grades. Strength varies by condition: see the 10 listed tempers.
Is Epoxy CF easy to machine?
Not especially — machinability is rated poor (25/100, worse than 93% of polymer grades). Machines cleanly with sharp carbide (PCD for filled/laminate grades) at high speed, light feed and no coolant heat build-up; filled and glass-cloth grades are highly abrasive and the dust requires extraction.
Can Epoxy CF be welded?
Not readily — weldability is rated not recommended (0/100). Thermoset — cannot be welded or re-melted; joints are made by secondary epoxy bonding with abraded, solvent-cleaned surfaces.
What surface finishes work on Epoxy CF?
Sands and polishes to a high gloss; accepts paint and primers readily after abrasion; needs UV-blocking topcoat or clearcoat for outdoor service because aromatic epoxies yellow and chalk.
Can Epoxy CF be formed, bent or molded?
Processed by casting, potting, RTM/infusion, prepreg lay-up, filament winding or transfer/compression molding; degas the mix, respect pot life, and post-cure (typically 80–180 °C) to develop full Tg.
What is the maximum service temperature of Epoxy CF?
Epoxy CF is rated for continuous use to about 120°C (248 °F), and briefly to 180°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- Engineered Materials Handbook Vol. 2 — Engineering Plastics — ASM International (1988)
- Engineered Materials Handbook Vol. 1 — Composites — ASM International (1987)
- ASTM D1763 — Standard Specification for Epoxy Resins — ASTM (2019)
- GB/T 13657 — Bisphenol-A epoxy resin — SAC (2011)
- IEC 61249 / NEMA LI-1 (FR-4, G-10 laminates) — IEC / NEMA (2020)
- Araldite / Aradur casting and adhesive system datasheets — Huntsman Advanced Materials (2023)
- EPON / EPIKURE resin technical data — Hexion (Westlake Epoxy) (2022)
- CES EduPack polymer records — epoxy (thermoset) — Ansys Granta (2022)
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.