Toray T700S fiber properties
Where to buy| Property | English | Metric | Method |
|---|---|---|---|
| Tensile strength | 711 ksi | 4,900 MPa | TY-030B-01 |
| Tensile modulus | 33.4 Msi | 230 GPa | TY-030B-01 |
| Strain at failure | 2.1% | 2.1% | TY-030B-01 |
| Density | 0.065 lb/in³ (converted) | 1.80 g/cm³ | TY-030B-02 |
| Filament diameter | 0.00028 in (converted) | 7 µm | — |
| Yield, 12K tow | 0.00054 lb/in (converted) | 800 g/1000 m | TY-030B-03 |
| CTE, axial | -0.38 × 10⁻⁶ /°C | -0.38 × 10⁻⁶ /°C | — |
Toray T700S data sheet, lot averages, "for reference purposes only" and "not intended for specification purposes". Conversions by The Aviation Point.
Same fiber in an epoxy laminate (unidirectional, 60% fiber volume)
| Property | English | Metric |
|---|---|---|
| Tensile strength | 415 ksi | 2,860 MPa |
| Tensile modulus | 19 Msi | 134 GPa |
| Compressive strength | 210 ksi | 1,450 MPa |
| Flexural strength | 245 ksi | 1,690 MPa |
| Interlaminar shear (ILSS) | 13 ksi | 86.9 MPa |
| 90° tensile strength | 12 ksi | 81 MPa |
Normalised to 60% fiber volume, cured with epoxy at 130 °C (266 °F). The laminate gets about 58% of the fiber strength (2,860 of 4,900 MPa), and the 90° tensile strength is only about 3% of the 0° value (81 of 2,860 MPa): the fiber carries the load, the resin does not.
Use and warnings
The FAA handbook calls carbon fiber very stiff and strong, 3 to 10 times stiffer than glass, used on floor beams, stabilizers, flight controls and primary fuselage and wing structure. Its disadvantages: lower conductivity than aluminium (so lightning protection mesh or coating), high cost, and a high potential for galvanic corrosion with metallic fasteners and structures (p. 7-5).
Toray lists the sizing types and resins they suit: 50C (epoxy, phenolic, polyester, vinyl ester), 60E (epoxy) and F0E (vinyl ester, compatible with epoxy). The tow is never twisted and comes in 6K, 12K and 24K.
Quick check
A carbon fairing needs an aluminium fitting bolted on. What does the FAA warn about?
- Nothing; carbon is inert.
Not this one. The handbook warns of a high potential for galvanic corrosion with metallic fasteners and structures.
- Carbon is cathodic and corrodes aluminium, so the pairing needs isolation per the SRM.
Best fit. Right: carbon is cathodic against aluminium; the manual says how to isolate.
- Only the fasteners matter.
Not this one. The warning covers fasteners and structures.
On a real job, the SRM decides.
Limits — when NOT to use this
- Fiber data are not laminate allowables. The repair uses the fabric, resin and ply schedule in the SRM.
- Lot averages. Toray says the data are not for specification.
- Not for aluminium contact. Carbon is cathodic: isolate it per the SRM.
Where to buy
Distributors coming soon.
Sources
- Toray Composite Materials America, TORAYCA T700S Standard Modulus Carbon Fiber Data Sheet (Rev. 11/24/2025) — fiber and composite properties, tow sizes, resin compatibility.
- FAA-H-8083-31B, AMT Handbook — Airframe, Volume 1 (2023), Chapter 7 — carbon and graphite fiber, uses and disadvantages (p. 7-5).