Kevlar 29 vs UHMWPE Fiber (Dyneema/Spectra)
Composite · grade comparison
Kevlar 29 and UHMWPE Fiber (Dyneema/Spectra) are both composite grades. UHMWPE Fiber (Dyneema/Spectra) is the stronger of the two: tensile strength 3,400 MPa (493 ksi) against 2,920 MPa (424 ksi) for Kevlar 29, about 16% more. UHMWPE Fiber (Dyneema/Spectra) is lighter (0.98 g/cm³ vs 1.44 g/cm³ for Kevlar 29) and UHMWPE Fiber (Dyneema/Spectra) is stiffer (109 GPa vs 70.5 GPa).
Kevlar 29Choose it when the part sees heat.
UHMWPE Fiber (Dyneema/Spectra)Choose it when strength drives the design, or when weight is the constraint.
Kevlar 29 vs UHMWPE Fiber (Dyneema/Spectra): propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all composite grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all composite grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Kevlar 29UHMWPE Fiber (Dyneema/Spectra)
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Shear Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Elongation at Break
Compressive Strength
Flexural Strength
Flexural Modulus
Shear Strength
Physical
Density and transition temperatures.
Density
Glass Transition (Tg)
Water Absorption (24 h)
Water Absorption (Saturation)
Melting Temperature (Tm)
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Min Service Temperature
Limiting Oxygen Index
Max Service Temperature (short-term)
Electrical
Conductivity and insulation.
Electrical Resistivity
Dielectric Constant (1 MHz)
Dissipation Factor (1 MHz)
Volume Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
UV / Weathering Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Polishability
Same in both: Machinability 25 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Same in both: Typical Recycled Content 0%
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Thermal Diffusivity
Strength versus weight
Yield strength against density for every composite grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Manufacturing and finishing
| Capability | Kevlar 29 | UHMWPE Fiber (Dyneema/Spectra) |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$$ High | $$$$ High |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Kevlar 29 vs UHMWPE Fiber (Dyneema/Spectra) — frequently asked
Is UHMWPE Fiber (Dyneema/Spectra) stronger than Kevlar 29?
Yes. UHMWPE Fiber (Dyneema/Spectra) has a typical tensile strength of 3,400 MPa (493 ksi) against 2,920 MPa (424 ksi) for Kevlar 29 — about 16% more.
Which is cheaper, Kevlar 29 or UHMWPE Fiber (Dyneema/Spectra)?
Both sit in the same relative cost tier ($$$$, high); the part price will be decided by machining time, tolerance and quantity rather than by the material.
When should I choose Kevlar 29 over UHMWPE Fiber (Dyneema/Spectra)?
Pick Kevlar 29 when the part sees heat. Pick UHMWPE Fiber (Dyneema/Spectra) when strength drives the design, or when weight is the constraint.
Ready to make it?
Upload a CAD file and FabDigit prices the part in Kevlar 29 and UHMWPE Fiber (Dyneema/Spectra) side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.
Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.