Basalt Fiber vs Kevlar 29
Composite · grade comparison
Basalt Fiber and Kevlar 29 are both composite grades. Kevlar 29 is the more ductile: elongation 3.6% versus 3.1% for Basalt Fiber. Kevlar 29 is lighter (1.44 g/cm³ vs 2.67 g/cm³ for Basalt Fiber) and Basalt Fiber is stiffer (89 GPa vs 70.5 GPa). On the shop floor, Basalt Fiber sits in a lower cost tier (standard, $$) than Kevlar 29 (high, $$$$).
Basalt FiberChoose it when the part sees heat, or when cost is the deciding factor.
Kevlar 29Choose it when the part is bent, formed or impact-loaded, or when weight is the constraint.
Basalt Fiber vs Kevlar 29: 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.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Shear Modulus
Bulk Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Elongation at Break
Compressive Strength
Physical
Density and transition temperatures.
Density
Water Absorption (24 h)
Water Absorption (Saturation)
Glass Transition (Tg)
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
Volume Resistivity
Dielectric Constant (1 MHz)
Dissipation Factor (1 MHz)
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 Shock Resistance Index
Same in both: Thermal Diffusivity 0 mm²/s
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 | Basalt Fiber | Kevlar 29 |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$ Standard | $$$$ High |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Basalt Fiber vs Kevlar 29 — frequently asked
What is the difference between Basalt Fiber and Kevlar 29?
Basalt Fiber and Kevlar 29 are both composite grades. Kevlar 29 is the more ductile: elongation 3.6% versus 3.1% for Basalt Fiber. Kevlar 29 is lighter (1.44 g/cm³ vs 2.67 g/cm³ for Basalt Fiber) and Basalt Fiber is stiffer (89 GPa vs 70.5 GPa).
Which is cheaper, Basalt Fiber or Kevlar 29?
Basalt Fiber is the lower-cost material: it sits in the standard tier ($$) while Kevlar 29 is high ($$$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
When should I choose Basalt Fiber over Kevlar 29?
Pick Basalt Fiber when the part sees heat, or when cost is the deciding factor. Pick Kevlar 29 when the part is bent, formed or impact-loaded, or when weight is the constraint.
Ready to make it?
Upload a CAD file and FabDigit prices the part in Basalt Fiber and Kevlar 29 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.