Kevlar 29 vs Kevlar 49
Composite · grade comparison
Kevlar 29 and Kevlar 49 are both composite grades. Kevlar 29 is the more ductile: elongation 3.6% versus 2.4% for Kevlar 49. Kevlar 49 is stiffer (112 GPa vs 70.5 GPa) and Kevlar 29 runs hotter in service (180°C vs 160°C continuous).
Kevlar 29Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
Kevlar 29 vs Kevlar 49: 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
Tensile Strength (Ultimate)
Elongation at Break
Compressive Strength
Same in both: Poisson's Ratio 0.36
Physical
Density and transition temperatures.
Water Absorption (24 h)
Water Absorption (Saturation)
Same in both: Density 1.44 g/cm³0.05 lb/in³ · Glass Transition (Tg) 360°C680 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 0.04 W/m·K0.02 BTU/hr·ft·°F · Specific Heat Capacity 1,420 J/kg·K0.34 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) -2 µm/m·K-1.1 µin/in·°F · Min Service Temperature -196°C-321 °F · Limiting Oxygen Index 29% · Max Service Temperature (short-term) 250°C482 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Resistivity 1×10¹³ Ω·m3.94×10²⁰ µΩ·in · Dielectric Constant (1 MHz) 4 · Dissipation Factor (1 MHz) 0.02 · Volume Resistivity 1×10¹⁵ Ω·cm
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: UV / Weathering Resistance 20 / 100
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)
Same in both: Thermal Diffusivity 0 mm²/s · Thermal Shock Resistance Index -1
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 | Kevlar 49 |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$$ High | $$$$ High |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Kevlar 29 vs Kevlar 49 — frequently asked
What is the difference between Kevlar 29 and Kevlar 49?
Kevlar 29 and Kevlar 49 are both composite grades. Kevlar 29 is the more ductile: elongation 3.6% versus 2.4% for Kevlar 49. Kevlar 49 is stiffer (112 GPa vs 70.5 GPa) and Kevlar 29 runs hotter in service (180°C vs 160°C continuous).
Which is cheaper, Kevlar 29 or Kevlar 49?
Both sit in the same relative cost tier ($$$$, 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 Kevlar 49?
Pick Kevlar 29 when the part is bent, formed or impact-loaded, or when the part sees heat.
Ready to make it?
Upload a CAD file and FabDigit prices the part in Kevlar 29 and Kevlar 49 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.