FabDigitFabDigit

G-9 vs XX

Composite · grade comparison

G-9 and XX are both composite grades. G-9 is the stronger of the two: tensile strength 240 MPa (34.8 ksi) against 120 MPa (17.4 ksi) for XX, about 100% more. XX is lighter (1.35 g/cm³ vs 1.95 g/cm³ for G-9) and G-9 is stiffer (19 GPa vs 8 GPa). On the shop floor, XX machines more easily (very good vs poor) and XX sits in a lower cost tier (standard, $$) than G-9 (high, $$$$).

G-9Choose it when strength drives the design, or when the part sees heat.

XXChoose it when weight is the constraint, or when the part is machined in volume.

G-9 vs XX: properties

G-9XX

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

19 GPa2.8 Msi
8 GPa1.2 Msi

Poisson's Ratio

0.16
0.25

Tensile Strength (Ultimate)

240 MPa34.8 ksi
120 MPa17.4 ksi

Compressive Strength

345 MPa50 ksi
250 MPa36.3 ksi

Compressive Modulus

15 GPa2.2 Msi
7 GPa1 Msi

Flexural Strength

310 MPa45 ksi
125 MPa18.1 ksi

Flexural Modulus

18 GPa2.6 Msi
7.5 GPa1.1 Msi

Shear Strength

120 MPa17.4 ksi
90 MPa13.1 ksi

Izod Impact, Notched

400 J/m7.5 ft·lbf/in
32 J/m0.6 ft·lbf/in

Hardness, Rockwell M

115 HRM
105 HRM

Elongation at Break

—
1.5%

Fracture Toughness (K_IC)

—
1.8 MPa·√m1.6 ksi·√in

Physical

Density and transition temperatures.

Density

1.95 g/cm³0.07 lb/in³
1.35 g/cm³0.05 lb/in³

Water Absorption (24 h)

0.8%
1.3%

Water Absorption (Saturation)

1.8%
4.5%

Glass Transition (Tg)

—
145°C293 °F

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

0.32 W/m·K0.18 BTU/hr·ft·°F
0.25 W/m·K0.14 BTU/hr·ft·°F

Specific Heat Capacity

1,100 J/kg·K0.26 BTU/lb·°F
1,400 J/kg·K0.33 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

14 µm/m·K7.8 µin/in·°F
25 µm/m·K13.9 µin/in·°F

Max Service Temperature (continuous)

155°C311 °F
120°C248 °F

Min Service Temperature

-60°C-76 °F
-50°C-58 °F

Limiting Oxygen Index

42%
28%

Max Service Temperature (short-term)

200°C392 °F
150°C302 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

1×10¹¹ Ω·m3.94×10¹⁸ µΩ·in
1×10¹⁰ Ω·m3.94×10¹⁷ µΩ·in

Dielectric Strength

12 kV/mm305 V/mil
15 kV/mm381 V/mil

Dielectric Constant (1 MHz)

6.5
5

Dissipation Factor (1 MHz)

0.03
0.04

Volume Resistivity

1×10¹³ Ω·cm
1×10¹² Ω·cm

Surface Resistivity

1×10¹² Ω
1×10¹¹ Ω

Comparative Tracking Index (CTI)

600 V
125 V

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

70 / 100
60 / 100

UV / Weathering Resistance

45 / 100
25 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

30 / 100
80 / 100

Polishability

20 / 100
30 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

100 MJ/kg42,992 BTU/lb
80 MJ/kg34,394 BTU/lb

Embodied Carbon (primary production)

6 kg CO₂/kg
4.5 kg CO₂/kg

Embodied Water

200 L/kg24 gal/lb
—

Same in both: Typical Recycled Content 0%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

123 kN·m/kg
89 kN·m/kg

Specific Stiffness (E / density)

9.7 MN·m/kg
5.9 MN·m/kg

Same in both: Thermal Diffusivity 0.1 mm²/s · Thermal Shock Resistance Index 0

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.

1101001,000510Density (g/cm³)Yield strength (MPa) — log scale

Manufacturing and finishing

CapabilityG-9XX
Default condition——
Relative cost$$$$ High$$ Standard
Min. machined wall——
Best machined surface——

G-9 vs XX — frequently asked

Is G-9 stronger than XX?

Yes. G-9 has a typical tensile strength of 240 MPa (34.8 ksi) against 120 MPa (17.4 ksi) for XX — about 100% more.

Which is cheaper, G-9 or XX?

XX is the lower-cost material: it sits in the standard tier ($$) while G-9 is high ($$$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.

Which is easier to machine, G-9 or XX?

XX. Its machinability rates very good (80/100) against poor (30/100) for G-9.

Ready to make it?

Upload a CAD file and FabDigit prices the part in G-9 and XX 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.