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Rebond Foam vs Semi-Rigid PU Foam

Polymer · grade comparison

Rebond Foam and Semi-Rigid PU Foam are both polymer grades. Semi-Rigid PU Foam is the stronger of the two: tensile strength 0.55 MPa (0.0798 ksi) against 0.15 MPa (0.0218 ksi) for Rebond Foam, about 3.7 times as much. Semi-Rigid PU Foam is the more ductile: elongation 70% versus 60% for Rebond Foam. Rebond Foam is lighter (0.08 g/cm³ vs 0.1 g/cm³ for Semi-Rigid PU Foam) and Semi-Rigid PU Foam is stiffer (0.01 GPa vs 8×10⁻⁴ GPa). On the shop floor, Rebond Foam machines more easily (very good vs good).

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

Semi-Rigid PU FoamChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.

Rebond Foam vs Semi-Rigid PU Foam: properties

Rebond FoamSemi-Rigid PU Foam

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

8×10⁻⁴ GPa1.16×10⁻⁴ Msi
0.01 GPa0 Msi

Tensile Strength (Ultimate)

0.15 MPa0.02 ksi
0.55 MPa0.08 ksi

Yield Strength (0.2% offset)

0.02 MPa0 ksi
—

Elongation at Break

60%
70%

Compressive Strength

0.03 MPa0 ksi
0.25 MPa0.04 ksi

Compressive Modulus

6×10⁻⁴ GPa8.7×10⁻⁵ Msi
0.01 GPa0 Msi

Shear Strength

0.08 MPa0.01 ksi
0.2 MPa0.03 ksi

Hardness, Shore A

12 Shore A
35 Shore A

Tear Strength

0.4 kN/m2.3 lbf/in
0.6 kN/m3.4 lbf/in

Flexural Strength

—
0.6 MPa0.09 ksi

Flexural Modulus

—
0.01 GPa0 Msi

Same in both: Poisson's Ratio 0.3 · Compression Set (22 h, 70 °C) 10%

Physical

Density and transition temperatures.

Density

0.08 g/cm³0 lb/in³
0.1 g/cm³0 lb/in³

Glass Transition (Tg)

-50°C-58 °F
60°C140 °F

Water Absorption (24 h)

—
8%

Water Absorption (Saturation)

—
40%

Thermal

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

Thermal Conductivity

0.05 W/m·K0.03 BTU/hr·ft·°F
0.04 W/m·K0.02 BTU/hr·ft·°F

Limiting Oxygen Index

19%
20%

Thermal Expansion (CTE, 20–100 °C)

—
70 µm/m·K38.9 µin/in·°F

Same in both: Specific Heat Capacity 1,500 J/kg·K0.36 BTU/lb·°F · Max Service Temperature (continuous) 90°C194 °F · Min Service Temperature -30°C-22 °F · Max Service Temperature (short-term) 120°C248 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

1×10¹⁰ Ω·m3.94×10¹⁷ µΩ·in
1×10⁹ Ω·m3.94×10¹⁶ µΩ·in

Volume Resistivity

1×10¹² Ω·cm
1×10¹¹ Ω·cm

Dielectric Constant (1 MHz)

—
1.15

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

55 / 100
70 / 100

UV / Weathering Resistance

20 / 100
25 / 100

Manufacturability

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

Machinability

80 / 100
55 / 100

Weldability

15 / 100
—

Formability (cold)

85 / 100
75 / 100

Mold Shrinkage

—
1%

Mold Temperature (typ.)

—
45°C113 °F

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

20 MJ/kg8,598 BTU/lb
100 MJ/kg42,992 BTU/lb

Embodied Carbon (primary production)

1.3 kg CO₂/kg
4.6 kg CO₂/kg

Typical Recycled Content

90%
5%

Embodied Water

—
300 L/kg35.9 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

2 kN·m/kg
6 kN·m/kg

Specific Stiffness (E / density)

0 MN·m/kg
0.1 MN·m/kg

Thermal Diffusivity

0.4 mm²/s
0.3 mm²/s

Strength versus weight

Yield strength against density for every polymer grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.

0.1110100123Density (g/cm³)Yield strength (MPa) — log scaleRebond Foam

Manufacturing and finishing

CapabilityRebond FoamSemi-Rigid PU Foam
Default condition——
Relative cost$$ Standard$$ Standard
Min. machined wall——
Best machined surface——

Rebond Foam vs Semi-Rigid PU Foam — frequently asked

Is Semi-Rigid PU Foam stronger than Rebond Foam?

Yes. Semi-Rigid PU Foam has a typical tensile strength of 0.55 MPa (0.0798 ksi) against 0.15 MPa (0.0218 ksi) for Rebond Foam — about 3.7 times as much.

Which is cheaper, Rebond Foam or Semi-Rigid PU Foam?

Both sit in the same relative cost tier ($$, standard); the part price will be decided by machining time, tolerance and quantity rather than by the material.

Which is easier to machine, Rebond Foam or Semi-Rigid PU Foam?

Rebond Foam. Its machinability rates very good (80/100) against good (55/100) for Semi-Rigid PU Foam.

Ready to make it?

Upload a CAD file and FabDigit prices the part in Rebond Foam and Semi-Rigid PU Foam 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.