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Rebond Foam vs SPF

Polymer · grade comparison

Rebond Foam and SPF are both polymer grades. SPF is the stronger of the two: tensile strength 0.3 MPa (0.0435 ksi) against 0.15 MPa (0.0218 ksi) for Rebond Foam, about 100% more. In exchange, Rebond Foam is the more ductile: elongation 60% versus 8% for SPF. SPF is lighter (0.03 g/cm³ vs 0.08 g/cm³ for Rebond Foam) and SPF is stiffer (0.01 GPa vs 8×10⁻⁴ GPa). On the shop floor, Rebond Foam welds better (poor vs not recommended).

Rebond FoamChoose it when the part is bent, formed or impact-loaded, or when it will be welded.

SPFChoose it when strength drives the design, or when weight is the constraint.

Rebond Foam vs SPF: properties

Rebond FoamSPF

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

8×10⁻⁴ GPa1.16×10⁻⁴ Msi
0.01 GPa7.25×10⁻⁴ Msi

Poisson's Ratio

0.3
0.33

Tensile Strength (Ultimate)

0.15 MPa0.02 ksi
0.3 MPa0.04 ksi

Yield Strength (0.2% offset)

0.02 MPa0 ksi
—

Elongation at Break

60%
8%

Compressive Strength

0.03 MPa0 ksi
0.2 MPa0.03 ksi

Compressive Modulus

6×10⁻⁴ GPa8.7×10⁻⁵ Msi
0.01 GPa8.7×10⁻⁴ Msi

Shear Strength

0.08 MPa0.01 ksi
0.18 MPa0.03 ksi

Hardness, Shore A

12 Shore A
—

Tear Strength

0.4 kN/m2.3 lbf/in
—

Compression Set (22 h, 70 °C)

10%
—

Flexural Strength

—
0.35 MPa0.05 ksi

Flexural Modulus

—
0.01 GPa8.7×10⁻⁴ Msi

Physical

Density and transition temperatures.

Density

0.08 g/cm³0 lb/in³
0.03 g/cm³0 lb/in³

Glass Transition (Tg)

-50°C-58 °F
110°C230 °F

Water Absorption (24 h)

—
1.5%

Water Absorption (Saturation)

—
4%

Thermal

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

Thermal Conductivity

0.05 W/m·K0.03 BTU/hr·ft·°F
0.02 W/m·K0.01 BTU/hr·ft·°F

Specific Heat Capacity

1,500 J/kg·K0.36 BTU/lb·°F
1,450 J/kg·K0.35 BTU/lb·°F

Min Service Temperature

-30°C-22 °F
-50°C-58 °F

Limiting Oxygen Index

19%
22%

Thermal Expansion (CTE, 20–100 °C)

—
70 µm/m·K38.9 µin/in·°F

Same in both: Max Service Temperature (continuous) 90°C194 °F · Max Service Temperature (short-term) 120°C248 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

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

Volume Resistivity

1×10¹² Ω·cm
1×10¹³ Ω·cm

Dielectric Constant (1 MHz)

—
1.1

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

55 / 100
80 / 100

UV / Weathering Resistance

20 / 100
15 / 100

Manufacturability

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

Machinability

80 / 100
85 / 100

Weldability

15 / 100
5 / 100

Formability (cold)

85 / 100
15 / 100

Polishability

—
5 / 100

Processing Melt Temperature (typ.)

—
45°C113 °F

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

20 MJ/kg8,598 BTU/lb
105 MJ/kg45,142 BTU/lb

Embodied Carbon (primary production)

1.3 kg CO₂/kg
5 kg CO₂/kg

Typical Recycled Content

90%
5%

Embodied Water

—
150 L/kg18 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

2 kN·m/kg
9 kN·m/kg

Specific Stiffness (E / density)

0 MN·m/kg
0.2 MN·m/kg

Thermal Diffusivity

0.4 mm²/s
0.5 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 FoamSPF
Default condition——
Relative cost$$ Standard$$ Standard
Min. machined wall——
Best machined surface——

Rebond Foam vs SPF — frequently asked

Is SPF stronger than Rebond Foam?

Yes. SPF has a typical tensile strength of 0.3 MPa (0.0435 ksi) against 0.15 MPa (0.0218 ksi) for Rebond Foam — about 100% more.

Which is cheaper, Rebond Foam or SPF?

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 SPF?

SPF. Its machinability rates excellent (85/100) against very good (80/100) for Rebond Foam; for welding the order is Rebond Foam first (poor, 15/100) then SPF (not recommended, 5/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in Rebond Foam and SPF 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.