FabDigitFabDigit

C578 Type VIII vs EPS 150

Polymer · grade comparison

C578 Type VIII and EPS 150 are both polymer grades. EPS 150 is the stronger of the two: tensile strength 0.3 MPa (0.0435 ksi) against 0.2 MPa (0.029 ksi) for C578 Type VIII, about 50% more. In exchange, C578 Type VIII is the more ductile: elongation 2.5% versus 2% for EPS 150. C578 Type VIII is lighter (0.02 g/cm³ vs 0.03 g/cm³ for EPS 150) and EPS 150 is stiffer (0.01 GPa vs 0 GPa). On the shop floor, EPS 150 welds better (fair vs poor).

C578 Type VIIIChoose it when the part is bent, formed or impact-loaded, or when weight is the constraint.

EPS 150Choose it when strength drives the design, or when it will be welded.

C578 Type VIII vs EPS 150: properties

C578 Type VIIIEPS 150

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

0 GPa6.53×10⁻⁴ Msi
0.01 GPa0 Msi

Shear Modulus

0 GPa2.9×10⁻⁴ Msi
0 GPa5.8×10⁻⁴ Msi

Tensile Strength (Ultimate)

0.2 MPa0.03 ksi
0.3 MPa0.04 ksi

Elongation at Break

2.5%
2%

Compressive Strength

0.1 MPa0.01 ksi
0.16 MPa0.02 ksi

Compressive Modulus

0 GPa5.8×10⁻⁴ Msi
0.01 GPa0 Msi

Flexural Strength

0.24 MPa0.03 ksi
0.28 MPa0.04 ksi

Flexural Modulus

0.01 GPa7.25×10⁻⁴ Msi
0.01 GPa0 Msi

Shear Strength

0.11 MPa0.02 ksi
0.14 MPa0.02 ksi

Yield Strength (0.2% offset)

—
0.15 MPa0.02 ksi

Compression Set (22 h, 70 °C)

—
8%

Same in both: Poisson's Ratio 0.1

Physical

Density and transition temperatures.

Density

0.02 g/cm³6.86×10⁻⁴ lb/in³
0.03 g/cm³0 lb/in³

Water Absorption (24 h)

1.5%
1%

Water Absorption (Saturation)

3%
3.5%

Same in both: Glass Transition (Tg) 100°C212 °F

Thermal

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

Thermal Conductivity

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

Specific Heat Capacity

1,300 J/kg·K0.31 BTU/lb·°F
1,400 J/kg·K0.33 BTU/lb·°F

Max Service Temperature (continuous)

75°C167 °F
80°C176 °F

Vicat Softening Point (B50)

100°C212 °F
96°C205 °F

Max Service Temperature (short-term)

95°C203 °F
100°C212 °F

Same in both: Thermal Expansion (CTE, 20–100 °C) 65 µm/m·K36.1 µin/in·°F · Min Service Temperature -50°C-58 °F · Limiting Oxygen Index 25%

Electrical

Conductivity and insulation.

Electrical Resistivity

1×10¹⁴ Ω·m3.94×10²¹ µΩ·in
1×10¹³ Ω·m3.94×10²⁰ µΩ·in

Volume Resistivity

1×10¹⁶ Ω·cm
1×10¹⁵ Ω·cm

Same in both: Dielectric Constant (1 MHz) 1.03 · Dissipation Factor (1 MHz) 3×10⁻⁴

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

70 / 100
58 / 100

UV / Weathering Resistance

15 / 100
12 / 100

Manufacturability

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

Machinability

85 / 100
88 / 100

Weldability

20 / 100
40 / 100

Formability (cold)

15 / 100
25 / 100

Mold Shrinkage

0.8%
0.4%

Processing Melt Temperature (typ.)

—
115°C239 °F

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

105 MJ/kg45,142 BTU/lb
95 MJ/kg40,843 BTU/lb

Embodied Carbon (primary production)

3.6 kg CO₂/kg
3.3 kg CO₂/kg

Embodied Water

180 L/kg21.6 gal/lb
190 L/kg22.8 gal/lb

Same in both: Typical Recycled Content 5%

Common Calculations

Ratios derived from the values above.

Specific Stiffness (E / density)

0.2 MN·m/kg
0.3 MN·m/kg

Thermal Diffusivity

1.5 mm²/s
0.8 mm²/s

Same in both: Specific Strength (UTS / density) 11 kN·m/kg · Thermal Shock Resistance Index 0

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 scaleEPS 150

Manufacturing and finishing

CapabilityC578 Type VIIIEPS 150
Default condition——
Relative cost$$ Standard$$ Standard
Min. machined wall——
Best machined surface——

C578 Type VIII vs EPS 150 — frequently asked

Is EPS 150 stronger than C578 Type VIII?

Yes. EPS 150 has a typical tensile strength of 0.3 MPa (0.0435 ksi) against 0.2 MPa (0.029 ksi) for C578 Type VIII — about 50% more.

Which is cheaper, C578 Type VIII or EPS 150?

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 welds better, C578 Type VIII or EPS 150?

EPS 150. Its weldability rates fair (40/100) against poor (20/100) for C578 Type VIII.

Ready to make it?

Upload a CAD file and FabDigit prices the part in C578 Type VIII and EPS 150 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.