PI Foam vs Syntactic Foam (Epoxy)
Polymer · grade comparison
PI Foam and Syntactic Foam (Epoxy) are both polymer grades. Syntactic Foam (Epoxy) is the stronger of the two: tensile strength 12 MPa (1.74 ksi) against 0.06 MPa (0.0087 ksi) for PI Foam, about 200 times as much. In exchange, PI Foam is the more ductile: elongation 15% versus 1.5% for Syntactic Foam (Epoxy). Syntactic Foam (Epoxy) is stiffer (2.4 GPa vs 3×10⁻⁴ GPa) and PI Foam runs hotter in service (300°C vs 80°C continuous).
PI FoamChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
Syntactic Foam (Epoxy)Choose it when strength drives the design.
PI Foam vs Syntactic Foam (Epoxy): propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all polymer 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 polymer 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
Tensile Strength (Ultimate)
Elongation at Break
Compressive Strength
Compressive Modulus
Tear Strength
Compression Set (22 h, 70 °C)
Shear Modulus
Bulk Modulus
Poisson's Ratio
Flexural Strength
Flexural Modulus
Shear Strength
Fracture Toughness (K_IC)
Izod Impact, Notched
Hardness, Shore D
Hardness, Rockwell M
Physical
Density and transition temperatures.
Glass Transition (Tg)
Density
Water Absorption (24 h)
Water Absorption (Saturation)
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Max Service Temperature (continuous)
Min Service Temperature
Limiting Oxygen Index
Max Service Temperature (short-term)
Thermal Expansion (CTE, 20–100 °C)
Heat Deflection Temp. @ 0.45 MPa
Heat Deflection Temp. @ 1.8 MPa
Electrical
Conductivity and insulation.
Electrical Resistivity
Dielectric Strength
Dielectric Constant (1 MHz)
Volume Resistivity
Dissipation Factor (1 MHz)
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
UV / Weathering Resistance
Same in both: Corrosion Resistance 85 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Formability (cold)
Polishability
Mold Shrinkage
Mold Temperature (typ.)
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Same in both: Typical Recycled Content 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.
Manufacturing and finishing
| Capability | PI Foam | Syntactic Foam (Epoxy) |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$$ High | $$$$ High |
| Min. machined wall | — | — |
| Best machined surface | — | — |
PI Foam vs Syntactic Foam (Epoxy) — frequently asked
Is Syntactic Foam (Epoxy) stronger than PI Foam?
Yes. Syntactic Foam (Epoxy) has a typical tensile strength of 12 MPa (1.74 ksi) against 0.06 MPa (0.0087 ksi) for PI Foam — about 200 times as much.
Which is cheaper, PI Foam or Syntactic Foam (Epoxy)?
Both sit in the same relative cost tier ($$$$, high); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which is easier to machine, PI Foam or Syntactic Foam (Epoxy)?
Syntactic Foam (Epoxy), by a small margin. Both rate good for machinability — 60/100 against 55/100 for PI Foam; for welding the order is PI Foam first (not recommended, 5/100) then Syntactic Foam (Epoxy) (not recommended, 0/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in PI Foam and Syntactic Foam (Epoxy) 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.