Phenolic Foam vs Syntactic Foam (Epoxy)
Polymer · grade comparison
Phenolic 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 0.15 MPa (0.0218 ksi) for Phenolic Foam, about 80 times as much. In exchange, Phenolic Foam is the more ductile: elongation 2% versus 1.5% for Syntactic Foam (Epoxy). Phenolic Foam is lighter (0.05 g/cm³ vs 0.45 g/cm³ for Syntactic Foam (Epoxy)) and Syntactic Foam (Epoxy) is stiffer (2.4 GPa vs 0.01 GPa). On the shop floor, Phenolic Foam machines more easily (excellent vs good) and Phenolic Foam sits in a lower cost tier (standard, $$) than Syntactic Foam (Epoxy) (high, $$$$).
Phenolic FoamChoose it when the part is bent, formed or impact-loaded, or when weight is the constraint.
Syntactic Foam (Epoxy)Choose it when strength drives the design.
Phenolic 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.
Phenolic FoamSyntactic Foam (Epoxy)
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Elongation at Break
Compressive Strength
Compressive Modulus
Flexural Strength
Flexural Modulus
Shear Strength
Shear Modulus
Bulk Modulus
Fracture Toughness (K_IC)
Izod Impact, Notched
Hardness, Shore D
Hardness, Rockwell M
Physical
Density and transition temperatures.
Density
Water Absorption (24 h)
Water Absorption (Saturation)
Glass Transition (Tg)
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Min Service Temperature
Limiting Oxygen Index
Max Service Temperature (short-term)
Heat Deflection Temp. @ 0.45 MPa
Heat Deflection Temp. @ 1.8 MPa
Electrical
Conductivity and insulation.
Electrical Resistivity
Dielectric Constant (1 MHz)
Dielectric Strength
Dissipation Factor (1 MHz)
Volume Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
UV / Weathering Resistance
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%
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Thermal Diffusivity
Same in both: 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.
Manufacturing and finishing
| Capability | Phenolic Foam | Syntactic Foam (Epoxy) |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$ Standard | $$$$ High |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Phenolic Foam vs Syntactic Foam (Epoxy) — frequently asked
Is Syntactic Foam (Epoxy) stronger than Phenolic Foam?
Yes. Syntactic Foam (Epoxy) has a typical tensile strength of 12 MPa (1.74 ksi) against 0.15 MPa (0.0218 ksi) for Phenolic Foam — about 80 times as much.
Which is cheaper, Phenolic Foam or Syntactic Foam (Epoxy)?
Phenolic Foam is the lower-cost material: it sits in the standard tier ($$) while Syntactic Foam (Epoxy) 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, Phenolic Foam or Syntactic Foam (Epoxy)?
Phenolic Foam. Its machinability rates excellent (90/100) against good (60/100) for Syntactic Foam (Epoxy).
Ready to make it?
Upload a CAD file and FabDigit prices the part in Phenolic 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.