Syntactic Foam (Epoxy)
Syntactic Foam (Epoxy) is a cast composite of hollow glass or polymer microspheres in an epoxy matrix, engineered for hydrostatic pressure resistance at low density (0.45 g/cm³ in the default class).
Reference datasheet — Syntactic Foam (Epoxy) is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the SF-45 condition
Syntactic Foam (Epoxy) grades and fills
Syntactic Foam (Epoxy) is supplied in 13 conditions, soft to hard. SF-45 is the default FabDigit quotes; the values on this page are for it.
Compare all 13 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
0.32 g/cm³ shallow-water buoyancy grade | Maximum buoyancy for ROV/AUV and float applications rated to roughly 1000 m depth. | 6 | |||
Macrosphere/composite buoyancy module | Lowest-density option for large riser and drilling buoyancy modules, made by potting glass macrospheres in syntactic foam. | 6 | 1 | 74 Shore D | |
Low-dielectric radome / antenna core grade | Very low density and loss tangent for radome cores, lenses and microwave absorber substrates. | 7 | 1.2 | 72 Shore D | |
0.38 g/cm³ mid-depth buoyancy grade | Balanced buoyancy/strength choice for work-class ROVs and 3000 m rated equipment. | 9 | 1.2 | 76 Shore D | |
Two-part pourable/castable syntactic compound | Field-mixed resin/microsphere paste for filling cavities, encapsulating cables and repairing buoyancy blocks. | 10 | 1.5 | 77 Shore D | |
SF-45Default 0.45 g/cm³ deep-water buoyancy grade | The workhorse deep-water grade: adequate buoyancy with a safe hydrostatic margin to about 6000 m. | 12 | 1.5 | 80 Shore D | |
Flame-retardant syntactic | For rail, marine interior and electronics enclosures needing V-0 and reduced smoke. | 13 | 1.2 | 82 Shore D | |
0.52 g/cm³ ultra-deep buoyancy grade | For hadal-zone floats and instrument housings where 7000–9000 m collapse margin is required. | 16 | 1.6 | 83 Shore D | |
High-temperature epoxy syntactic | Choose for downhole tools, engine-bay or thermally cycled aerospace cores where 120–170 °C service is needed. | 17 | 1.2 | 86 Shore D | |
Machinable epoxy syntactic tooling/model board | Dimensionally stable, low-CTE board for CNC master models, checking fixtures and vacuum-form tools. | 17 | 1 | 82 Shore D | |
0.60 g/cm³ full-ocean-depth grade | Full-ocean-depth landers and manned submersibles, where crush strength outranks buoyancy efficiency. | 20 | 1.8 | 85 Shore D | |
0.70 g/cm³ high-strength / structural core grade | Structural insert and load-bearing core grade where compressive strength, not buoyancy, governs. | 25 | 2 | 87 Shore D | |
Chopped carbon/glass fibre reinforced syntactic | Adds fibre to raise flexural strength, toughness and crack resistance where the foam is load-bearing or impacted. | 35 | 1 | 85 Shore D |
What is Syntactic Foam (Epoxy)?
Syntactic Foam (Epoxy) is a cast composite of hollow glass or polymer microspheres in an epoxy matrix, engineered for hydrostatic pressure resistance at low density (0.45 g/cm³ in the default class). It provides 12 MPa tensile strength, 2.4 GPa modulus and 0.12 W/m·K conductivity, and is supplied as machinable blocks, moulded buoyancy modules and pourable putty; density class sets the depth rating. It is a thermoset that cannot be welded, machined faces expose open cells and must be sealed, and the microsphere dust is abrasive and a respiratory hazard. Rigid PVC or PMI foam is the alternative where external pressure is low. Syntactic Foam (Epoxy) has a density of 0.45 g/cm³ (0.0163 lb/in³), lighter than 84% of polymer grades. Its glass-transition temperature is 100°C (212 °F). Syntactic Foam (Epoxy) has a tensile strength of 12 MPa (1.74 ksi), weaker than 76% of polymer grades. Elongation at break is 1.5% and the elastic modulus is 2.4 GPa (0.348 Msi).
What is Syntactic Foam (Epoxy) used for?
- Subsea buoyancy modules
- Deep-sea ROV/AUV floats
- Riser/cable buoyancy
- Aerospace tooling cores
Advantages
- Low, predictable mold shrinkage — 0.2%, better than 94% of polymer grades
- Lightweight — 0.45 g/cm³ (0.0163 lb/in³), better than 84% of polymer grades
- Low moisture uptake — 0.1%, better than 77% of polymer grades
Limitations
- Limited formability — 0/100, worse than 100% of polymer grades
- Limited ductility — 1.5%, worse than 98% of polymer grades
- Difficult to weld — 0/100, worse than 98% of polymer grades
- Hard to polish — 20/100, worse than 95% of polymer grades
- Low fracture toughness — 0.7 MPa·√m (0.637 ksi·√in), worse than 93% of polymer grades
Syntactic Foam (Epoxy) properties
Typical room-temperature values for Syntactic Foam (Epoxy)-SF-45; bars are the position among polymer grades.
Physical4
Syntactic Foam (Epoxy) has a density of 0.45 g/cm³ (0.0163 lb/in³), lighter than 84% of polymer grades. Its glass-transition temperature is 100°C (212 °F).
Mechanical15
Syntactic Foam (Epoxy) has a tensile strength of 12 MPa (1.74 ksi), weaker than 76% of polymer grades. Elongation at break is 1.5% and the elastic modulus is 2.4 GPa (0.348 Msi).
Thermal10
Syntactic Foam (Epoxy) is rated for continuous service to 80°C (176 °F). It conducts heat at 0.12 W/m·K (0.0693 BTU/hr·ft·°F), worse than 83% of polymer grades. Thermal expansion is 32 µm/m·K (17.8 µin/in·°F).
Electrical5
Syntactic Foam (Epoxy) is an electrical insulator with a dielectric strength of 9 kV/mm (228.6 V/mil) and a resistivity of 1×10¹² Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (85/100), better than 65% of polymer grades. UV resistance is fair.
Sustainability3
Producing a kilogram of Syntactic Foam (Epoxy) takes about 105 MJ of energy and emits 6 kg of CO₂ — more than 54% of polymer grades. Typical recycled content is 0%.
Manufacturability6
Syntactic Foam (Epoxy)'s machinability is good (60/100, better than 51% of polymer grades); weldability not recommended (0/100); formability not recommended (0/100).
Common Calculations4
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the polymer family
Yield strength against density for every polymer grade FabDigit runs. Syntactic Foam (Epoxy) is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Syntactic Foam (Epoxy)
Is Syntactic Foam (Epoxy) easy to machine?
Machines easily with sharp carbide or diamond tooling at high speed and low feed, dry with vacuum extraction; the glass microspheres are abrasive and the dust is a respiratory hazard, and cut faces are open-cell so they must be sealed or gelcoated.
Can Syntactic Foam (Epoxy) be welded?
Not weldable — a thermoset; joints are made with structural epoxy adhesive, and repairs use pourable syntactic putty of the same density class.
Can Syntactic Foam (Epoxy) be formed, bent or molded?
Produced by low-pressure casting, compression moulding or vacuum-assisted pouring of resin/microsphere paste into moulds, then oven cured and post-cured; avoid high pressure or aggressive mixing which crushes the microballoons and raises density.
Syntactic Foam (Epoxy) chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| hollow glass microspheressoda-lime-borosilicate microballoons, 10–120 µm, 0.2–0.6 g/cm³ true density; 50–65 vol% | 25 – 50 | 40 |
| silane coupling agent / additivesadhesion promoter, thixotrope, pigment | 0 – 2 | 1 |
| hollow polymer microspheres (optional)used in low-strength shallow-water and RF grades | 0 – 5 | 0 |
| chopped glass or carbon fibre (CF/GF var | 0 – 15 | 0 |
| epoxy resin + amine/anhydride hardener (DGEBA or DGEBF based, cured system | ≥ 45 (balance) |
What surface finishes work on Syntactic Foam (Epoxy)?
Sanded, then sealed with epoxy primer, polyurethane topcoat or elastomeric skin for UV, abrasion and long-term water-ingress protection; hardware is bonded in or potted rather than tapped into the foam.
Equivalent designations
Standards and trade names that resolve to Syntactic Foam (Epoxy) in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Also called
- Syntactic Foam
How much does Syntactic Foam (Epoxy) cost?
Syntactic Foam (Epoxy) is a high-cost polymer ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Syntactic Foam (Epoxy) — frequently asked
What is Syntactic Foam (Epoxy) used for?
Syntactic Foam (Epoxy) is typically used for subsea buoyancy modules, deep-sea ROV/AUV floats, riser/cable buoyancy and aerospace tooling cores. In short: pressure-resistant buoyancy foam; machinable structural core; abrasive microsphere dust.
What is the tensile strength of Syntactic Foam (Epoxy)?
Syntactic Foam (Epoxy) has a typical tensile strength of 12 MPa (1.74 ksi) — weaker than 76% of polymer grades. Strength varies by condition: see the 13 listed tempers.
Is Syntactic Foam (Epoxy) easy to machine?
Reasonably — machinability is rated good (60/100, better than 51% of polymer grades). Machines easily with sharp carbide or diamond tooling at high speed and low feed, dry with vacuum extraction; the glass microspheres are abrasive and the dust is a respiratory hazard, and cut faces are open-cell so they must be sealed or gelcoated.
Can Syntactic Foam (Epoxy) be welded?
Not readily — weldability is rated not recommended (0/100). Not weldable — a thermoset; joints are made with structural epoxy adhesive, and repairs use pourable syntactic putty of the same density class.
What surface finishes work on Syntactic Foam (Epoxy)?
Sanded, then sealed with epoxy primer, polyurethane topcoat or elastomeric skin for UV, abrasion and long-term water-ingress protection; hardware is bonded in or potted rather than tapped into the foam.
Can Syntactic Foam (Epoxy) be formed, bent or molded?
Produced by low-pressure casting, compression moulding or vacuum-assisted pouring of resin/microsphere paste into moulds, then oven cured and post-cured; avoid high pressure or aggressive mixing which crushes the microballoons and raises density.
What is the maximum service temperature of Syntactic Foam (Epoxy)?
Syntactic Foam (Epoxy) is rated for continuous use to about 80°C (176 °F), and briefly to 105°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does Syntactic Foam (Epoxy) cost?
Syntactic Foam (Epoxy) is a high-cost polymer ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- Subsea buoyancy syntactic foam grade tables (density vs. depth rating) — Trelleborg Offshore (2023)
- Deep-submergence syntactic foam and macrosphere buoyancy products — Engineered Syntactic Systems (ESS) (2022)
- ASM Handbook Vol. 21: Composites — syntactic foams and core materials — ASM International (2001)
- Structure and properties of hollow-particle-filled polymer composites (review data) — Journal of Materials Science / Gupta et al. (2014)
- ASTM D2842 — Water Absorption of Rigid Cellular Plastics — ASTM (2019)
- ASTM D1621 — Compressive Properties of Rigid Cellular Plastics — ASTM (2016)
- Epoxy syntactic tooling/model board technical data — Ebalta / Sika Advanced Resins (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.