EPDM · grade
EPDM Sponge
Properties of the Sponge condition, compared with the other EPDM grades.
Pick for low-closure-force dust, water and acoustic sealing (cabinet gaskets, door seals) where compression load must stay low.
What is EPDM Sponge?
EPDM Sponge is EPDM in the Sponge grade — pick for low-closure-force dust, water and acoustic sealing (cabinet gaskets, door seals) where compression load must stay low. EPDM Sponge has a tensile strength of 2 MPa (0.29 ksi), weaker than 84% of polymer grades. Elongation at break is 200% and the elastic modulus is 0.01 GPa (8.7×10⁻⁴ Msi). EPDM Sponge has a density of 0.45 g/cm³ (0.0163 lb/in³), lighter than 84% of polymer grades. Its glass-transition temperature is -55°C (-67 °F). Solid is the default condition FabDigit quotes; Sponge is available on request or by drawing note.
Advantages
- Good UV / weathering resistance — 95/100, better than 95% of polymer grades
- Forms and bends easily — 90/100, better than 92% of polymer grades
- Lightweight — 0.45 g/cm³ (0.0163 lb/in³), better than 84% of polymer grades
- Ductile — tolerates forming and impact — 200%, better than 75% of polymer grades
Limitations
- Absorbs moisture — dry before molding — 3%, worse than 99% of polymer grades
- Hard to polish — 20/100, worse than 95% of polymer grades
- High mold shrinkage — 2.5%, worse than 93% of polymer grades
- Low stiffness — 0.01 GPa (8.7×10⁻⁴ Msi), worse than 87% of polymer grades
- Poor heat conductor — 0.08 W/m·K (0.0462 BTU/hr·ft·°F), worse than 83% of polymer grades
EPDM Sponge properties
Typical room-temperature values for EPDM Sponge — 10 properties are specific to this condition; the rest are grade-level values shared by every EPDM grade. Each bar shows where the value sits among the polymer grades in FabDigit's library — further right is higher.
Physical3
EPDM Sponge has a density of 0.45 g/cm³ (0.0163 lb/in³), lighter than 84% of polymer grades. Its glass-transition temperature is -55°C (-67 °F).
Mechanical9
EPDM Sponge has a tensile strength of 2 MPa (0.29 ksi), weaker than 84% of polymer grades. Elongation at break is 200% and the elastic modulus is 0.01 GPa (8.7×10⁻⁴ Msi).
Thermal8
EPDM Sponge is rated for continuous service to 110°C (230 °F). It conducts heat at 0.08 W/m·K (0.0462 BTU/hr·ft·°F), worse than 83% of polymer grades. Thermal expansion is 180 µm/m·K (100 µin/in·°F).
Electrical6
EPDM Sponge is an electrical insulator with a dielectric strength of 25 kV/mm (635 V/mil) and a resistivity of 1×10¹² Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (85/100), better than 63% of polymer grades. UV resistance is excellent.
Sustainability4
Producing a kilogram of EPDM Sponge takes about 95 MJ of energy and emits 4 kg of CO₂ — less than 70% of polymer grades. Typical recycled content is 5%.
Manufacturability7
EPDM Sponge's machinability is fair (45/100, worse than 77% of polymer grades); weldability poor (15/100); formability excellent (90/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other EPDM grades and fills
EPDM is also supplied in 12 other conditions. The full side-by-side table is on the EPDM overview.
- SolidDefaultDefault dense rubber for O-rings, gaskets, weatherstrip and hose where a pressure-tight, load-bearing seal is needed.12 MPa tensile
- SpongePick for low-closure-force dust, water and acoustic sealing (cabinet gaskets, door seals) where compression load must stay low.2 MPa tensile
Working with EPDM Sponge
Is EPDM easy to machine?
Best die-cut, waterjet or knife/CNC-blade cut with soap lubricant; milling and drilling smear and tear unless the part is frozen or a sharp hollow punch is used.
Can EPDM be welded?
Not thermally weldable — join by hot vulcanized splice, uncured tape splice, or cyanoacrylate/CR contact adhesive after abrasion plus primer.
Can EPDM be formed, bent or molded?
Mix on internal mixer/two-roll mill, then extrude profiles or compression/transfer/injection mold and vulcanize ~160–200 °C; sponge grades use chemical blowing agents with a matched slow cure.
What surface finishes work on EPDM?
Surface finish comes from the mold or extrusion die; flash removed by cryogenic deflashing, and paintability/bondability requires corona, plasma or chlorination pretreatment.
EPDM 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 |
|---|---|---|
| ethylene (C2 units)polymer C2 content; high-C2 grades are semi-crystalline | 45 – 75 | 60 |
| ENB diene (5-ethylidene-2-norbornene)cure site for sulfur vulcanization; DCPD/VNB used in some grades | 0.5 – 12 | 5 |
| carbon black (N550/N660)phr on polymer, in the compounded rubber | 20 – 90 | 60 |
| paraffinic process oilphr; oil-extended polymers supplied pre-oiled | 10 – 100 | 50 |
| calcium carbonate / clay fillerphr, cost filler | 0 – 80 | 30 |
| zinc oxide + stearic acidphr, activators | ≈ 6 | 6 |
| sulfur + accelerators or organic peroxidphr, cure system | 1 – 8 | 3 |
| propylene (C3 units)balance of polymer backbone | ≥ 20 (balance) | — |
EPDM Sponge — frequently asked
What is EPDM Sponge used for?
EPDM Sponge is typically used for automotive window and door weatherstrip, roofing membranes, steam and hot-water gaskets, coolant and radiator hoses, sponge sealing profiles for enclosures and HVAC duct and access-panel gaskets. In short: weatherproof rubber.
What is the tensile strength of EPDM Sponge?
EPDM Sponge has a typical tensile strength of 2 MPa (0.29 ksi) — weaker than 84% of polymer grades. Strength varies by condition: see the 13 listed tempers.
Is EPDM Sponge easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 77% of polymer grades). Best die-cut, waterjet or knife/CNC-blade cut with soap lubricant; milling and drilling smear and tear unless the part is frozen or a sharp hollow punch is used.
Can EPDM Sponge be welded?
Not readily — weldability is rated poor (15/100). Not thermally weldable — join by hot vulcanized splice, uncured tape splice, or cyanoacrylate/CR contact adhesive after abrasion plus primer.
What surface finishes work on EPDM Sponge?
Surface finish comes from the mold or extrusion die; flash removed by cryogenic deflashing, and paintability/bondability requires corona, plasma or chlorination pretreatment.
Can EPDM Sponge be formed, bent or molded?
Mix on internal mixer/two-roll mill, then extrude profiles or compression/transfer/injection mold and vulcanize ~160–200 °C; sponge grades use chemical blowing agents with a matched slow cure.
What is the maximum service temperature of EPDM Sponge?
EPDM Sponge is rated for continuous use to about 110°C (230 °F), and briefly to 160°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in EPDM Sponge?
Yes — EPDM Sponge is available for sheet metal and injection molding with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM D2000 — Rubber Products in Automotive Applications (classification AA/BA/CA/DA lines) — ASTM (2023)
- ASTM D1418 — Rubber and Rubber Latices Nomenclature (EPDM) — ASTM (2022)
- Vistalon EPDM grade and compound data — ExxonMobil Chemical (2023)
- Nordel IP EPDM technical information — Dow (2022)
- Keltan EPDM compounding guides — Arlanxeo (2023)
- ASM Engineered Materials Handbook Vol. 2 — Engineering Plastics/Elastomers — ASM International (1988)
- O-ring and elastomer chemical compatibility / property tables — Parker Hannifin O-Ring Handbook (2021)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.