Silicone Foam (Sponge Rubber) RE41
Grade
RE41 = rE41/RE42
Pick when breathability, a very soft feel or high-temperature insulating padding is needed; the open cells take up water and dust, so avoid waterproof or dust-tight sealing duties.
Values for the RE41 condition
Other Silicone Foam (Sponge Rubber) grades and fills
Silicone Foam (Sponge Rubber) is listed in 9 conditions; see the grade overview at Silicone Foam (Sponge Rubber).
Compare all 9 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
RE41This page RE41/RE42 | Pick when breathability, a very soft feel or high-temperature insulating padding is needed; the open cells take up water and dust, so avoid waterproof or dust-tight sealing duties. | — | 0.6 | 150 | 10 Shore A |
Closed-cell silicone foam, soft | Choose the soft closed-cell grade (14–34 kPa at 25% deflection, 0.25 density) when thin plastic covers or sheet metal give low clamping force and must still seal at minimal compression load. | — | 0.8 | 180 | 12 Shore A |
Thermally conductive silicone foam | Pick as a compressible thermal interface pad between battery modules and power devices, combining 0.5 W/m·K conduction with low compression stress up to 200 °C. | — | 0.9 | 70 | 45 Shore A |
Ni/C or Ag filled | Use where an enclosure joint needs environmental sealing and EMI shielding at once; Ni/C or Ag filler drops volume resistivity to the Ω·cm range, at 0.85 g/cm³ density. | — | 1 | 80 | 45 Shore A |
FR (UL94 V-0 / HF-1) flame-retardant silicone foam | Choose for seals and insulating pads in rail transit, battery packs and electrical cabinets that must hold UL94 V-0/HF-1 or EN45545 approval, with service up to 200 °C. | — | 1 | 130 | 25 Shore A |
SCE42Default Closed-cell silicone foam, medium firmness | Use this medium-firmness closed-cell foam (34–62 kPa at 25% deflection) as the default gasket for enclosures, luminaires and outdoor electrical housings where clamping load is moderate. | — | 1 | 160 | 20 Shore A |
Closed-cell silicone foam, firm | Pick the firm closed-cell grade (62–90 kPa at 25% deflection) for gaskets, flange seals and vibration pads needing higher counterforce and resistance to shifting, at 130% elongation. | — | 2 | 130 | 28 Shore A |
SCE44/45 | Specify the extra-firm closed-cell grade (90–172 kPa at 25% deflection, 0.52 density) for high-clamp flanges and load-bearing insulation or anti-vibration pads needing maximum counterforce and least creep. | — | 2 | 110 | 35 Shore A |
Fabric / fiberglass-reinforced silicone sponge sheet | Choose for long strip gaskets, door and oven-door seals that must resist tearing and creep; fabric or glass reinforcement raises tensile strength to 6 MPa but cuts elongation to 25%. | — | 6 | 25 | 30 Shore A |
What is Silicone Foam (Sponge Rubber) RE41?
Silicone Foam (Sponge Rubber) RE41 is Silicone Foam (Sponge Rubber) in the RE41 grade — pick when breathability, a very soft feel or high-temperature insulating padding is needed; the open cells take up water and dust, so avoid waterproof or dust-tight sealing duties. Silicone Foam (Sponge Rubber) RE41 has a tensile strength of 0.6 MPa (0.087 ksi), weaker than 87% of polymer grades. Elongation at break is 150% and the elastic modulus is 8×10⁻⁴ GPa (1.16×10⁻⁴ Msi). Silicone Foam (Sponge Rubber) RE41 has a density of 0.24 g/cm³ (0.0087 lb/in³), lighter than 85% of polymer grades. Its glass-transition temperature is -123°C (-189 °F). SCE42 is the default condition FabDigit quotes; RE41 is available on request or by drawing note.
Advantages
- Forms and bends easily — 97/100, better than 100% of polymer grades
- Good corrosion resistance — 93/100, better than 95% of polymer grades
- Good UV / weathering resistance — 95/100, better than 95% of polymer grades
- Easy to machine — 85/100, better than 88% of polymer grades
- High service temperature — 200°C (392 °F), better than 87% of polymer grades
Limitations
- Absorbs moisture — dry before molding — 60%, worse than 100% of polymer grades
- Low stiffness — 8×10⁻⁴ GPa (1.16×10⁻⁴ Msi), worse than 98% of polymer grades
- High mold shrinkage — 3%, worse than 97% of polymer grades
- Poor heat conductor — 0.06 W/m·K (0.0318 BTU/hr·ft·°F), worse than 84% of polymer grades
Silicone Foam (Sponge Rubber) RE41 properties
Typical room-temperature values for Silicone Foam (Sponge Rubber) RE41; 17 are specific to this condition. Other listed values are Silicone Foam (Sponge Rubber) reference data and may not represent this condition. Bars are the position among polymer grades.
Physical3
Silicone Foam (Sponge Rubber) RE41 has a density of 0.24 g/cm³ (0.0087 lb/in³), lighter than 85% of polymer grades. Its glass-transition temperature is -123°C (-189 °F).
Mechanical8
Silicone Foam (Sponge Rubber) RE41 has a tensile strength of 0.6 MPa (0.087 ksi), weaker than 87% of polymer grades. Elongation at break is 150% and the elastic modulus is 8×10⁻⁴ GPa (1.16×10⁻⁴ Msi).
Thermal8
Silicone Foam (Sponge Rubber) RE41 is rated for continuous service to 200°C (392 °F). It conducts heat at 0.06 W/m·K (0.0318 BTU/hr·ft·°F), worse than 84% of polymer grades. Thermal expansion is 250 µm/m·K (138.9 µin/in·°F).
Electrical5
Silicone Foam (Sponge Rubber) RE41 is an electrical insulator with a dielectric strength of 5 kV/mm (127 V/mil) and a resistivity of 1×10¹¹ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (93/100), better than 95% of polymer grades. UV resistance is excellent.
Sustainability4
Producing a kilogram of Silicone Foam (Sponge Rubber) RE41 takes about 130 MJ of energy and emits 6.5 kg of CO₂ — more than 77% of polymer grades. Typical recycled content is 0%.
Manufacturability4
Silicone Foam (Sponge Rubber) RE41's machinability is excellent (85/100, better than 88% of polymer grades); formability excellent (97/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Silicone Foam (Sponge Rubber) RE41
Is Silicone Foam (Sponge Rubber) easy to machine?
Die cutting, waterjet, CNC oscillating knife and rotary die cutting are the practical methods; turning and milling are not suitable. Back the sheet with a cutting board and use sharp edges to avoid torn edges and stretch distortion.
Can Silicone Foam (Sponge Rubber) be welded?
Not heat weldable; join with silicone-specific adhesives such as self-fusing silicone tape or platinum/condensation-cure silicone, or mold butt-spliced closed loops.
Can Silicone Foam (Sponge Rubber) be formed, bent or molded?
The usual route is calendering followed by compression molding with blowing and vulcanization at 150-200 °C, then a 200 °C post-cure to remove volatiles; sponge cord and tube can also be extruded. Design closed-cell thickness tolerance at about ±10%.
What surface finishes work on Silicone Foam (Sponge Rubber)?
Plasma or primer treatment allows PSA lamination; plating and painting are not possible, so pigment the raw compound for colour. Avoid sulfur- or amine-bearing mould releases, which inhibit platinum cure.
Silicone Foam (Sponge Rubber) 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 |
|---|---|---|
| fumed / precipitated silica (reinforcingreinforcing filler | 15 – 35 | 25 |
| blowing agent (ADC/ OBSH) or expandable chemical blowing agent or thermally expandable microspheres | 1 – 6 | 3 |
| peroxide or Pt-complex curing systemperoxide or platinum catalyst | 0.3 – 2.5 | 1.2 |
| process aids / pigments / heat stabilizeprocess aids, color pastes, heat-resistance additives | 0.5 – 8 | 3 |
| flame-retardant / functional filler (Pt-added in flame-retardant, thermally or electrically conductive grades | 0 – 40 | 0 |
| polydimethylsiloxane (VMQ) base polymermethyl vinyl silicone rubber base gum | ≥ 45 (balance) | — |
Silicone Foam (Sponge Rubber) RE41 — frequently asked
What is Silicone Foam (Sponge Rubber) RE41 used for?
Silicone Foam (Sponge Rubber) RE41 is typically used for high-temperature gaskets and seals, EMI shielding gasket backing, aerospace door/duct seals and vibration dampening pads. In short: widest temperature range foam; low compression set; aerospace-qualified sponge.
What is the tensile strength of Silicone Foam (Sponge Rubber) RE41?
Silicone Foam (Sponge Rubber) RE41 has a typical tensile strength of 0.6 MPa (0.087 ksi) — weaker than 87% of polymer grades. Strength varies by condition: see the 9 listed tempers.
Is Silicone Foam (Sponge Rubber) RE41 easy to machine?
Yes — machinability is rated excellent (85/100, better than 88% of polymer grades). Die cutting, waterjet, CNC oscillating knife and rotary die cutting are the practical methods; turning and milling are not suitable. Back the sheet with a cutting board and use sharp edges to avoid torn edges and stretch distortion.
Can Silicone Foam (Sponge Rubber) RE41 be welded?
Not heat weldable; join with silicone-specific adhesives such as self-fusing silicone tape or platinum/condensation-cure silicone, or mold butt-spliced closed loops.
What surface finishes work on Silicone Foam (Sponge Rubber) RE41?
Plasma or primer treatment allows PSA lamination; plating and painting are not possible, so pigment the raw compound for colour. Avoid sulfur- or amine-bearing mould releases, which inhibit platinum cure.
Can Silicone Foam (Sponge Rubber) RE41 be formed, bent or molded?
The usual route is calendering followed by compression molding with blowing and vulcanization at 150-200 °C, then a 200 °C post-cure to remove volatiles; sponge cord and tube can also be extruded. Design closed-cell thickness tolerance at about ±10%.
What is the maximum service temperature of Silicone Foam (Sponge Rubber) RE41?
Silicone Foam (Sponge Rubber) RE41 is rated for continuous use to about 200°C (392 °F), and briefly to 260°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ASTM D1056 — Standard Specification for Flexible Cellular Materials, Sponge or Expanded Rubber — ASTM International (2020)
- ASTM D3574 / D395 — cellular material compression set and deflection test methods — ASTM International (2017)
- AMS 3195 — Silicone Rubber Sponge, Low-Temperature Resistant — SAE International (2019)
- BISCO HT-800/HT-820/HT-870 silicone foam data sheets — Rogers Corporation (2023)
- Silicone sponge and foam gasket material technical data — Stockwell Elastomerics (2023)
- Engineered Materials Handbook, Vol. 2: Engineering Plastics / elastomer data — ASM International (1988)
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.