Sponge Silicone Sheet: Closed Cell, Medium Density
Silicone sponge sheet is a lightweight, closed‑cell elastomer engineered for sealing, cushioning, insulation, and vibration damping in demanding environments. ElastaPro manufactures medium‑density silicone sponge sheets and rolls in medium density and multiple thicknesses and grades to support gasketing, enclosure sealing, thermal protection, and outdoor applications where long‑term durability is essential.
ElastaPro’s materials are available in continuous rolls up to 1/2” thick and in sheets up to 2” thick. The surface has a fine fabric finish. ElastaPro can slit medium-density, closed cell silicone at various widths, and we can apply a pressure sensitive adhesive (PSA) to help you speed installation. Our silicone sponge materials combine excellent compression recovery with outstanding resistance to temperature extremes, UV, ozone, and environmental exposure—making them a reliable choice for both indoor and outdoor sealing challenges.
Closed Cell Silicone Sponge Data Sheet (ESS11M)
Note: ElastaPro also provides sponge silicone rolls instead of pre-cut sheets.
ESS11M Technical Data Sheet
This table* compares AMS3195 values to typical ESS11MM values and indicates the test method.
| Property | AMS-3195 | ESS11MM | Test Method |
| Density, lbs/cu.in. – Under 1⁄4” thick | .025 MAX | .020 | ASTM D1056 |
| Density, lbs/cu.in. – Over 1⁄4” thick | .020 MAX | .018 | ASTM D1056 |
| Compression Deflection,, psi | 6-14 | 11 | ASTM D575 |
| Compression Set, 22 hrs. @ 212°F | 60% MAX | 29 | ASTM D395 |
| Brittle Point, °F | -67 | -103 | ASTM D746 |
| Temperature Range, °F | N/A | -103 TO +450 | ASTM D573 |
| Water Absorption | 5% MAX | PASS | ASTM D471 |
| Tensile Strength, psi | N/A | 100 | ASTM D412 |
| Elongation, % | N/A | 200 | ASTM D412 |
| Thermal Conductivity, BTU in./hr ft 2F | N/A | .6 | ASTM F433 |
| Permittivity | N/A | 1.39 C2/(N·M2) | ASTM D150 |
| Dielectric Strength | N/A | 1.6 KV/mm | ASTM D149 |
| Volume Resistivity | N/A | 10^15 OHM-CM | ASTM D257 |
*These typical physical properties are provided for evaluation information only. It is up to the end-user to determine the appropriate material for the intended application.
Silicone Sponge Sheet Specifications
ElastaPro’s medium-density closed cell silicone materials meet the following specifications
- AMS 3195 for aerospace applications.
- MIL-R-46089 for military gaskets like aerodynamic and rain seals on aircraft and missiles.
- ASTM D1056 for automotive and industrial manufacturing applications.
- MIL-R-6130 for military seals, gaskets, and insulation
What Is Silicone Sponge Sheet?
Silicone sponge sheet is produced using a closed‑cell structure that traps uniform, sealed air pockets throughout the material. This creates a lightweight, compressible elastomer that provides excellent sealing performance with minimal water absorption. Unlike solid silicone, sponge silicone compresses easily under low force, making it ideal for enclosures, doors, access panels, and components that require a soft, conformable seal.
Closed‑Cell vs. Open‑Cell Silicone Sponge
Most silicone sponge used for gasketing is closed‑cell, meaning the internal cells are sealed and resist water absorption. This structure provides:
- Superior environmental sealing
- Low water uptake
- Excellent compression set resistance
- Better long‑term durability outdoors
Open‑cell silicone sponge is softer and more breathable, but it is not typically used for sealing against moisture or dust.
ElastaPro specializes in closed‑cell silicone sponge for industrial, medical, and outdoor applications.
Benefits of Silicone Sponge Sheet
- Closed‑cell structure for reliable environmental sealing
- Lightweight and compressible for low‑force gasketing
- Excellent compression set resistance for long‑term performance
- High‑temperature stability from –60°C to +230°C
- UV, ozone, and weather resistance for outdoor use
- Low water absorption
- Electrical insulation properties
- Available in soft, medium, and firm densities
- Supplied in sheets, rolls, and custom‑cut parts
Common Applications for Silicone Sponge Sheet
Silicone sponge is used across aerospace, electronics, HVAC, industrial, and outdoor sealing environments, including:
- Enclosure and cabinet gaskets
- HVAC door and access panel seals
- Outdoor electrical enclosures
- Thermal insulation pads
- Vibration damping and cushioning
- Aerospace and defense sealing
- LED lighting gaskets
- Medical and laboratory equipment
- Automotive and EV battery gasketing
Closed cell medium density sponge silicone sheet is a versatile material valued across industries for its balance of compressibility, resilience, and durability. Unlike open-cell foams, closed-cell silicone has sealed pockets that resist water absorption, making it suitable for environments where sealing against moisture, air, dust, or chemicals is essential.
With its medium density, the sheet provides a compromise between softness and firmness, enabling reliable sealing and cushioning without excessive compression set. These properties make it a go-to material for engineers and designers who need performance in demanding applications.
Sealing and Gasketing
One of the most common uses of medium density closed cell silicone sheet is in sealing and gasketing. Because the material resists water, UV, ozone, and temperature extremes, it is ideal for both indoor and outdoor applications.
In automotive and aerospace settings, it is cut into gaskets that maintain their integrity under vibration and heat cycling. For enclosures that house electronics, the sheets are die-cut into seals that prevent ingress of dust, water, or electromagnetic interference. The closed-cell structure ensures that when compressed, the seal remains airtight and watertight, protecting sensitive equipment.
Thermal Insulation and Temperature Resistance
Silicone’s inherent resistance to high temperatures and low temperatures expands its application range. Medium density sponge silicone sheets with closed cells can be used as thermal barriers in industrial ovens, HVAC systems, and engine compartments. Their closed-cell construction minimizes heat transfer while maintaining flexibility, making them suitable for gasketing in environments where thermal cycling would cause other materials to fail. The sheets also resist hardening or cracking at low temperatures, making them reliable in cold storage applications.
Vibration Dampening and Cushioning
Another important use for closed cell silicone sheets in medium density is vibration isolation. Medium density sponge silicone absorbs shocks and dampens vibration, extending the life of mechanical assemblies and protecting delicate components. In transportation and heavy machinery, the material serves as a vibration pad or cushion. In electronics, it helps prevent micro-vibrations that could damage circuit boards or optical components. Because the sponge silicone compresses evenly and rebounds reliably, it provides long-term cushioning without losing thickness.
Weatherproofing and Outdoor Applications
Closed cell sponge silicone sheet is widely used in outdoor equipment and architectural applications. For example, it is applied in window seals, skylight gaskets, and door insulation where exposure to sunlight, ozone, and varying weather conditions could degrade lesser materials. Its ability to withstand UV radiation without significant degradation makes it suitable for solar energy systems and outdoor lighting enclosures. Marine applications also benefit from the sheet’s resistance to saltwater, providing reliable seals on vessels and offshore equipment.
Medical and Food Processing Equipment
Because many silicone sponge materials can be formulated to meet FDA or other medical-grade standards such as USP Class VI or ISO 10993, medium density sheets are also applied in healthcare and food environments. They are cut into gaskets for sterilization chambers, seals for peristaltic pumps, and cushioning pads in diagnostic devices. Their closed-cell structure ensures hygienic performance since they do not absorb fluids and are easy to clean. Typically, medical grade silicones are platinum cured.
Available Densities, Thicknesses, and Formats
ElastaPro offers silicone sponge in:
- Densities: Medium
- Thicknesses: Standard and custom
- Sheet sizes: Standard and custom cut
- Continuous rolls: For converters and high‑volume production
- Custom fabrication: Stripping, slitting, die‑cutting, and waterjet cutting
Technical Specifications
This table provides general technical specifications for silicone sponge sheet.
| Property | Typical Value |
| Cell Structure | Closed‑cell |
| Density Options | Medium |
| Temperature Range | –60°C to +230°C |
| Compression Set | Low |
| Water Absorption | Minimal |
| UV/Ozone Resistance | Excellent |
| Formats | Sheets and Rolls |
Silicone Sponge vs. Solid Silicone Sheet
This table compares silicone sponge sheet to solid silicone sheet.
| Property | Silicone Sponge | Solid Silicone |
| Structure | Closed‑cell | Solid |
| Compression | Very soft, compressible | Firm, resilient |
| Water Absorption | Minimal | None |
| Best Use | Low‑force sealing, cushioning | High‑pressure sealing |
| Weight | Lightweight | Heavier |
| Applications | Enclosures, HVAC, outdoor gaskets | Industrial seals, high‑pressure gaskets |
FAQ: Silicone Sponge Sheet
When do you use sponge silicone sheet?
Sponge silicone sheet is best used when a soft, conformable, and environmentally resistant material is needed to create a reliable seal under low compression forces. It’s ideal for enclosures exposed to temperature extremes, UV, or moisture. However, it is less abrasion-resistant and not suited for high mechanical wear situations.
In short, sponge silicone sheet combines the unique properties of silicone elastomers with the versatility of a compressible cellular structure. For engineers, it offers an effective solution for sealing, cushioning, and insulating applications where performance and durability must be balanced with softness and flexibility.
What are the properties of silicone sponge sheet?
Sponge silicone sheet is typically made from silicone rubber compounded with a blowing agent that creates a uniform cell structure during the curing process. Closed-cell sponge silicone has cells that are not interconnected, allowing it to resist water and fluid absorption. Open-cell sponge silicone, on the other hand, has interconnected pores, making it more breathable but less water resistant. Engineers choose between these types based on whether fluid sealing or air permeability is required.
One of the primary advantages of sponge silicone is its wide operating temperature range. Like other silicone elastomers, it typically performs well from –60 °C to 200 °C, depending on formulation. It remains flexible in cold environments and stable at elevated temperatures, making it suitable for harsh or fluctuating thermal conditions. Additionally, sponge silicone offers excellent resistance to ozone, UV exposure, weathering, and many chemicals.
What are the advantages of silicone sponge sheet?
The compressibility of sponge silicone sheet allows it to form reliable seals with relatively low closure forces. This is particularly important in applications involving lightweight plastic or aluminum enclosures that could deform under excessive gasket pressure. The soft structure can compensate for uneven surfaces, tolerance stack-ups, or warped panels without sacrificing sealing integrity.
Sponge silicone also exhibits excellent recovery after compression, maintaining performance over many cycles. This resilience makes it a preferred choice for gasketing in environments where assemblies may be opened and closed repeatedly. Its low density also reduces weight compared to solid silicone, which can be a valuable advantage in aerospace, automotive, and portable electronic designs.
In addition to sealing, sponge silicone provides effective thermal insulation, vibration damping, and acoustic absorption. These properties make it useful in protecting sensitive components from shock, reducing noise transmission, and improving system reliability.
What are some common applications for silicone sponge sheet?
Engineers specify sponge silicone sheet for a variety of applications across industries. It is commonly die-cut or waterjet-cut into gaskets and seals for electrical enclosures, HVAC systems, and outdoor lighting. In transportation and aerospace, it is used to seal access panels, doors, and hatches where flexibility and environmental resistance are critical.
Sponge silicone is also employed in thermal and acoustic management systems, acting as a buffer between vibrating or moving parts. In medical devices, its inertness and softness make it suitable for cushioning and sealing components.
Is most silicone sponge for sealing closed‑cell or open‑cell?
Most silicone sponge used for sealing is closed‑cell, providing excellent moisture and environmental resistance.
What is silicone sponge used for?
It’s commonly used for enclosure gaskets, HVAC seals, outdoor equipment, vibration damping, and thermal insulation.
Is silicone sponge heat resistant?
Yes. Silicone sponge performs reliably from –60°C to +230°C.
Can silicone sponge be used outdoors?
Absolutely. It offers outstanding UV, ozone, and weather resistance.
Is silicone sponge available in rolls?
Yes. ElastaPro supplies silicone sponge in sheets, silicone rolls, and custom‑cut formats.
Request a Quote
ElastaPro manufactures silicone sponge sheets and rolls engineered for sealing, insulation, and gasketing in demanding environments.
Request a quote today to discuss densities, thicknesses, and custom‑cut options for your application.
