Silicone Products Silicone Sponge Sheets

What Are BELLOFOAM™ Silicone Sponge Sheets?

BELLOFOAM™ silicone sponge sheets are lightweight, closed-cell silicone sponge materials engineered for sealing, gasketing, cushioning, insulation, and environmental protection in demanding applications. Their closed-cell construction helps resist moisture absorption and wicking while providing the flexibility, compression recovery, and temperature stability expected from high-performance silicone materials.

Bellofram Elastomers manufactures BELLOFOAM™ silicone sponge sheeting in multiple densities, thicknesses, and specialty formulations to support applications ranging from general-purpose environmental sealing to flame-retardant and fuel-resistant requirements.

Key Takeaways

• BELLOFOAM™ is a closed-cell silicone sponge sheet material designed for sealing, cushioning, and insulation.
• Closed-cell construction helps prevent moisture wicking and supports reliable environmental sealing.
• BELLOFOAM™ provides lightweight performance with low closure force and strong compression recovery.
• Multiple densities and specialty formulations are available.
• Select grades meet requirements including UL 94 V-0, AMS 3323, AMS 3195, and BMS 1-23.
• Sheet thicknesses are available up to 2 inches on many BELLOFOAM™ grades without lamination.
• Value-added options include pressure-sensitive adhesive (PSA) and custom flash-cut finished shapes.
• Common applications include aerospace, electronics, transportation, industrial equipment, and environmental sealing.
• Manufactured in the USA.

Why Choose Closed-Cell Silicone Sponge Sheets?

Closed-cell silicone sponge combines the environmental resistance of silicone with a cellular structure designed to provide lightweight compression sealing.

Unlike open-cell materials that can absorb or wick moisture, BELLOFOAM™ is engineered as a truly closed-cell silicone sponge. This makes it particularly valuable for applications where water resistance, compression recovery, thermal stability, and long-term sealing performance are critical.

Benefits of BELLOFOAM™ Closed-Cell Silicone Sponge Sheets

BENEFIT	WHY IT MATTERS
Closed-Cell Construction	Helps prevent moisture absorption and wicking in environmental sealing applications.
Lightweight Performance	Provides sealing and cushioning without adding unnecessary weight to the assembly.
Low Closure Force	Allows the material to compress and form a seal without requiring excessive clamping force.
Compression Recovery	Helps the material rebound after prolonged compression and maintain sealing integrity over time.
Temperature Stability	Silicone construction supports reliable performance across demanding hot and cold environments.
UV and Ozone Resistance	Supports long-term performance in outdoor and environmentally exposed applications.
Specialty Formulations	Flame-retardant, fluorosilicone, and aerospace-qualified options are available for specialized requirements.

BELLOFOAM™ Silicone Sponge Sheet Options

Bellofram Elastomers offers multiple BELLOFOAM™ grades to address different compression, density, flame resistance, chemical resistance, and aerospace requirements.

Different applications require different material characteristics, as well, which is why BELLOFOAM™ is available in both general-purpose and specialty formulations.

Depending on the grade selected, available specifications and performance options include:

• ASTM D1056 closed-cell silicone sponge classifications
• UL 94 flame-retardant options
• AMS 3323 fluorosilicone sponge
• AMS 3195
• Boeing BMS 1-23
• Other application-specific requirements

For applications where flame resistance is a priority, Bellofram offers BELLOFOAM™ grades specifically developed for enhanced flammability performance, including UL-rated options.

For applications exposed to fuel, oil, or aggressive fluids, fluorosilicone grades such as BELLOFOAM™ 7748 provide an alternative to standard silicone sponge.

For complete physical properties, test data, specifications, and individual product data sheets, view the BELLOFOAM™ Silicone Sponge Sheets Brochure.

Silicone Sponge Sheets vs. Solid Silicone Sheets

The primary difference between silicone sponge and solid silicone sheet is material structure. Silicone sponge contains a closed-cell structure that makes the material lighter and more compressible, while solid silicone provides a denser, non-cellular construction.

Silicone Sponge Sheets vs. Solid Silicone Sheets

FEATURE	SILICONE SPONGE SHEETS	SOLID SILICONE SHEETS
Construction	Closed-cell silicone structure.	Dense, non-cellular silicone rubber.
Density	Lightweight.	Heavier and denser.
Compression	Highly compressible with relatively low closure force.	Less compressible and typically requires greater force to deform.
Typical Priority	Environmental sealing, cushioning, insulation, and gap filling.	Durability, strength, and dense rubber sealing.
Common Applications	Gaskets, enclosure seals, cushioning, vibration isolation, thermal barriers.	Dense gaskets, seals, pads, barriers, and industrial components.

For applications requiring dense, non-cellular material, explore our solid silicone sheets.

Common Applications for Silicone Sponge Sheets

BELLOFOAM™ silicone sponge sheets are used in applications requiring flexible compression sealing, insulation, cushioning, or protection from environmental exposure.

Common Applications for BELLOFOAM™ Silicone Sponge Sheets

APPLICATION	HOW SILICONE SPONGE HELPS
Environmental Sealing	Closed-cell construction helps protect equipment from moisture and environmental exposure.
Gaskets	Compressible material conforms to mating surfaces to provide dependable sealing with relatively low closure force.
Thermal Insulation	Silicone construction provides thermal stability for components exposed to demanding temperature conditions.
Vibration Isolation	Compressible sponge construction helps cushion equipment and reduce transmitted vibration.
Electrical and Electronic Enclosures	Provides lightweight sealing around sensitive components exposed to moisture, dust, or temperature changes.
Transportation and Aerospace	Provides lightweight sealing and cushioning where environmental resistance and weight reduction are important.
Industrial Equipment	Supports gasketing, cushioning, insulation, and environmental protection in demanding machinery and assemblies.

Value-Added Silicone Sponge Sheet Capabilities

Bellofram Elastomers can supply BELLOFOAM™ as sheet material or further process the material into application-ready components.

Available value-added options include:

• Pressure-sensitive adhesive (PSA) on one or both sides
• Custom flash-cut gaskets and finished shapes
• Precision skiving to required thicknesses
• Custom sheet and component configurations
• Material selection support based on compression, temperature, environmental, flame, or chemical requirements

Our in-house skiving capabilities allow BELLOFOAM™ buns to be converted into precise, rind-free sheet material while maintaining control over thickness and finished quality.

For custom shapes, gaskets, and prototype components manufactured without dedicated tooling, check out our Flash Cut Silicone capabilities.

When Should You Choose Closed-Cell Silicone Sponge?

A closed-cell silicone sponge sheet may be the right choice when your application requires a lightweight and compressible seal that can continue performing under demanding environmental conditions.

BELLOFOAM™ may be ideal when:

• Low closure force is important.
• Moisture absorption or wicking must be minimized.
• The application requires repeated compression and recovery.
• Weight reduction is important.
• The material will be exposed to UV, ozone, weather, or temperature extremes.
• Thick silicone sponge is required without laminating multiple layers.
• Flame-retardant performance is required.
• Fuel- or oil-resistant fluorosilicone sponge is needed.
• Custom adhesive-backed or flash-cut components are required.

Why Choose Bellofram Elastomers for Silicone Sponge Sheets?

Bellofram Elastomers combines silicone material expertise with in-house manufacturing, skiving, and fabrication capabilities to provide both bulk BELLOFOAM™ sheeting and application-ready silicone sponge components.

Bellofram Elastomers offers:

• Multiple BELLOFOAM™ densities and specialty formulations.
• Closed-cell silicone sponge designed to minimize moisture wicking.
• Lightweight, low-closure-force materials.
• Thicknesses up to 2 inches on many grades without lamination.
• UL-rated flame-retardant silicone sponge options.
• Fluorosilicone options for fuel and oil resistance.
• Aerospace-qualified material options.
• Pressure-sensitive adhesive capabilities.
• Flash-cut finished gaskets and custom shapes.
• U.S.-based manufacturing and technical support.

View the complete BELLOFOAM™ Silicone Sponge Sheets Brochure to compare available grades, specifications, physical properties, and value-added options.

Frequently Asked Questions About Silicone Sponge Sheets