Silicone Sponge Gasket, Waterjet Cut

Expanded rubber has become a very popular product in the gasket industry. We are often asked for requests that use silicone sponge, which is closed cell only. Silicone foam is available in different cell structures, such as modified closed, closed, open, etc. There are many advantages to utilizing silicone sponge in various applications, including gasketing, cushioning, vibration dampening, enclosure sealing, and water sealing. NEDC mainly manufactures silicone sponge gaskets.

What is Silicone Sponge?

Silicone sponge is basically expanded silicone rubber. It is made from silicone sponge playdo, and heated up to make cells that create a “silicone sponge.” It is able to offer many of the same properties of silicone rubber. Some of these properties include ozone and UV resistance, temperature resistance, and low compression set. The compressibility of these materials is impressive; it easily allows closure to happen without extremely high pressure.

Another well-known property of silicone sponge is its feasibility of meeting UL 94 requirements such as V0 and below. The closed cell structure of the sponge is important under the pressure of water. These closed-off cells prevent the water from intruding into the aggregate structure of the sponge and keep the integrity of the seal against water. There is some contention on what exactly closed-cell sponge/foam is, but usually less or equal to 5% absorption is a good rule of thumb. These closed cells play a large part in the density of the material. For this reason, Silicone Sponge is also used for IP66, and IP67 applications for sealing enclosure applications.

Applications for Silicone Sponge Gasketing/Cushions

Extreme Temperatures- Whether its outside up in Alaska, or its in the high heat, silicone sponge can deal with a wide operating temperature, typically -100°F to 500°F. I’ve seen them used in cryogenic applications, and for furnace applications as well.

Compression Set Resistance- Silicone Sponge highest compression set is normally 15%, however it can be even lower depending on which gasketing material chosen. For example R10480S Silicone Sponge is a low-compression set material with a typical compression set of 5%.

Outdoor Gasketing- Silicone Sponge is a good use for anything outdoor gasketing. Due to all of the benefits mentioned above- it nearly always makes a good outdoor gasket.

FDA Requirements- Many customers require the FDA 21 CFR 177.2600 for their products. These require ingredients that are compliant to the specification to be included in the material when its manufactured. These can include fillers, peroxides, and other additives.

Why Pick Silicone Sponge Gasketing over other Cellular Sponges?

We outlined some reasons above why you may want to chose silicone sponge. However, if you boiled silicone sponge down to two reasons, it would be boil down to

1. The temperature range of silicone sponge.

2. The strength of the elastomer coupled with its low compression force. With other organic elastomer sponges you may encounter, silicone sponge is easily the strongest.

Densities/Specifications Available

It is well known that silicone sponge comes in a variety of densities, which range from Extra Soft to Extra Firm. The density and firmness play an (per ASTM D1056 0-3 psi for extra soft, extra-firm is ASTM D1056 16-24 psi) integral role in how well the gasket compresses, and how well the gasket absorbs shock/impact.  Silicone sponge has a lot of different specifications that may be applicable in a given situation, such as MIL-STD-670 TE12, AMS 3195(medium), AMS 3196(firm), ASTM D6576, MIL­R­6130, MIL-R-46089, ASTM D1056, 2D1, 2D2, 2D3/2D2/2D4, 2D5 and others.

UL Ratings of Silicone Sponge Products

Finding commercially available sealing/cushion products that are UL rated can be a challenge. One thing with silicone sponge/foam products is that there is a wide availability including:

UL-50E gasketing/sealing for electrical enclosures

UL94 HBF gasketing for flame retardant applications (R10460 Silicone Sponge UL94 HBF),

UL94 V0 gasketing for flame retardant applications (R10400 Silicone Sponge)

UL1570, UL1571, UL 1572(R10460 Silicone Sponge)

Different types of Silicone Sponge Gasketing

-Flame Retardant Silicone Sponge such as R10400, or R10460 Sponge from Saint Gobain

-Fuel Resistant/Fluid Resistant Fluorosilicone Sponge or Fluorinated Sponge Sheeting

-Fiberglass Reinforced Silicone Sponge such as R10450 Silicone Sponge Sheeting

-Thermally Conductive Silicone Sponge

silicone sponge gaskets app, missile applications

Other Availability of Silicone Sponge

The availability of silicone sponge material is virtually ubiquitous, with it being present industry wide. Most silicone sponges are provided with a textured fabric finish but may vary depending on part geometry and other variables. Although the natural rusty red is the typical color for silicone sponge, other colors are available upon request, such as grey, black, brown, blue, and white. There are many thicknesses of silicone sponge available, ranging from .032″ to 2.0″ thick.

Standard Silicone Sponge Products

More Information/Cutting of Silicone Sponge

NEDC regularly converts silicone sponge products into custom gaskets, and cushions through die cutting, and waterjet cutting. Silicone tape or Acrylic tape is available with these materials. Finally, silicone sponge extrusions can be supplied by NEDC at cut-to lengths, or in plain cord stock. Lastly, fluorinated silicone sponge is available as well. For more information concerning silicone sponge products or gaskets/seals made of silicone sponge please contact sales@nedc.com.