Sponge rubber gaskets vs. solid rubber gaskets is a comparison that engineers need to make during seal design and material selection. Both types of rubber gaskets are available in the same compounds, such as EPDM, silicone, and neoprene. They can also be extruded into the same shapes or molded into sheets. In addition, both types of materials support the same gasket fabrication processes.     

Ultimately, the difference between sponge rubber gaskets vs. solid rubber gaskets is all about air. Sponge rubber materials contain interconnected pockets that either hold air or permit its passage. Solid rubber materials do not share this cellular structure. Both types of gasket materials provide sealing and insulation, but sponge rubber provides better cushioning. Solid rubber provides stronger impact resistance.

If you need a custom sealing solution, Elasto Proxy can help you to compare sponge rubber gaskets vs. solid rubber gaskets for your application. Contact us to buy low-to-medium volumes of gaskets or keep reading to learn about the differences between sponge and solid rubber.

Solid Rubber Gaskets

Solid rubber gaskets can be made of soft, medium, or hard rubber. Durometer, a measure of hardness, is a numeric value on the Shore A scale. Lower numbers are softer and higher numbers are harder. For example, the soft rubber in a pencil eraser has a durometer of 40 Shore A. The hard rubber in a hockey puck has a durometer of 90 Shore A.  

In addition to durometer, engineers who are comparing sponge rubber gaskets vs. solid rubber gaskets need to consider density, rigidity, and force distribution. Harder, denser rubber offer greater resistance to abrasion and wear. They are stiffer and less elastic but can withstand applied forces and resist sudden impacts. Solid rubber gaskets also have desirable acoustical properties and can redirect sound waves.      

Applications for solid rubber materials include shock absorbers, bumpers, and the anti-vibration pads for vehicles, equipment, and machinery. With truck bumpers, for example, solid rubber can absorb an impact such as a truck striking a loading dock. For solid rubber gaskets, applications include surface protection and fluid containment.

Sponge Rubber Gaskets

Sponge rubber gaskets also come in different durometers. They’re usually softer but that’s not always the case. If you’re comparing sponge rubber gaskets vs. solid rubber gaskets, remember that a 40-durometer sponge rubber gasket is still harder than a 30-durometer solid rubber gasket. Also, while sponge rubber provides better cushioning, seal failure can occur if the gasket is over-compressed.    

Sponge rubber gaskets are made of materials with either open cells or closed cells. Open-cell sponge rubber contains open and interconnected pockets that permit the passage of fluids (including air) when the gasket is not compressed. Closed-cell sponge rubber contains balloon-like cells that prevent the passage of these substances at low pressures.

Applications for sponge rubber gaskets include cushioning, shock absorption, vibration dampening, weather stripping, and soundproofing. Sponge rubber is also used in thermal insulation. Like solid rubber, sponge rubber is available in materials that can meet standards such has UL 94 for flame resistance. There’s a lot to consider when specifying rubber gaskets, but help is available for buyers and engineers.

Solid Rubber Gaskets vs. Sponge Rubber Gaskets Simplified

Do you need low-to-medium volumes of custom gaskets for applications such as the doors and windows on mobile equipment? Maybe you need help with enclosure sealing on food equipment, generator sets, or industrial machinery instead. Elasto Proxy can help you to get the gaskets that you need and has 30+ years of experience that we can leverage on your behalf. Contact us to get started.

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