Extreme material softness/compressibility often calls for an open cell gasket material. An open cell structure lets fluid pass through easily and lets the material compress down to a fraction of its free height. The cells can also hold liquid, hence the material often being called sponge or foam. However, this behavior means open cell sponge can’t be used for sealing against liquids.
Elastomers: Natural Rubber, Neoprene, EPDM, Nitrile, SBR Red Rubber
Durometer: 50 – 80 Shore OO
Thickness: .040” to 1”
Width: 48” (can be cut to your specifications)
Open cell sponge material can be made from a number of elastomeric polymers. Natural rubber, neoprene and EPDM are the most common, although it is also available in nitrile and SBR. Chemical resistance and working temperature derive from those base materials. What all open cell sponge has in common though is softness. Shore OO durometer values are from 50 to 80. (The ‘OO’ scale is the softest.)
Applications for open cell sponge include cushioning, impact absorption, gasketing and gap-filling. For example, it’s sometimes used to stop surfaces touching or banging, and also as a lightweight material for taking up gaps in assemblies. Open cell gasket material naturally has a high coefficient of friction, and low-slip grades are available that improve on this. It’s also available in electrostatically dissipative (ESD) grades for use with electronics and in electronic assembly operations.Open cell sponge is mostly black, although some natural rubber formulations are available in tan/brown. Hennig Gasket & Seal sells it in both sheet and roll form, and it’s available in thicknesses from 0.040” to 1”.