The most common sponge gasket is a closed-cell rubber blend material. This material is reasonably resilient, has moderately good recovery, and is inexpensive. It can be provided plain, or with a pressure-sensitive adhesive on one side. Closed-cell sponges are available in a variety of elastomers for a wide range of applications. These materials work well in many situations, particularly those that have a constant squeeze on the gasket material.
Applications with alternating squeeze, such as doors that open and close, will benefit from using microcellular urethanes as gaskets. These materials exhibit almost zero compression set, have superior recovery, and are well suited for gaskets that have variable loads. They are particularly useful for electrical boxes and enclosures, and are available in UL listed grades for such applications. These materials, while somewhat more costly, out-perform typical closed-cell blended sponges where a seal must be maintained under imperfect seating conditions. They, too, can be provided plain or with a pressure-sensitive adhesive backing.
We stock a variety of sponge gasket materials, including Poron® and Griswold microcellular urethanes. Please contact us to discuss your application and be provided with a cost-effective solution for your sealing problem.