Crushed cellular foam, or semi-closed cell, was developed to solve the frustrating problem of sealing flexible or uneven substrates. Normal cellular materials will not conform to highly irregular surfaces and different materials can often flex due to stress or temperature, causing a leak. Automobiles would often develop leaks when summer rainstorms would rapidly cool the hot sheet metal body, causing expensive water damage. Manufacturers decided to develop a foam that would conform like an open cell, but still make a watertight seal.
Crushed cellular is exactly that: a closed cellular foam is manufactured, then it is run through a roller to crush or rupture the individual cells. What is left is a cell that is mostly enclosed, but air can go in and out of the small ruptures in the cell walls. This allows the foam to be highly conformable, but still capable of sealing against water.
Working with crushed cellular can be challenging. It isn’t a cure-all. Careful testing needs to be performed by the designer to verify that water will not infiltrate their design and therefore the gasket thickness may need to be tweaked several times before a perfect fit is obtained.
Atlantic Gasket offers two crushed cellular products: Ensolite EFO, an EPDM based product, and SFO, made from PVC/Nitrile polymers. Atlantic Gasket can laminate, slit to width, die-cut or water jet cut these materials to your specific requirements.