Commonly available backing materials for bonded sealing washers include: steel, 18-8 stainless steel, 316 stainless steel, silicon bronze, and copper. Typically EPDM (often called neoprene, but that is a different material altogether)  is the material used for the sealing part. Ethylene Propylene Diene Terpolymer is an excellent, low-cost ozone and weather resistant elastomer which possesses superior aging characteristics. These washers seal a hole against intrusion of the elements when used properly.

Correct Installation
The washer is tight against surface and the seal flows inward to seal minor fastener diameter and surface voids. The washer curves neither up nor down. It lies almost perfectly flat.

Talk to Hardware Everywhere’s knowledgeable customer service team for help choosing the fasteners that match your application. Call us at 1-800-432-8979 or contact us online.