Crush Washers | McMaster-Carr
Also known as crush washers, these compress when tightened to form a tighter, more durable seal than rubber washers. They are commonly used to seal fluids such as oil and fuel. Washers are not reusable.. Copper washers are corrosion resistant in wet environments, nonmagnetic, and electrically conductive.. Aluminum washers are lightweight and corrosion resistant in wet environments.