Rubber materials are used because of their high flexibility, pliability, and conformability to different surfaces.

Different rubber washer materials benefit different applications. While rubber washers can be manufactured in a wide variety of materials, most applications use the following washer compositions:

Silicone rubber washers: Silicone washers withstand extreme temperatures  (̶ 150° to 500°F) in dry or humid climates, offering the best overall temperature range available. They also operate with low compression sets and resist ozone, UV light, and fungus. Silicone is the material of choice for brake fluids and high aniline point oils, but it doesn’t work well for petroleum oils and ketones.

Ethylene propylene diene monomer (EPDM) rubber washers : These washers can withstand weather extremes and temperatures from ̶60° to 280°F. They also offer low gas permeability and resist ozone, steam, water, alcohols, and brake fluids. EPDM rubber washers have dielectric qualities, which provide excellent protection from electrical currents, ozone, and sunlight. It is heat resistant and has excellent color stability.

Neoprene rubber washers : These washers weather well, have high ozone resistance, and good oil, petroleum, and solvent resistance. They operate in temperatures ranging from ̶65°F to 260°F. They also resist freons, high–aniline point oils, and mild acids. Neoprene rubber works well in general-purpose elastomer applications.

You can buy stock sealing washers in small and large quantities, but it’s also possible to custom-design washers to your precise specifications.