Fluorocarbon (also called FKM or Viton®) is very close to a universal elastomer for use in the o-ring sealing industry. This is due to its broad range of chemical resistances and very good range of operating temperatures combined with ozone, uv, weathering, and gasoline resistances. Additionally, benefits of fluorocarbon o-rings seals have been seen for use as vacuum seals due to its low gas impermeability rating. Fluorocarbon should be avoided in use with low temperature applications or when exposer to hot water, steam, polar solvents, low molecular weight esters and ethers, glycol based brake fluids, or hot hydrofluoric or chlorosulfonic acids are a factor. The fluorocarbon black AS207-75F o-ring can be reference in one of four ways:
The final consideration for an o-ring after size and material type is the durometer. Durometer is an industry standard measurement for a material’s hardness. Most often for rubber seals, durometer is measured and listed in accordance with the “Shore A” scale. Typical durometers for standard rubber seals are 70, 75 and 90, depending on the material. A higher number indicates a harder material. Durometer is also generally stated and accepted with a “+/- 5” tolerance. For fluorocarbon o-rings, the standard nominal durometer is 75.
O-Rings, rubber seals and custom molded rubber components for:
AS568-207 (Durometer 75) cross reference sizes
