Surface treatment of o-rings with lubricants helps to protect against abrasion, pinching, or cutting during installation in parts assembly. External lubrication helps seat the o-rings into grooves with minimum twisting and maximum assembly speed. Parylene, Teflon™ and silicone are great choices for external lubricants.
In hydraulic systems where lubricating fluids are nearly always present, surface treatment of o-rings is less essential.
In pneumatic or vacuum applications where system fluids are predominantly absent, o-ring surface lubrication is mandatory for effective, low friction operation and the prevention of seal leakage. o-ring surface lubricants help prevent leakage from around the seal by filling the micropores of both the o-ring and surrounding metal surfaces.
A final benefit of o-ring lubrication is the protection it offers some elastomers from the degrading effects of exposure to oxygen and ozone. In this regard, o-ring surface lubrication acts as a barrier, helping to prevent premature seal aging and extending o-ring service life.
Precautionary Note: In all cases requiring o-ring lubrication, make certain to select a lubricant that is compatible with both the o-ring compound and the system chemicals being used. The lubricant, or additive which it contains, should not cause excessive shrinkage or swelling of the o-ring compound.
Also, check the recommended temperature range for the lubricant of choice, making certain to operate within stated limits.
Finally, if system filtration is being employed, check to see that the lubricant is capable of passing through filters prior to use with the system o-rings.
As a general guide, our O-Ring Lubricant Guide lists a number of lubricants used with specific o-ring compounds, in the application shown.