To make effective vacuum seals, o-rings must be comprised of elastomeric materials featuring low gas permeability, low weight loss under vacuum, and good compression set characteristics.

Best Choice

Fluorocarbon offers good to excellent resistance to gas permeation and low-weight loss in vacuum applications.

As an added measure of leak prevention, lubrication of o-rings with vacuum grease helps to fill the microscopic pores of surrounding glandular surfaces which have been machined to the recommended 16 to 32 RMS finish.