Viton® and Kalrez® Composition O-Rings

Viton - By Size

Viton - 0

Kalrez - By Size

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For background information, see O-Rings.

O-Rings are available in five different materials from Scientific Instrument Services. Each type has its advantages and disadvantages as listed in the O Ring Comparison Chart. Of the various types of O-Rings available from SIS, Viton® is the most popular for mass spectrometers and other laboratory instruments. This is due to Viton®'s high temperature stability and good resistance to chemicals and ozone. Kalrez® has the same advantages as Viton® but it has greater chemical and temperature resistance. However Kalrez® is considerably more expensive than Viton®. As a class both Viton® and Kalrez® are known as Fluorocarbon Rubber (FKM) type O-rings.

Commercial Trade names for FLUOROCARBON RUBBER (FKM) type O rings

Viton® * E.I. dupont de Nemours Company
Fluorel * 3M
Kalrez® (high temp) * E.I. dupont de Nemours Company
Kel-F * 3M (formerly Kellogg)

Viton® or fluorocarbon elastomers were first introduced in the mid 1950's. Since then they have become of major importance in the seal industry. Due to its good chemical resistance, high temperature range and its low compression set, fluorocarbon rubber is the most significant single elastomer development in recent history. The working temperature range ifor Viton® is considered to be -15 to +400 degrees F (-29 to +204 degrees C), but it will take temperatures up to 600 degrees F (316 degrees C) for short periods of time. Du Pont's Kalrez® is normally recommended up to 500 degrees F (260 degrees C). On the low end, Viton® compounds have been known to seal at -65 degrees F (-54 degrees C) in some special static applications, however the normal low temperature limit is -15 degrees F (-26 degrees C). Fluorocarbon 0-rings should be considered for seal use in aircraft, automobile, scientific instruments and other mechanical devices requiring maximum resistance to elevated temperature and to many functional fluids. They are widely used in diffusion pumps on vacuum systems and on vacuum flanges on mass spectrometers and electron microscopes. Viton® is recommended for most applications and Kalrez® is only used where the additional temperature range can be justified by the increased cost.

Viton® and Kalrez® are recommended for:

Petroleum oils. Di-ester base lubricants (MIL-L-7808, MIL-L-6085).
Silicate ester base lubricants (MLO 8200, MLO 8515, OS-45.)
Silicone fluids and greases.
Halogenated hydrocarbons (carbon tetrachloride, trichloroethylene).
Selected phosphate ester fluids. Acids.

FKM is not recommended for:

Ketones (MEK, acetone). Skydrol fluids.
Amines (UDMH), anhydrous ammonia.
Low molecular weight esters and ethers.
Hot hydrofluoric or chlorosulfonic acids.

O-Rings are available in sizes (sizes 0, 1, 2 and 3) which correspond to the diameter of the cross section of the O-Ring. Within these groups the O-Rings are classified according to their inside diameter. To see a complete selection of the various sizes and types of O-Rings available from Scientific Instrument Services, just click on the hyperlink on the size list above. If the size you require is not listed, it may still be available. Contact us with your requirements.

Kalrez® and Viton® are registered trademarks of E. I. DuPont de Nemours