Encapsulated O-ring Choices: M-Cor Inc: ENCAP-O-SEAL

Extreme sealing applications require that engineers carefully choose the materials of construction of the Encap-O-Seal, Teflon® encapsulated o-ring. There are numerous considerations and each application has its unique parameters; when our engineering department is asked to assist in the specification of materials, we start by identifying the most important sealing requirements. These are: operating temperatures with ranges, chemical resistance properties, groove construction and purity requirements. An encapsulation material can then be evaluated for application suitability. Contact our engineering department for assistance: engineering@m-cor.com

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All plastics, including Teflon®, are subject to chemical permeation, therefore, in extreme sealing applications, it is important to match the elastomer core material to the application parameters in order to increase seal cycle times.  For extreme sealing, it is a good practice to match chemical resistance properties, mechanical strength at operating temperatures, compression set resistance and cost of an elastomer to application parameters.

The chart below can assist when determining elastomer core material for M-Cor ‘s , ENCAP-O-Seal, Teflon® encapsulated o-ring. The popular choices are Viton Type A (standard material) or equivalents,  Viton GFS , Silicone and EPDM. These elastomers  are available with either a Teflon FEP or Teflon PFA  encapsulation for conversion into encapsulated o-rings, gaskets or sealing devices. For further assistance contact our engineering department: engineering@m-cor.com


All elastomers are available in FDA compliant grades

Common Acids Elastomer Recommendation
Sydrochloric Acid 37% (cold) EPT, GFS, EPDM, Viton B, FEPM
Hydrofluoric Acid (conc) cold EPT, GFS, Viton B
Sulfurous Acid (conc) EPT, GFS, Viton B
Percloric Acid EPT, GFS, Viton B
Nitric Acid (conc) EPT, GFS, Viton B
Hypochlorous Acid EPT, GFS, Viton B
Acetic Acid 30% EPT, GFS, Viton B, EPDM, Silicone
Common Bases Elastomer Recommendation
Ammonia Anhydrous EPT, GFS, EPDM Viton B, FEPM
Sodium Hydroxide EPT, EPDM, FEPM
Potassium Hydroxide EPDM, FEPM
Calcium Hydroxide ALL


Solvents Elastomer Recommendation
MMethyl Ethyl Ketone EPDM
Acetone EPDM
Toluene EPT, GFS, Viton B
Turpentine EPT, GFS,  Viton B
Hexane EPT, GFS, Viton A, Viton B
Benzene EPT, GFS, Viton B


Here is a list of available Teflon encapsulation material:

Teflon® Encapsulated o-ring