Product Spotlight

What are Fluorosilicone O-Rings? A Simple Guide to Fluorosilicone Seals


Fluorosilicone, also referred to as FVMQ, is a premium elastomer that is commonly applied in the aerospace industry. Popular trade names for fluorosilicone include FE, Elastosil, Silastic FSR and FSE. 

Similar to silicone, fluorosilicone offers excellent stability in extreme temperatures while also offering the chemical resistance properties found in fluorocarbons. These benefits, among others, make fluorosilicone o-rings and seals an optimal choice for a variety of critical applications. 

Mechanical Benefits

Fluorosilicone seals are well suited for both high and low temperature environments with a working temperature range of -75°F to +400°F. Other important characteristics include:

  • Resistance to fuel, oil and solvents
  • Good compression set and resilience properties
  • Excellent resistance to air, sunlight and ozone
  • Suitable for exposure to chlorinated and aromatic hydrocarbons
  • Recommended for use with petroleum oil, jet fuel and mineral oils

While oil and fuel resistance makes fluorosilicone an excellent choice for the aerospace industry, fluorosilicone is becoming an increasingly popular material for a wider range of sealing applications.


Fluorosilicone possesses a few limitations that make it unsuitable for specific environments. These limitations include: 

  • Poor abrasion resistance
  • Limited physical strength
  • High friction characteristics

Based on these limitations, fluorosilicone is recommended for static applications only, not dynamic. Additionally, fluorosilicone is not chemically compatible with brake fluids, hydrazine, or ketones and therefore should not be exposed.

Common Applications

Fluorosilicone is used in a variety of applications in the aerospace and automotive industries. These applications include:

  • Engine gaskets
  • Electrical housing seals
  • Aerospace fuel systems
  • Automotive fuel emission control systems
  • Fuel pumps and tank seals
  • Low outgassing applications

Aerospace military specifications require fluorosilicone to display high modulus and increased temperature resistance in o-rings, molded parts and extruded shapes. Under pressure, fluorosilicone retains its shape and quickly bounces back after compression, which are both important qualities for aerospace applications.


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