Material
Fluorosilicone (FVMQ) O-Ring Guide
Fluorosilicone properties for fuel and low-temperature service.
Polymer
Fluorosilicone (FVMQ)
Temperature range
−55 °C … +175 °C
Hardness
40–80 Shore A
Overview
Fluorosilicone combines silicone's excellent low-temperature flexibility with fuel and mineral-oil resistance that ordinary silicone lacks. It is the standard choice for aircraft fuel systems and cold-climate fuel sealing, but it shares silicone's low mechanical strength.
Strengths
- • Excellent low-temperature flexibility to about −55 °C
- • Resists aircraft fuels and mineral oils, unlike VMQ
- • Good ozone and weather resistance
- • Wide service temperature for a fuel-resistant elastomer
Limitations
- • Low mechanical strength — static service preferred
- • Significantly more expensive than VMQ or NBR
- • Poor with brake fluid, ketones and hot water/steam
- • Allowable extrusion gap must be reduced to 40 % of the chart value
Compatible media
Aircraft and hydrocarbon fuelsMineral oilsLow-temperature serviceOzone & weathering
Media to avoid
Glycol brake fluidKetones & estersHot water & steamAbrasive dynamic duty
Typical applications
Aerospace fuel systemsCold-climate fuel and oil sealsAircraft and defence static jointsWide-temperature fuel-contact sealing
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