Understanding Sealing Material Differences
When selecting the right material for your sealing application, the choice between FKM, Viton, and silicone can significantly impact performance, cost, and longevity. This guide breaks down the key differences to help you make an informed decision for your OEM or ODM manufacturing project.
What is FKM (Fluoroelastomer)?
FKM is a family of fluoroelastomers known for excellent resistance to heat, oil, fuels, and chemicals. Originally developed for aerospace applications, FKM has become the go-to material for demanding industrial sealing environments.
- Temperature range: -26C to +205C (some grades up to +250C)
- Oil resistance: Excellent in mineral oils, fuels, and lubricants
- Chemical resistance: Outstanding against acids, aldehydes, and most petroleum oils
- Limitations: Poor performance in ketones, esters, and some amines
What is Viton?
Viton is a brand name owned by Chemours for a specific type of FKM. When people say "Viton seal," they are typically referring to FKM fluoroelastomer O-rings and seals. Viton offers the same performance characteristics as standard FKM at a slightly higher price point due to the brand premium.
What is Silicone?
Silicone (VMQ - Vinyl Methyl Silicone) is an inorganic elastomer with exceptional temperature resistance and flexibility. Unlike carbon-based rubber, silicone offers superior performance in extreme temperatures and food-grade applications without the oil compatibility trade-offs.
- Temperature range: -60C to +230C (special grades to +280C)
- Flexibility: Excellent compression set resistance at high temperatures
- Food safety: FDA-compliant grades available for food processing equipment
- Limitations: Poor tear strength, not suitable for dynamic fuel contact
Material Comparison Table
The table below summarizes key property differences between FKM/Viton, silicone, and EPDM rubber to guide your material selection process.
| Property | FKM / Viton | Silicone | EPDM |
|---|
| Max Temperature | +205C to +250C | +230C | +150C |
| Min Temperature | -26C | -60C | -45C |
| Oil Resistance | Excellent | Poor | Poor |
| Chemical Resistance | Excellent | Good | Good |
| Weather Resistance | Excellent | Excellent | Excellent |
| Food Grade Options | Limited | Yes (FDA) | Yes |
| Cost Level | High | Medium-High | Low |
| Best For | Fuel, chemicals, oil | Food, medical, high heat | Water, steam, outdoor |
How to Choose: Decision Guide
Choose FKM or Viton if: Your application involves petroleum oils, fuels, lubricants, or chemicals at temperatures up to 205C. Automotive fuel systems, chemical processing plants, and aerospace applications are ideal for FKM.
Choose Silicone if: You need food-grade compliance, medical device compatibility, or superior performance in extreme cold environments where oil contact is not a primary concern.
Choose EPDM if: Your application involves water, steam, or outdoor weathering. EPDM is the cost-effective choice for non-oil-contact sealing in automotive cooling systems, plumbing, and construction.
Why Work with AnlinTech for Your Sealing Materials?
As a professional custom rubber and silicone parts manufacturer, AnlinTech helps B2B customers select the optimal sealing material for their specific applications. Our engineering team provides free material selection consultation and can produce samples for your testing.
Contact AnlinTech today for a free material recommendation based on your application requirements, operating conditions, and cost targets.
