O-Ring Material Comparison: NBR, EPDM, FKM(Viton), Silicone Selection Guide
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Choosing the correct O-ring material is critical to avoid premature seal failure. Below is a side-by-side comparison of the four most popular industrial elastomers: NBR (Nitrile), EPDM, FKM (Viton), and Silicone (VMQ).
Temperature: -40°C ~ +120°C
✅ Pros: Excellent oil, fuel and hydraulic fluid resistance, good abrasion, low cost, most widely used general-purpose O-ring.
❌ Cons: Poor resistance to ozone, UV sunlight, hot steam and outdoor weathering. Long-term outdoor sun exposure will cause cracking and hardening.
👉 Best for: Hydraulic systems, automotive oil circuits, pneumatic tools, general machinery oil sealing. Not recommended for outdoor UV-exposed applications.
EPDM / Ethylene Propylene Rubber
Temperature: -50°C ~ +150°C
✅ Pros: Outstanding resistance to hot water, steam, ozone and UV ultraviolet rays. It ages slowly under outdoor sunlight, also works well with dilute acids and coolants.
❌ Cons: Not compatible with mineral oil, gasoline and petroleum fuels.
👉 Best for: Water valves, cooling systems, outdoor equipment, water treatment, brake fluid sealing. Top pick for outdoor UV environments.
Temperature: -20°C ~ +200°C
✅ Pros: Premium heat, fuel, oil, ozone and UV resistance. It can withstand strong ultraviolet radiation and harsh chemical environments with long service life.
❌ Cons: Higher cost, not suitable for hot steam.
👉 Best for: High-temperature engines, chemical equipment, fuel systems, automotive exhaust, aggressive chemical sealing. Great for outdoor chemical & UV conditions.
Silicone / VMQ
Temperature: -60°C ~ +200°C
✅ Pros: Ultra-wide temperature range, excellent ozone and UV resistance. Available in food-grade formula. The silicone O-ring is soft, smooth and flexible to touch. Our physical silicone O-rings show a semi-transparent or milky white appearance, they remain elastic after long sun exposure, ideal for static sealing scenarios.
❌ Cons: Poor oil & fuel resistance, low tear strength, not ideal for dynamic heavy friction.
👉 Best for: Static seals, food & beverage equipment, oven, sensor, low-pressure high/low temperature sealing.
Quick Selection Tip
If your working environment has mineral oil or hydraulic fluid and you want cost savings, choose NBR.
For hot water, steam and outdoor sun exposure, EPDM is your best option.
Pick FKM (Viton) when you need high temperature resistance, fuel or chemical corrosion protection under UV.
Use silicone O-rings for food-grade use or static seals under extreme high / low temperature and ultraviolet light.
We supply standard AS568 / ISO / JIS O-rings in NBR, EPDM, FKM and Silicone. Custom sizes & hardness available. Contact us for your sealing project.