Comparing O-Ring Materials
At Ace Seal, we offer a large selection of standard and custom O-rings in a variety of materials. Understanding the differences between these O-ring materials can help you make the best decision for your sealing application needs.
Chemraz vs. Kalrez
Chemraz® O-rings are often used as a cost-effective alternative to Kalrez® O-rings. As perfluoroelastomers, they share many similar traits. However, their properties vary:
- Temperature: Chemraz and Kalrez operate within a temperature range of -20°F to 615°F, although exact tolerances vary by compound.
- Durometer: Various Kalrez compounds can have a high hardness of up to 90 durometer, while standard Chemraz compounds have an average durometer of 70.
- Chemical Resistance: Chemraz is suitable for a larger range of standard chemical processing operations, while Kalrez is better equipped for extreme applications and high-intensity environments.
- Cost: Chemraz is a more affordable FFKM elastomer, while Kalrez is designed for highly specialized applications, increasing its cost.
Chemraz O-rings and Kalrez O-rings can be used for a wide range of industrial applications, including pharmaceuticals, power generation, chemical processing, aerospace, and semiconductor operations.
Kalrez vs. Viton
Kalrez and Viton® are both fluoroelastomers. These synthetic rubbers display excellent durability and performance, but differ in several ways:
- Temperature: Kalrez can withstand temperatures of up to 615°F, while Viton compounds are typically limited to 400°F.
- Chemical Resistance: Viton is resistant to various chemicals as well as flame, heat, oil, and weather. Kalrez has a higher resistance to tougher chemicals, acids, and solvents.
- Service Life: Kalrez is extremely durable and does not require frequent replacement, even in harsh conditions. Viton has a shorter lifespan in corrosive settings.
- Cost: Viton is more widely available and affordable than Kalrez, which is intended for highly specialized industrial uses.
Kalrez O-rings are the better option for highly corrosive applications, while Viton O-rings are available in a variety of compounds and are better suited for standard automotive, aerospace, and manufacturing operations.
Buna-N vs. Viton
Buna-N (Nitrile) and Viton are among the more popular materials for O-rings and sealing purposes. They each offer their own advantages:
- Temperature: Buna-N is effective within a temperature range of -40°F to 250°F, while Viton can withstand temperatures up to 400°F.
- Fuel & Oil Resistance: Both materials resist petroleum oils and fuels, but Viton provides stronger protection against aggressive solvents.
- Environmental Resistance: Buna-N offers limited resistance to ozone, UV, and weathering, while Viton has excellent resistance to outdoor and harsh conditions.
- Cost: Both Buna-N and Viton are widely available and economical, however, as a more durable and versatile material, Viton has a slightly higher cost.
Buna-N O-rings are often used in automotive fuel systems and hydraulic equipment, while Viton O-rings are used for aerospace, chemical processing, and other high-performance sealing operations.
Silicone vs. Fluorosilicone
Silicone and Fluorosilicone are both highly flexible and resilient materials. They share several properties, but maintain unique elements as well:
- Temperature: Silicone and Fluorosilicone maintain their elasticity in a wide temperature range, from -75°F up to 400°F.
- Chemical Resistance: Silicone resists water, ozone, and weathering but degrades quickly in fuel and oil. However, fluorosilicone retains silicone’s weather resistance while offering strong protection against fuels, oils, and solvents.
- Mechanical Properties: Silicone is softer and more pliable than fluorosilicone, which is less flexible but mechanically stronger.
- Cost: Because silicone is widely available, it is a more affordable option than the specialized fluorosilicone.
Silicone O-rings are commonly used in food processing, medical devices, and outdoor sealing. Fluorosilicone O-rings are better suited for aerospace, automotive, and fuel system applications.
Aflas vs. Viton
Both Aflas® and Viton O-rings are durable fluoroelastomers, but they feature different properties:
- Temperature: While both compounds are well suited for temperatures between 14°F and 400°F, Viton performs better in the lower range while Aflas performs better in higher temperatures.
- Chemical Resistance: Aflas and Viton both have excellent resistant to chemicals, ozone, and steam. In addition, Viton is also highly resistant to acid, flame, heat, oil, and weather.
- Wear Resistance: Viton has a significant advantage over Aflas with excellent durability and wear resistance.
- Cost: Viton is widely available in a range of compounds while Aflas is more specialized, making Viton the less expensive option.
Viton O-rings are ideal for automotive, aerospace, and chemical processing plants, while Aflas O-rings are better suited for oil and gas and power generation applications.
Fluorosilicone vs. Viton
Fluorosilicone (FVMQ) and Viton® (FKM) are both fluoroelastomers that offer excellent temperature and chemical performance. However, they differ in flexibility, durability, and cost.
• Temperature: Fluorosilicone performs exceptionally well in cold temperatures, remaining flexible down to –75°F, while Viton provides reliable sealing in high-heat environments up to 400°F.
• Chemical Resistance: Viton exhibits superior resistance to oils, fuels, and many solvents. Fluorosilicone also resists fuels and oils but offers better low-temperature stability than standard silicones.
• Mechanical & Wear Resistance: Viton provides stronger mechanical integrity and abrasion resistance, making it better suited for dynamic sealing. Fluorosilicone performs best in static applications.
• Cost: Fluorosilicone is more specialized and therefore slightly higher in cost. Viton is more readily available and cost-efficient for general industrial use.
• Service Life: Viton offers longer service life in demanding or abrasive environments, while fluorosilicone excels in low-temperature, static applications.
Fluorosilicone O-rings are ideal for aerospace or cold-weather applications, while Viton O-rings are preferred for high-temperature, chemical, and dynamic sealing needs.
Neoprene vs. Chloroprene
Neoprene and Chloroprene are essentially the same base polymer, but variations in formulation can influence their performance and durability.
• Temperature: Both materials perform within a range of –40°F to 250°F, offering good performance in moderate temperature applications.
• Chemical Resistance: They resist refrigerants, water, and weathering, but are not suitable for strong solvents or aromatic hydrocarbons.
• Mechanical & Wear Resistance: Both offer good abrasion and tear strength and resist ozone and UV degradation, making them suitable for outdoor applications.
• Cost: Neoprene is an affordable, general-purpose elastomer, offering excellent value for standard service conditions.
Neoprene and Chloroprene O-rings are widely used for refrigerant systems, outdoor equipment, and applications requiring moderate durability at a low cost.
Fluorocarbon vs. Viton
Fluorocarbon and Viton® both refer to FKM materials, though Viton is a specific, high-performance brand. The differences are mainly in compound formulation and certification.
• Temperature: Both materials perform between –15°F and 437°F, with certain Viton compounds extending slightly beyond that range.
• Chemical Resistance: Both exhibit excellent resistance to oils, fuels, and many chemicals. Viton may outperform generic FKM in more specialized chemical environments.
• Mechanical & Wear Resistance: Viton typically offers higher tensile strength and better compression set performance, ideal for dynamic seals.
• Cost: Generic FKM compounds are slightly more economical than premium Viton grades.
Fluorocarbon O-rings offer excellent general performance, while Viton O-rings are the preferred choice for high-spec, mission-critical applications.
EPDM vs. PTFE
EPDM and PTFE are both highly durable sealing materials, but they serve very different environments.
• Temperature: EPDM withstands –40°F to 300°F, while PTFE can perform from –330°F up to 500°F, offering a far wider thermal range.
• Chemical Resistance: EPDM is excellent for water, steam, and polar fluids, but not for oils or hydrocarbons. PTFE provides near-universal chemical resistance.
• Mechanical & Wear Resistance: EPDM offers flexibility and resilience, while PTFE provides exceptional wear and friction resistance but less elasticity.
• Cost: EPDM is among the most economical O-ring materials; PTFE is more expensive due to its specialty manufacturing process.
• Service Life: In compatible environments, EPDM provides long service life. PTFE offers exceptional longevity when properly installed in static seals.
EPDM O-rings are ideal for water and steam systems, while PTFE O-rings excel in chemically aggressive and high-temperature applications.
FFKM vs. Kalrez
FFKM (Perfluoroelastomer) and Kalrez® are both top-tier sealing materials designed for extreme service conditions. Kalrez is a premium FFKM brand offering specialized formulations for critical industries.
• Temperature: Both materials operate from –20°F up to 615°F, depending on compound.
• Chemical Resistance: FFKM materials offer outstanding chemical resistance; Kalrez compounds extend this protection against strong acids, bases, and solvents.
• Mechanical & Wear Resistance: Both provide excellent resilience under thermal and chemical stress, with Kalrez offering superior performance in rapid gas decompression and plasma environments.
• Service Life: Kalrez offers exceptional durability in the harshest conditions; standard FFKM compounds provide similar longevity at a lower cost for less extreme use.
Kalrez O-rings are ideal for semiconductor, pharmaceutical, and chemical processing applications, while general FFKM O-rings serve well in any high-temperature or corrosive environment.
