EPDM vs Viton: How to Choose Right Material For Your Project

EPDM and Viton are two popular synthetic rubber materials, but they do not perform the same way. The main challenge for you is to choose the material that best matches your production facility needs and budget.

In today’s guide, we will compare EPDM vs Viton in detail. You will see how they are unique in their performance and properties. In the end, you can better understand which substance fits your requirements.

What is EPDM?

EPDM is a synthetic rubber that combines ethylene, propylene and a small amount of diene. That’s why EPDM stands for Ethylene Propylene Diene Monomer. This material works well in outdoor and wet environments.

You can find it in seals, gaskets, hoses, O-rings, automotive cooling systems and other industrial parts. ASTM D1418 classifies EPDM under the M-class rubber group.

EPDM Rubber Types

Sponge / Cellular EPDM: This is a lightweight, porous and compressible foam substance. It comes in closed-cell forms or open-cell forms.

Solid EPDM: It is a non-porous and continuous synthetic rubber. Unlike foam or cellular rubber, solid EPDM has no internal air pockets or foam structure.

Sulfur Cured EPDM: This type of EPDM grade uses sulfur as the cross-linking agent during vulcanization. You can choose this EPDM if you need flexible rubber with good overall performance.

Peroxide Cured EPDM: It is a high performance synthetic rubber which uses organic peroxides instead of sulfur during the vulcanization (curing) process. The peroxide curing process links the polymer chains together to form a strong rubber material.

What is Viton?

Viton is a fluoropolymer elastomer and synthetic rubber made from fluorinated hydrocarbons. It offers excellent resistance to high temperatures and harsh chemicals. This makes it a popular choice for O-rings, seals and other industrial applications.

DuPont basically owns the Viton™ trademark. Viton is also known as FKM. Because of its popularity, people mostly use “Viton” as a general term for FKM seals and O-rings.

Viton Types

Viton A: It is a standard FKM type with around 66% fluorine by weight. It uses a dipolymer structure and offers a balanced combination of fluorine content and polymer properties.

Viton B: This is a high-performance fluoroelastomer terpolymer that contains approximately 68% fluorine. It contains a terpolymer structure, which gives it a higher fluorine level than Viton A.

Viton F: Grade F is a FKM terpolymer with 70% fluorine content. This material offers excellent resistance to aggressive fluids and fuels.

Viton ETP: Viton ETP (also known as Viton Extreme) is a specialized peroxide cured fluoroelastomer. It uses a modified FKM structure to handle aggressive conditions where standard FKM seals may fail.

Difference Between EPDM and Viton

Temperature Resistance

EPDM works well in both hot and cold conditions. It can handle a temperature range between -50°C to more than 150°C.

Viton can handle around -20°C to 210°C. This means EPDM is better for very cold temperatures and FKM is your ideal choice for very high temperatures.

Chemical Resistance

To better understand the difference between EPDM and viton performance with chemicals, we will compare them in this table.

Material Density

Viton (FKM) has a higher density as compared to Ethylene Propylene Diene Monomer. Hence, it is heavier than EPDM. EPDM is available in both solid and sponge forms, but both are generally less dense than Viton.

It means, Viton rubber does not suit vibration isolation because its high density adds weight. In contrast, EPDM works well for vibration isolation parts.

Mechanical Strength & Durability

EPDM offers good toughness and works well for a wide range of tough applications. Viton provides even greater durability and is a better choice if you need a high performance material for extremely demanding service.

For example, manufacturers use viton in aerospace applications. Because these systems require a very high level of durability and cannot afford material failure. In case your application does not require such extreme durability, EPDM still provides plenty of toughness for many industrial and automotive uses.

Physical Properties

The tensile strength of EPDM rubber ranges between 1000 to 3000 psi. Some specialized compounds can reach up to 360% elongation. Peroxide-cured EPDM can achieve compression set values as low as 9% at 212°F (100°C). It generally performs better than sulfur-cured EPDM.

Viton tensile strength is around 1195 to 2238 psi with 179-237% elongation. It offers excellent compression set performance. Values can be as low as 9 to 10% at room temperature and 17 to 20% at 392°F (200°C). It keeps this sealing performance under long term high heat.

Certifications & Compliance

EPDM is widely available in FDA-compliant grades for food and beverage contact under 21 CFR 177.2600. Many EPDM compounds also meet NSF/ANSI 61 for potable water. Moreover, USP Class VI and 3 A Sanitary standards options also support medical and dairy processing applications.

From the perspective of viton, some of its grades meet FDA requirements under 21 CFR 177.2600 for repeated food contact. Common examples include Viton GF-600S and Viton Extreme ETP-600S. NSF and USP Class VI options also exist for pharmaceutical use. But remember, these certifications apply to specific compounds, not every viton grade.

Cost

EPDM is more affordable and works well for die cutting, extrusion and molding. You can produce Viton in these forms too. But its higher cost makes it less economical if you consider material waste.

But Viton can cost you more than EPDM because it is a specialized substance. Your investment for FKM will be worth it if you need extreme durability or high performance in hot conditions.

Applications

EPDM is widely used for:

• Water treatment equipment
• HVAC system seals
• Steam seals
• Automotive weatherstripping
• Roofing membranes
• Electrical enclosure gaskets
• Coolant and water-system seals & hoses
• HVAC gaskets
• Brake-fluid seals
• Cost-sensitive oil-free parts

Viton or FKM is popular for these applications:

• Fuel system O-rings and seals
• Chemical processing gaskets
• High-temperature under-hood components
• Turbocharger components
• Aerospace sealing
• Oil-and-gas sealing
• Aggressive solvent exposed parts
• Sustained high heat parts

EPDM Advantages

• One major benefit of EPDM is its excellent resistance to water and moisture.
• For outdoor use, this material can handle ozone, sunlight, UV rays and weathering very well.
• Another strength is its ability to stay flexible across a wide temperature range.
• If exposed to many acids, alkalis or polar chemicals, EPDM provides good resistance.
• Over time, EPDM rubber can resist aging and keeps its useful properties.
• In electrical applications, this material also offers good insulation properties.
• EPDM generally costs less, which makes it a more economical option.

Limitations: EPDM rubber has limited compatibility with petroleum oils, fuels and non-polar solvents. These fluids can cause EPDM to swell, soften or lose its strength, which can lead to material failure.

List of Viton Benefits

• Viton has excellent resistance to oils, fuels, lubricants, mineral acids and many hydrocarbons.
• If you need high heat resistance qualities in a substance, FKM can maintain its properties at elevated temperatures.
• Its high fluorine content makes the material resist swelling and degradation in harsh fluids.
• Under demanding conditions, viton is able to maintain good mechanical strength and sealing performance.
• This raw material offers excellent resistance to ozone and oxygen.
• Viton also has good compression set resistance, which assists it maintain sealing force over time.
• For harsh industrial environments, viton offers reliable long-term durability.

Weaknesses: Viton (FKM) has limited performance in extreme cold, steam, hot water and some polar chemicals. It can become stiff below about -20°C to -30°C (-4°F to -22°F) and lose flexibility. Steam above 150°C and hot water can cause rapid degradation and seal failure.

Viton vs EPDM: What is Better For Your Business?

If you are a rubber parts supplier or industrial buyer, your selection between FKM and EPDM rubber can affect product life and overall cost. Both have strong properties, but they handle different conditions.

You should select EPDM if:

• You need NSF 61 certification for potable water applications.
• You need outdoor performance with strong UV & ozone resistance.
• The operating temperature stays below 300°F (149°C).
• You need to handle water, water-based chemicals, steam or hot water.
• The fluid contains ketones, alcohols, acids and alkalis.
• You have a limited budget and the fluid remains compatible with EPDM.

Viton is Ideal Choice For This Usage:

• In harsh chemical environments, where strong acids, chlorinated hydrocarbons or chemical solvents are present.
• When failure carries serious costs such as downtime, contamination or safety risks that justify the higher price.
• Petroleum based fluids such as fuels, mineral oils and aromatic hydrocarbons.
• At higher operating temperatures if continuous heat exceeds 250°F (121°C).
• Where low gas and fluid permeability matters, viton can provide a better fit.

Viton vs EPDM Selection By Industry

The best choice between EPDM and viton can also change based on the industry and working environment. This table will help you to pick the suitable raw material option for your production facility.

RONTEIX Manufactures Automotive Hoses From EPDM & Viton

We use EPDM to design these rubber hoses.

• Radiator hoses
• Coolant hoses
• Heater hoses
• Thermostat hoses
• Water pump hoses

RONTEIX production team uses Viton to manufacture the following products.

• Aircraft fuel hoses
• EV battery cooling hose
• Hydraulic hoses
• Chemical hoses
• Oil cooler hoses
• Fuel hoses
• Turbocharger hose

FAQs

Can I use EPDM seals with oils and fuels?

No, EPDM seals are not suitable for petroleum oils, greases, gasoline or diesel. Contact with these fluids can cause EPDM to swell, soften or lose strength. This situation can lead to seal failure as well.

Does Viton degrade in brake fluid?

Standard Viton (FKM) degrades if exposed to glycol-based automotive brake fluids like DOT 3, DOT 4 and DOT 5.1 fluids. These fluids can cause the material to degrade and lose its sealing performance.

Does Viton perform well in cold weather?

No, standard Viton (FKM) does not perform well in very cold conditions. It can become stiff or lose flexibility at low temperatures. However, some specialty grades like Viton GLT, GFLT and ETP offer better flexibility in cool conditions.

Can You use EPDM and Viton seals in the same assembly?

Yes, you can use EPDM and viton (FKM) seals in the same system. But you should keep them in separate areas and expose each seal only to fluids that suit its material.

Conclusion

EPDM and Viton offer different benefits for several working conditions. That’s why RONTEIX uses both materials to manufacture custom rubber hoses for industrial and automotive needs.

We provide EPDM and Viton hoses in multiple sizes, shapes and specifications to match your requirements. Contact our team to discuss your needs and get a suitable solution.