EPDM is one of the most widely used elastomers for custom rubber extrusions, particularly when a component needs to withstand outdoor weather, ozone, water, UV exposure, and changing environmental conditions.
From weather seals and construction products to transportation components and industrial equipment, EPDM rubber extrusions can provide a durable and flexible solution for demanding applications.
However, EPDM isn’t the right material for every environment. Understanding its strengths and limitations is important before specifying it for a custom component.
Northwest Rubber Extruders (NWRE) manufactures custom rubber extrusions using EPDM and other elastomers for a variety of industrial and OEM applications.
This guide explains what EPDM is, why it is commonly used for rubber extrusions, where it performs well, and when another material may be a better choice.
What Is EPDM Rubber?
EPDM stands for ethylene propylene diene monomer.
It is a synthetic rubber known for its ability to resist environmental conditions that can cause other elastomers to deteriorate.
Some of EPDM’s most important characteristics include resistance to:
- Ozone
- UV exposure
- Sunlight
- Water
- Weather
- Environmental aging
- Many temperature conditions
These properties make EPDM particularly useful for components installed outdoors or exposed to changing environmental conditions.
EPDM can also be formulated in different hardness levels and manufactured into a wide variety of custom extruded profiles.
What Are EPDM Rubber Extrusions?
An EPDM rubber extrusion is manufactured by forcing an uncured EPDM compound through a die designed to create a specific cross-sectional profile.
The extrusion is then processed and cured to develop its final physical properties.
Because the tooling determines the cross-sectional shape, EPDM can be extruded into many different configurations, including:
- D-shaped seals
- P-shaped seals
- Rubber tubing
- U-channels
- Solid strips
- Hollow profiles
- Bulb seals
- Weatherstripping
- Edge protection
- Custom geometric profiles
The ability to customize both the material and profile makes EPDM suitable for a wide range of sealing and protective applications.
Why Is EPDM Used for Outdoor Applications?
Outdoor environments can be demanding for rubber components.
A seal installed on exterior equipment may experience sunlight, rain, humidity, ozone, heat, cold, and repeated temperature changes.
Over time, environmental exposure can cause certain elastomers to harden, crack, lose flexibility, or otherwise deteriorate.
EPDM’s resistance to weathering is one of the main reasons it is commonly selected for exterior rubber products.
UV Resistance
Continuous exposure to sunlight can damage some rubber compounds.
EPDM provides excellent resistance to UV exposure, making it well suited for components that spend significant time outdoors.
Ozone Resistance
Ozone can contribute to cracking and deterioration in some elastomers.
EPDM offers excellent ozone resistance and is therefore frequently considered for long-term exterior applications.
Water Resistance
EPDM also performs well around water and moisture.
This makes it useful for seals and gaskets exposed to rain, humidity, and other wet conditions.
Combined, these characteristics make EPDM a strong candidate for many outdoor sealing applications.
Common EPDM Rubber Extrusion Applications
EPDM extrusions are used across numerous industries.
Common applications include:
Weatherstripping
EPDM’s environmental resistance makes it a natural choice for weather seals around doors, windows, equipment, and enclosures.
Construction Seals
Buildings and infrastructure can require rubber components capable of tolerating years of outdoor exposure.
EPDM may be used for sealing, isolation, cushioning, and protection in construction applications.
Automotive and Transportation
Vehicles encounter sunlight, water, temperature changes, vibration, and road conditions.
EPDM is commonly used in transportation-related sealing applications because of its resistance to weather and ozone.
HVAC Equipment
Heating, ventilation, and air-conditioning equipment may be installed outdoors and exposed to significant temperature and weather changes.
EPDM seals can be useful for equipment housings, access panels, and related applications.
Industrial Equipment
Outdoor industrial machinery may require seals, bumpers, channels, and protective profiles that can tolerate environmental exposure.
Electrical Enclosures
Enclosures often need compressible seals around doors and access panels to help protect internal components from environmental exposure.
Depending on the design requirements, EPDM can provide an effective solution.
NWRE manufactures custom extrusions for customers across a broad range of industries and applications.
EPDM Rubber for Seals and Gaskets
Sealing is one of the most common applications for EPDM extrusion.
The effectiveness of a seal depends on more than material selection alone.
Engineers also need to consider:
- Profile geometry
- Durometer
- Compression
- Wall thickness
- Surface contact
- Installation method
- Operating temperature
- Expected movement
For example, a hollow EPDM bulb seal can compress relatively easily when positioned between two surfaces.
A solid EPDM strip may require significantly greater force to achieve the same amount of compression.
Selecting the appropriate profile is therefore just as important as choosing EPDM itself.
Solid EPDM vs. Sponge EPDM
EPDM can be used in both solid and sponge rubber configurations.
Solid EPDM
Solid EPDM is dense and generally provides greater resistance to deformation.
It may be used for:
- Solid seals
- Rubber strips
- Bumpers
- Channels
- Protective profiles
- Industrial components
Sponge EPDM
Sponge EPDM contains a cellular structure that allows the material to compress more easily.
This can make it particularly useful for:
- Weather seals
- Door seals
- Enclosures
- Access panels
- HVAC equipment
- Gap filling
- Cushioning
Closed-cell sponge EPDM can also provide useful resistance to water absorption, depending on the compound and application.
The correct construction depends on the amount of compression and sealing pressure required.
What Is EPDM Durometer?
Durometer is a measure of rubber hardness.
EPDM can be formulated at different hardness levels depending on the requirements of the component.
A softer EPDM compound generally provides greater flexibility and may compress more easily.
A harder EPDM compound can provide greater resistance to deformation.
The appropriate durometer depends on:
- Seal design
- Compression requirements
- Mechanical stress
- Installation
- Required flexibility
- Profile geometry
Selecting a softer material isn’t always the best way to create a compressible seal.
In some cases, engineers can use a hollow profile geometry to provide the desired compression while maintaining other required material characteristics.
EPDM vs. Neoprene
EPDM and Neoprene are both widely used synthetic elastomers, but they offer different advantages.
EPDM generally provides superior resistance to:
- Outdoor weather
- Ozone
- UV exposure
- Water
- Environmental aging
Neoprene provides more balanced performance where moderate resistance to oil is also desirable.
If the primary challenge is long-term outdoor exposure, EPDM often deserves strong consideration.
If an application involves a combination of weather exposure and occasional contact with certain oils, Neoprene may also be evaluated.
EPDM vs. Nitrile
EPDM and nitrile have very different strengths.
EPDM is commonly preferred for:
- Weather
- Water
- Ozone
- UV exposure
- Outdoor environments
Nitrile is commonly preferred for:
- Petroleum oils
- Fuels
- Hydrocarbon exposure
- Machinery applications
If a rubber component will regularly contact petroleum-based oils, nitrile may be a better option.
If the component is primarily exposed to outdoor weather and water, EPDM may be the stronger candidate.
Material compatibility should always be evaluated against the actual substances and operating conditions involved.
EPDM vs. Silicone
EPDM and silicone can both provide excellent resistance to environmental aging, but their performance characteristics differ.
Silicone is particularly useful when an application involves demanding high- or low-temperature requirements.
It is used across industries including aerospace, medical, food processing, electronics, and industrial manufacturing.
EPDM may offer a more economical solution for many conventional outdoor weather-sealing applications where extreme temperature performance isn’t required.
For applications with demanding temperature requirements, custom silicone extrusions may be worth considering.
When Should You NOT Use EPDM?
Although EPDM is extremely versatile, it has limitations.
One of the most important is its compatibility with petroleum-based oils and fuels.
EPDM is generally not the preferred material when a component will regularly encounter:
- Gasoline
- Petroleum oils
- Certain hydrocarbon fluids
In these environments, nitrile or another compatible elastomer may provide better performance.
Chemical exposure should always be reviewed carefully.
A rubber material that performs well around one chemical may perform poorly around another.
This is why the actual operating environment should be identified before a material is selected.
Temperature Considerations for EPDM
Temperature is another important factor.
Rubber properties can change as temperature rises or falls.
At low temperatures, some elastomers can become less flexible.
At elevated temperatures, long-term material properties can also change.
The exact operating range of an EPDM compound depends on its formulation and the application.
When specifying an extrusion, engineers should identify:
Maximum operating temperature
Minimum operating temperature
Continuous versus intermittent exposure
Environmental conditions occurring at those temperatures
Temperature should never be evaluated independently from the rest of the operating environment.
NWRE’s Material & Engineering resources can help provide additional information when evaluating materials for a custom extrusion.
EPDM Profile Design Considerations
Once EPDM has been selected, attention turns to the profile itself.
Several factors should be evaluated.
Wall Thickness
Very thin or inconsistent wall sections can create manufacturing and performance challenges.
Hollow Sections
Hollow cavities can improve compressibility for sealing applications.
Corners
Sharp transitions may behave differently from gradual radii during extrusion and use.
Compression
The profile should be designed around the actual amount of compression available in the assembly.
Tolerances
Rubber is flexible, so tolerances should reflect the functional requirements of the component and the realities of elastomer manufacturing.
Installation
Consider whether the extrusion will:
- Slide into a channel
- Fit over an edge
- Be bonded to a surface
- Be mechanically retained
- Be compressed between components
Designing with the installation process in mind can make the finished component easier to use.
Can EPDM Extrusions Be Custom Made?
Yes.
Custom extrusion tooling allows EPDM profiles to be manufactured according to customer drawings and dimensional requirements.
Custom profiles may include:
- Seals
- Gaskets
- Tubing
- Channels
- D-profiles
- P-profiles
- Hollow seals
- Solid profiles
- Complex custom geometries
A custom profile can be especially valuable when standard rubber products don’t provide the required fit, compression, or sealing characteristics.
Depending on the project, secondary operations may also be incorporated after extrusion.
What Information Is Needed for an EPDM Extrusion Quote?
If you’re preparing to request pricing for a custom EPDM extrusion, providing detailed information can make the process more efficient.
Useful information includes:
Profile Drawing
Provide the cross-sectional dimensions whenever possible.
Material
Specify EPDM and any known compound requirements.
Durometer
Include the required hardness if it has already been established.
Tolerances
Identify critical dimensions.
Quantity
Provide anticipated order quantities or annual usage.
Length
Specify continuous, coiled, or cut lengths.
Operating Environment
Include exposure to:
- Weather
- UV
- Water
- Temperature
- Chemicals
- Oils
- Abrasion
Secondary Operations
Identify cutting, adhesive, joining, or fabrication requirements.
If you’re uncertain about the exact material or configuration, providing information about the application can help guide the discussion.
Is EPDM Right for Your Custom Extrusion?
EPDM is an excellent material for many applications, but the decision should always be based on performance requirements.
EPDM is particularly worth considering when a component requires:
- Excellent weather resistance
- Excellent ozone resistance
- UV resistance
- Water resistance
- Outdoor durability
- Good flexibility
- Long-term environmental stability
Another elastomer may be more appropriate when petroleum oils, fuels, extreme temperatures, or specialized chemicals are major considerations.
The most effective approach is to evaluate the entire operating environment before finalizing the material.
Custom EPDM Rubber Extrusions from Northwest Rubber Extruders
Northwest Rubber Extruders manufactures custom rubber profiles for customers across a wide variety of industrial markets.
Our custom extrusion capabilities allow customers to specify profile geometry, dimensions, material requirements, durometer, and other characteristics based on their application.
Learn more about our Rubber Extrusions, Silicone Extrusions, Material & Engineering, and Industries Served capabilities.
Need a custom EPDM profile manufactured to your specifications? Request a Quote from Northwest Rubber Extruders.