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QUOTE

EPDM gaskets

EPDM gaskets for weather, water and steam.

EPDM shrugs off sunlight, ozone, rain, hot water and steam for years, which makes it the rubber of choice for outdoor and water seals. Ask us about EPDM gaskets and washers cut to your drawing, and we will help you choose a grade that suits the service.

Request a quoteEPDM properties
Typical service range of EPDM
-50°C to +150°C
EPDM swells in mineral oils and fuels
Not for oil

Why EPDM

Why EPDM is the outdoor gasket rubber.

EPDM, ethylene propylene diene monomer rubber, has a saturated backbone: the chain that carries its strength has none of the double bonds that ozone and ultraviolet light attack in natural rubber and nitrile. That is why EPDM door seals, roof membranes and pipe gaskets last for decades in the open air.

The same chemistry makes it at home in water. EPDM resists hot water, steam, glycol coolants, many dilute acids and alkalis, and the phosphate ester fluids that attack other rubbers. It stays flexible to about -50°C and, in peroxide-cured grades, works to about 150°C.

Its one big weakness is oil. Mineral oils, fuels and greases swell EPDM badly, so it is never the rubber for an engine or gearbox. Our guide to rubber gasket materials shows where it sits among the other elastomers.

All rubber gasket materials

Properties

EPDM properties for gasket design.

These are typical values for solid EPDM sheet, for comparing materials at the design stage. The data sheet for the grade supplied applies to your part.

The way EPDM is cured matters. Sulphur-cured grades are economical and suit general weather and water seals to about 120°C. Peroxide-cured grades resist heat, steam and compression set better, and are the usual choice for hot water and drinking water service. For continuous dry heat above 150°C, silicone gaskets go further.

EPDM and other materials compared

Solid EPDM: typical properties

General values, not a specification

General

Polymer
Ethylene propylene diene monomer rubber (EPDM)
Density
1.1 to 1.4 g/cm³, by compound

Mechanical

Hardness
40 to 90 Shore A; 60 to 70 Shore A is common
Tensile strength
5 to 15 MPa, by grade
Elongation at break
200% to 500%
Compression set
Good; best in peroxide-cured grades

Thermal

Service temperature
-50°C to +150°C (peroxide-cured)
Sulphur-cured grades
To about +120°C

Resistance

Ozone, UV and weather
Excellent
Hot water and steam
Very good in peroxide-cured grades
Glycol coolants and brake fluids
Good
Dilute acids and alkalis
Good
Attacked by
Mineral oils, fuels, greases and hydrocarbon solvents

Typical published values for solid EPDM. Ask for the data sheet of the grade supplied.

Ordering

Ordering EPDM gaskets cut to your drawing.

Tell us the part and the service, and we will confirm the EPDM grade, thickness and cutting method with the quotation. The most useful details are the size, tolerance and quantity, the fluid or exposure, the highest and lowest temperatures, and any approval the part needs, such as drinking water or food contact.

For production runs, die cutting gives fast, consistent parts at a low unit cost; thick sheet and prototypes are usually water jet cut.

  • Cut to your drawing

    Gaskets, washers, pads, strips and complex profiles.

  • Grade advice

    Sulphur or peroxide cure, solid or sponge, matched to the service.

Contact our sales team

EPDM gaskets

What to ask us for

Solid EPDM sheet
Thicknesses on request
Closed-cell EPDM sponge
On request
Peroxide-cured grades for steam
On request
Drinking water (WRAS-approved) grades
Ask us
Parts
Gaskets, washers, pads and flat seals
Cutting
Die cut or water jet cut, by thickness

Grades, thicknesses and approvals are confirmed with the quotation.

Applications

Where EPDM gaskets are used.

EPDM is specified wherever a seal lives outdoors or in water, and oil is not part of the picture.

All sectors
A set of cut gaskets for a car transmission

Limits

Why EPDM and oil do not mix.

Like dissolves like. EPDM is a non-polar hydrocarbon rubber, and so are mineral oils, fuels and greases. When they meet, the oil soaks into the rubber, which swells, softens and loses its strength; a gasket that has swollen can extrude from the joint or tear on removal. Even an oily film from assembly lubricant or a contaminated flange can damage it over time.

So EPDM is never used in engines, gearboxes, hydraulic systems or fuel lines. Where oil and weather both matter, nitrile or neoprene, the all-round gasket rubber is the usual compromise, and FKM covers the hottest and most aggressive cases.

The flip side is useful: fluids that attack oil-resistant rubbers, such as glycol brake fluids, phosphate ester hydraulic fluids, hot water and steam, are exactly where EPDM excels.

If the gasket will see oil, EPDM is the wrong rubber.
Talk to our technical team

Alternatives

EPDM, neoprene or silicone for outdoor and water seals?

All three weather well, but they part company over steam, oil, heat and flame. Choose what the gasket has to cope with to see which qualifies.

What does the gasket meet?

Choose properties to find the right material. 3 materials compared.

EPDM, neoprene or silicone for outdoor and water seals?
RequirementEPDMNeopreneSilicone
Outdoor weather, UV and ozoneEPDM and silicone last longest.YesYesYes
Hot water and steamSilicone degrades in steam above about 120°C.YesNoNo
Light oil or grease contactNoYesNo
Continuous heat above 150°CNoNoYes
Cold below -40°CYesNoYes
Flame resistanceNoYesNo
Tear and abrasion resistanceYesYesNo
Food-contact grades existYesNoYes

General guidance for each rubber family; compounds vary. The data sheet for the grade supplied applies.

EPDM gasket FAQs

EPDM gasket questions, answered.

Can't find what you need? Our technical team is happy to help.

Ask our team
Is EPDM oil resistant?

No. Mineral oils, fuels and greases swell EPDM, which softens and loses strength. Do not use it in engines, gearboxes, hydraulic systems or fuel lines. Nitrile is the standard oil-resistant rubber, and FKM fluoroelastomer covers hotter and more aggressive oils and fuels.

Is EPDM UV and ozone resistant?

Yes, outstandingly so. EPDM's saturated polymer backbone gives ozone and ultraviolet light nothing to attack, so EPDM seals typically last many years outdoors without cracking. That is why it is used for weatherstrips, roof membranes, outdoor enclosures and window seals.

EPDM or neoprene?

Choose EPDM for long life outdoors, for hot water and steam, and for cold down to about -50°C. Choose neoprene where the seal may meet some oil or grease, or where flame resistance matters, because EPDM swells in oil and burns more readily.

Can EPDM be used with drinking water?

Yes, in the right grade. In the UK, rubber in contact with drinking water should be approved by WRAS, tested to BS 6920, and peroxide-cured EPDM is widely used for it. Ask us about an approved grade for your part, and we will confirm what is available with the quotation.

What temperature can EPDM gaskets take?

EPDM is typically used from about -50°C to +150°C in peroxide-cured grades, and to about +120°C in sulphur-cured grades. It also handles hot water and low-pressure steam well in the right grade. The data sheet for the grade supplied gives its rated limits.

Need EPDM gaskets for your part?

Send us the drawing, the fluid or exposure, the temperatures and the quantity, and our technical team will confirm a suitable grade and quote for the cut parts.

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