EPDM Gasket Material Properties 60 Durometer Rubber EPDM vs Neoprene

author: Qishine Industry

2023-05-16

One-Minute Overview

A 60 durometer gasket is Shore A 60, a medium-soft rubber that seals imperfect flange faces without squeezing out under bolt load.
EPDM handles -20°F to +250°F (-29°C to +121°C) and leads outdoors against ozone, UV, water, and steam.
Neoprene (CR) reaches -40°F to +250°F, tolerates moderate oil and abrasion better, and is preferred where flame resistance matters.
Buna-N seals petroleum oils best but starts at +20°F; Viton and PTFE reach +450°F with the widest chemical range.

What 60 Durometer Actually Tells You

Durometer is measured on the Shore A scale for rubber. A reading of 60A sits in the middle of the practical gasket range: soft enough to conform to a slightly wavy or pitted flange face, firm enough not to extrude into the gap when the bolts are torqued.

The number is a hardness figure, not a strength figure. Two gaskets can both read 60A and behave completely differently, because temperature resistance, fluid compatibility, and compression set come from the polymer, not the durometer. The most common mix-up is comparing hardness numbers when buyers should compare polymers first, then confirm the hardness suits the flange and bolt load.

EPDM vs Neoprene: Side-by-Side Properties

Property	EPDM	Neoprene (CR)	Buna-N (NBR)
Service temperature	-20°F to +250°F (-29°C to +121°C)	-40°F to +250°F (-40°C to +121°C)	+20°F to +250°F (-7°C to +121°C)
Weather, UV, ozone	Excellent - the benchmark elastomer	Good	Poor - degrades outdoors
Water and steam	Excellent	Good	Fair
Petroleum oil and fuel	Poor - swells badly	Moderate	Excellent
Acids and bases	Good across a wide pH range	Fair to good	Fair
Abrasion	Moderate	Good	Good
Flame resistance	Poor	Good - self-extinguishing grades exist	Poor
Typical gasket use	Outdoor, HVAC, water, cooling towers	Oil mist, weathering, abrasion	Oil, fuel, hydraulic service

The table is a starting point, not a verdict. Concentration, pressure, and continuous versus intermittent exposure all shift the answer, and a material that survives a splash test can fail in a static soak.

Reading Temperature Limits Correctly

Every published temperature range describes the continuous service window, not a short-term peak. Running an EPDM gasket at its upper limit for months differs from a brief excursion during a cleaning cycle.

The lower limits differ sharply by polymer: Neoprene reaches -40°F (-40°C), EPDM stops at -20°F (-29°C), and Buna-N only starts at +20°F (-7°C). In cold-climate outdoor service this single line decides the material.

Sections thicker than the standard 1/8 inch and 1/16 inch insulate the flange faces from each other, which slows heat transfer but changes compression behavior under torque. Always confirm gasket thickness against the bolt load available.

Where EPDM Wins

EPDM is the default elastomer for anything exposed to sunlight. It resists ozone cracking, UV degradation, and long-term weathering better than any other general-purpose rubber, which is why it dominates outdoor sealing, roofing, HVAC, and automotive exterior work.

It also performs well in hot water and steam and holds up across a wide pH range, making it a frequent choice for water treatment, cooling towers, and general chemical lines where oils are absent.

The limitation is decisive: EPDM swells severely in petroleum oils and fuels. If the line carries oil, EPDM is the wrong answer regardless of the temperature rating.

Where Neoprene Wins

Neoprene, or polychloroprene (CR), occupies the middle ground. It tolerates moderate oil exposure, resists abrasion better than EPDM, and reaches -40°F (-40°C) at the cold end, a 20°F advantage in winter-exposed installations.

Its other distinguishing property is flame resistance. Self-extinguishing grades are available, which is why Neoprene appears in marine, rail, and underground work where a burning gasket would be unacceptable.

Where it falls short is heavy aromatic or fuel exposure. Neoprene swells in these media, and Buna-N takes over.

Where Buna-N Fits and Where It Does Not

Buna-N, or nitrile rubber (NBR), is the best general-purpose oil-resistant elastomer in this group. It handles petroleum oils, hydraulic fluids, grease, and fuels that would destroy EPDM.

Two caveats matter. Its low-temperature floor is +20°F (-7°C), so it is unsuitable for freezing outdoor service, and it degrades quickly under sunlight and ozone, so it belongs inside equipment, not on exposed flanges.

Above all three sit Viton (FKM) at up to +450°F (+232°C) with broad chemical resistance, and PTFE at up to +450°F with the widest chemical compatibility listed here.

Common Selection Mistakes

Choosing by temperature alone. A gasket that survives the heat but swells in the medium fails within weeks.
Assuming a harder gasket seals better. A 70A or 80A sheet resists extrusion but conforms less; on a pitted or warped face it can leak where a 60A gasket would seal.
Ignoring the flange and bolt load. Gasket hardness must match the available compressive stress: too soft and it extrudes, too hard and the bolts never develop enough seating stress.
Reusing a compressed gasket. Rubber takes a permanent set once torqued, so a gasket that has been in service should not go back in.

Specifying the Right Gasket

A workable sequence is to identify the medium first, then the temperature range including start-up and cleaning cycles, then the flange type and pressure class, and only then the hardness and thickness.

State the standard where one applies, such as ASME B16.21 for non-metallic flat gaskets and ASME B16.20 for spiral wound and ring joint gaskets, because dimensional compliance is usually what a buyer is checking.

For insulating gasket kits the sealing ring is only one element. The sleeve, insulating washer, and steel washer form the dielectric barrier together, so the sealing material must be selected alongside the G10 or G11 sleeve grade rather than in isolation.

FAQ

Is 60 durometer harder or softer than 70 durometer?

Softer. On the Shore A scale a higher number means a harder rubber. 60A conforms more readily to imperfect flange faces, while 70A resists extrusion better under higher bolt load.

Can EPDM be used for oil service?

No. EPDM swells severely in petroleum oils and fuels and loses sealing force. For oil service choose Buna-N (NBR) or Viton (FKM).

Which is better for outdoor use, EPDM or Neoprene?

EPDM. It resists ozone, UV, and long-term weathering better than Neoprene and is the standard for exposed outdoor sealing. Neoprene is better where moderate oil contact or flame resistance is also required.