O-Rings - EPDM, 70 Shore A

O-rings are circular sealing rings with a round cross-section. When an O-ring is fitted into a groove and compressed between two surfaces, it forms a seal that prevents the escape of liquids or gases. O-rings are suitable for both static and dynamic applications.

These O-rings are made from EPDM (ethylene propylene diene monomer rubber). EPDM has excellent resistance to water, steam, ozone, sunlight and weathering, which makes it well suited to water systems and outdoor use. At 70 Shore A, the material offers a good balance of flexibility and durability, making it the standard choice for general-purpose sealing.

Chemical Compatibility

EPDM is recommended for use with hot water and steam, glycol-based brake fluids, glycol-based coolants, alcohols, silicone oils, and dilute acids and alkalis. The maximum temperature for hot water and steam depends on the grade of EPDM.

Limitations

EPDM is not recommended for use with mineral oils and greases, petroleum-based hydraulic oils, petrol, diesel or other hydrocarbon fuels, aliphatic or aromatic hydrocarbons, or chlorinated solvents.

Applications

These O-rings are suitable for hot water and steam systems, automotive brake and cooling systems, valves, and equipment used outdoors.

Installation Guidance

Make sure that the groove and mating surfaces are clean and free from burrs. The 70 Shore A compound is flexible enough to fit easily and to seal well against a range of surface finishes. For high-pressure applications or larger clearance gaps, a harder grade or back-up rings may be required to prevent extrusion. Use only a silicone-based lubricant when fitting; never use mineral oil-based greases or oils, as these will damage EPDM. Do not stretch or roll the O-ring over sharp edges or threads.

All dimensions are nominal. The information provided by AH Design Components Ltd is for reference only and is not a manufacturing specification. Please confirm that the product is suitable for your application before use.