Sealing Specialties stocks over 6000 sq. feet of o-ring inventory. We are proud to represent the most respected names in the business which include Parker, Precix, Parco, and Precision. We stock all compounds and sizes for same day shipment. Compounds include nitrile (buna n), ethylene propylene (EPDM), fluoroelastomer (FKM, Viton®), Neoprene®, silicone, perfluoroelastomer (FFKM), polyurethane, and aflas to name the most common. All other compounds are also available. Metric sizes, micro-minature, custom sizes, spliced and vulcanized, and (AS 568) standard sizes are all available from stock or with short lead times. Whether your requirement is for annual high volumes or immediate low quantities we are able to assist you.
O-Ring Size Chart
Nitrile (NBR or Buna N)
Due to it’s ability to be compounded for service over a temperature range of -65°F to +275°F, and it’s excellent resistance to petroleum products, Nitrile is the most widely used elastomer. Nitrile o-ring compounds can exhibit excellent compression set resistance, tear resistance, and abrasion resistance.
These compounds do not exhibit good resistance to ozone, sunlight or weather.
Fluorocarbon (Viton® or FKM)
Since it’s introduction in the mid 1950’s, Fluorocarbon elastomers (most commonly known as it’s Trademarked Viton name) are the most significant development in recent history. Due to it’s excellent mechanical and physical properties, and outstanding resistance to a wide spectrum of chemicals, Fluorocarbon compounds have grown to be a major importance in the seal industry. Fluorocarbon o-ring compounds exhibit excellent high temperature resistance and low compression set. The normal operating range of Fluorocarbon is -20°F to +400/450°F with certain compounds formulated to operate outside this range.
The Silicone compounds exhibit excellent resistance to temperature extremes from
-150°F to +500°F. Certain compounds have been developed to operate outside this range. Silicone is not recommended for dynamic service due to its poor abrasion resistance, tensile strength and tear resistance. Silicone is utilized in applications, which expose seals to high temperature dry heat, ozone and weathering.
Ethylene Propylene (EPM, EPDM, EP, EPR)
This compound found broad acceptance in applications requiring excellent resistance to Skydrol and other phosphate ester fluids at higher temperatures. In addition, o-rings in these compounds exhibit excellent resistance to automotive brake fluids and steam. Ethylene Propylene compounds are also recommended in applications requiring resistance in hot water/steam, weather, ozone, abrasion, tear and tensile strength. EPDM has a temperature range of -65°F to +300°F.
Neoprene (CR, Chloroprene)
Neoprene was the earliest of the volume American synthetic elastomers. Neoprene compounds exhibit fair oil resistance, good ozone and weather resistance. Neoprenes are used in refrigeration systems due to their resistance to refrigerants such as Freon. Due to its relatively low cost and broad temperature range, Neoprene is popular in many general service applications. The temperature range for Neoprene is -65°F to +250/300°F.
These compounds exhibit the good low/high temperature properties of silicone but with basic fuel and oil resistance. They are used in aerospace applications for fuel systems and applications requiring resistance to diester base lubricants to 350°F. Like Silicone, Fluorosilicone has limited strength and abrasion resistance, and thus is generally recommended for static applications. The sealing temperature service range is -80°F to +350/400°F.
Polyurethane (AU, EU)
Polyurethane compounds exhibit high tensile strength, excellent abrasion and tear strength making it the toughest of the elastomers. Compression set and heat resistance are inferior to other elastomers such as Nitrile. These materials may be suitable for hydraulic applications, which exhibit abrasive contaminants or shock loads. The service temperature range for these compounds is -65°F to +212°F.
Compounded to resist the most demanding environments, Perfluoroelastomer compounds solve the most critical application problems. Perfluoroelastomers can resist higher temperatures, the broadest range of aggressive chemicals, and provide performance beyond all other available elastomer families. Parker "Parofluor" can handle temperatures up to 608° F (depending upon compound), and exhibit excellent properties in critical environments of semi-conductor fabrication, aerospace, chemical processing, energy exploration, pharmaceutical, and other aggressive sealing applications. Kalrez™ and Chemraz™ are also members of the perfluoroelastomer family.
The O-Ring Division designs and manufactures engineered elastomeric O-Ring seals - including high-performance materials for nearly every sealing application.