Complete Guide to O-Rings and Seals

O-rings are critical engineered components that play an important role in many diverse industries and applications. Constructed from an array of durable materials, O-rings provide a tight, leak-proof seal that prevents liquids or gases from escaping. At RD Rubber Technology, we provide quality engineered solutions. In this guide, you can learn more about how O-rings are designed to function, their uses, and the unique material characteristics.

How O-Rings Work
Applications
How O-Rings Are Made
Materials
Custom Rubber Seals and O-Rings

How O-Rings Work
Applications
How O-Rings Are Made
Materials
Custom Rubber Seals and O-Rings

Named after their circular shape, O-rings are made from resilient, leak-proof materials. Their function is to form a tight seal and retain their original shape after compression. O-rings are installed inside grooves between two surfaces where they fill any spaces between the two joining components. This prevents liquids or gases from escaping. As higher amounts of pressure are placed on the joining surfaces, the O-rings becomes increasingly distorted, which improves the seal quality.

These versatile engineered components are used throughout a range of demanding environments. Since they are exposed to many different substances and temperature ranges depending on usage, there is no one-size-fits-all material. Instead, O-rings can be constructed from a selection of high-performance materials, depending on the specific needs of each application.

Applications of O-Rings Seals

Many industries work with assemblies that require leak-proof or tight sealing for function. Pumps, valves, and connectors all feature separate parts that must be joined together to prevent fluid or gas from leaking. O-rings, with their exceptional versatility, meet these needs. O-rings are compatible with static, dynamic, pneumatic, and hydraulic components.

O-rings, manufactured from high-performance materials, provide a long and reliable service life. When exposed to pressure, O-rings move toward the lower-pressure side of the assembly, increasing the tightness of the seal. It’s important to note, however, that excessive stress can result in deformation and potential seal failure. While O-rings return to their original shape after use, repeated use does degrade the material over time. For this reason, regular inspections are required to ensure reliability.

Below, we’ll explore some of O-rings critical uses.

Aerospace

The aerospace industry requires O-rings with a high level of chemical resistance. It’s also crucial that they be able to withstand large temperature fluctuations and pressure ranges. Some of the most common materials include nitriles, ethylene-propylene (EPDM and fluoroelastomers. Specific O-rings applications within the aerospace industry include fuel systems, fuel cap gaskets, and valve cover seals.

High-Temperature Sealing

Engine seals, aerospace components, and food processing equipment are all applications that involve extreme temperatures. O-rings used in these environments must be able to maintain seal integrity under thermal expansion and contraction. High performance materials include:

Viton^®: Suitable for high temperatures
EPDM: Resists hot water and steam
Silicone: Suitable for broad temperature ranges.

High-Pressure Sealing

Applications such as hydraulic systems, high-performance engines, and industrial machinery require O-rings that resist mechanical stress and deformation under high pressures. It’s also important that O-rings exhibit good durability under dynamic conditions. Common O-rings materials for high-pressure sealing applications include EPDM, nitrile, and Viton^®.

Engines

High-performance engines require durable O-rings that are resistant to pressure, heat, leaks, and chemicals.

CO2

Applications that involve prolonged exposure to CO2 require unique solutions to ensure consistent seal integrity. Polyurethane, nitrile and fluoroelastomers are commonly used options since they resist CO2 absorption and will not swell. They also provide reliable durability against CO2-induced degradation.

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How O-Rings Are Made

O-rings can be molded using several possible methods, such as:

Compression Molding
Transfer Molding
Injection Molding
Liquid Silicone Rubber Molding

Custom molded O-rings are made from select materials. The O-rings material selection and engineering process requires an in-depth consideration of the end-use application and its needs. It’s important to consider environmental factors, as well as the required quality and quantity of products.

What Materials Are Used to Create O-Rings?

At RD Rubber Technology Corporation, we work with high-performance materials to ensure quality engineered solutions for the most demanding applications. Below, you’ll find an overview of high performance materials we use to manufacture O-rings and their unique characteristics.

Viton^® is a fluoroelastomer and registered trademark of the Chemours Company. It offers excellent resistance to chemicals, heat, steam, and mechanical stress. O-rings made from this material are suitable for hard vacuum service and applications that involve exposure to petroleum oils, silicone fluids, and high temperatures. Viton^® withstands temperatures ranging from -20 °F to 450 °F (-29 °C to 232 °C) as well as intermittent temperatures up to 500 °F (260 °C).

Nitrile, also known as Buna-N, is a widely used material for food-related applications, as well as fuel systems. It is suitable for exposure to vegetable oil, steam, water, and cleaning agents. While O-rings made from Nitrile cannot be exposed to certain sanitizing agents, they do offer mild alkali resistance. Nitrile withstands temperatures ranging from 40 °F to 225 °F (-40 °C to 107 °C).

Silicone is a popular material for the food and beverage industry since it does not affect the flavor of the substances it comes into contact with. It’s also a popular material for medical and outdoor-related applications. Silicone is resistant to UV rays, ozone, and fungal growth. It can withstand temperatures ranging from -50 °C to 200 °C.

Neoprene is a weather, water, and chemical-resistant material that’s widely used in refrigeration systems. It is resistant to UV light, ozone, oxidation, petroleum, and many chemicals. Neoprene also has an elastic and cushioning effect. It is suitable for exposure to temperatures ranging from -20 °F to 180 °F (-29 °C to 82 °C).

Ethylene propylene diene terpolymer (EPDM) is a highly durable material that displays excellent resistance to UV light, ozone, abrasive chemicals, and tough weather conditions. While it offers good tensile strength, it is not suitable for applications involving oil-based products. EPDM O-rings are commonly used in outdoor environments, water systems, and steam-related applications. They can withstand temperatures ranging from -55 °F to 275 °F (-48 °C to 135 °C).

The copolymer butyl has an ASTM designation of IIR (isobutylene isoprene rubber). This synthetic rubber strikes an ideal balance between flexibility and durability, making it an effective choice for water- and airtight sealing applications. It ranges in hardness between 30 and 90, Shore A, and has a shelf life of 15 years and provides excellent chemical resistance.

Custom Rubber Seals and O-Rings

At RD Rubber, our custom seal and gasket engineering services are backed by over 35 years of industry expertise. We offer many material options including:

EPDM

Butyl, Chlorobutyl, Nitrile

Fluorosilicone

Silicone

LIM and HCR

Fluorocarbon Rubber

Viton, FKM

We can mold any thermoset elastomer and provide custom material formulation to meet the most challenging application-specific needs. Our experienced engineering team can customize compression set, permeation, environmental resistance, and color matching. We are ISO 9001 and AS9100 certified, ITAR and DOD registered and compliant to NIST 800-171 requirements. We manufacture precision molded rubber products for critical to function applications for OEM’s serving Aerospace, Defense, Military, Healthcare, Industrial, Food and Dairy Processing industries from customer supplied designs and specifications.

If you require a custom O-rings or seal solution, reach out to our team with any questions or request a quote to get started today.

Contact Our Team Today

Get in touch with our team of experts and engineers by contacting us or requesting a quote

Complete Guide to O-Rings and Seals

Complete Guide to O-Rings and Seals

How O-Rings Work

Applications of O-Rings Seals

Aerospace

High-Temperature Sealing

High-Pressure Sealing

Engines

CO2

How O-Rings Are Made

What Materials Are Used to Create O-Rings?

Viton® remove

Nitrile (Buna-N) add

Silicone add

Neoprene add

EPDM add

Butyl add

Custom Rubber Seals and O-Rings

Contact Our Team Today