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EPDM vs. Buna-N

Arizona Sealing Devices is a leading manufacturer and distributor of O-rings, gaskets, plugs, clamps, cable ties, and other commercial and industrial sealing components. We provide standard and custom molded parts as well as military-certified components. Our company is ISO 9001:2015 and AS9120B certified, dedicated to serving customers with small or large orders of high-quality molded components. We work with a wide variety of thermoplastics, rubbers, and other materials to address the needs of unique commercial, industrial, military, medical, and food applications.

Ethylene propylene diene monomer (EPDM) and nitrile butadiene (Buna-N) are two types of rubber that we use to produce sealing components. Although they look alike, EPDM and Buna-N have specific applications for which they are best suited. We will discuss the differences between EPDM and Buna-N, including their respective properties and applications.

Differences Between EPDM and Buna-N

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While both EPDM and Buna-N rubbers are durable, reliable, and resistant to certain types of conditions, each material has its own strengths that make it a good fit for particular applications. Some of the key differences between the two include:

  • Usable temperature range: Buna-N offers a temperature range of -40 °C to 107 °C for most applications, including dairy and food processing operations. EPDM, on the other hand, has a temperature range between -48 °C and 135 °C, making it more applicable across a greater range of cold and heat settings, such as hot water and steam environments.
  • Chemical resistance: EPDM is resistant to deionized water and acidic, alkaline, and alcohol substances used in common cleaning agents. However, EPDM can be easily damaged by exposure to petroleum-based chemicals. Buna-N offers high resistance to damage from petroleum-based fluids, but it can be damaged by exposure to acids and alkaline chemicals over time.
  • Resistance to environmental damage: EPDM is well-regarded for its excellent resistance to weather, including ozone and UV light exposure. This makes it more resistant to aging, especially in outdoor and water-based applications. Buna-N is less resistant to ozone and generally should not be used in outdoor areas.
  • Physical properties: Buna-N offers good physical properties, but EPDM is resistant to abrasion and offers high tensile strength.


Because of these differences, EPDM is commonly preferred for use cases that require added durability, especially with outdoor elements and extreme temperatures. Buna-N’s properties make it an excellent choice for systems that come into contact with petroleum-based chemicals. Here are more details on the best applications for both materials.


EPDM is strong, durable, and can withstand frequent cleanings. Because it can also withstand weathering and water exposure, it’s an excellent option for seals and components in systems that handle, process, or store water. Some of the most common applications for EPDM components include:

  • Automotive components
  • Auto brake systems
  • Bumpers
  • Conveyor belts
  • Dust covers
  • Electrical components
  • Gaskets
  • HVAC parts
  • Water storage components
  • Weatherstripping


Because Buna-N is a synthetic rubber copolymer, it has a stable structure that resists damage from petroleum-based chemicals. This makes the material an excellent choice for storing or processing petrochemical products. Some of the most common applications of Buna-N are:

  • Fuel handling hoses
  • Grommets
  • Hydraulic fluid seals
  • Hydraulic hoses
  • Mounts for shock and vibration
  • O-rings
  • Oil handling equipment
  • Rollers
  • Transmission fluid seals

High-Performance EPDM and Buna-N Seals From Arizona Sealing Devices

Choosing the right rubber or thermoplastic material for your sealing products is essential for ensuring long-term performance. At Arizona Sealing Devices, we have an extensive inventory of different sealing components constructed from popular polymers that are built to last in commercial, industrial, and military applications. Contact us today to learn more about our manufacturing, distribution, and other capabilities.

Square Rings (Gasket)

Arizona Sealing Devices was founded in 1989 as an O-ring supplier. Today, our wide selection of high-quality products includes square rings, gaskets, seals, plugs, and more. Browse our extensive inventory in our online catalog. We’re committed to helping you find the best sealing solution for your application.

Square O-Rings, Gaskets, and Seals

As a leading distributor of standard and custom gaskets and other sealing solutions, we have a wide range of products to choose from.

  • O-Rings: The traditional round O-ring is versatile and reliable, sealing in any direction with little compressive force. Square O-rings have a square cross-section, which allows for a tighter seal on all surfaces, including uneven or irregular surfaces. The quad O-ring, also called an X-ring, features a four-lobed design to provide twice the sealing surface of a round O-ring.
  • Gaskets: Made of a variety of materials — including felt, silicone, neoprene, and more — gaskets create a mechanical seal between irregular surfaces. They’re trusted in mission-critical applications in the aviation, military, agricultural, and automotive industries. 
  • Seals: Among our many sealing solutions, we offer Viton, a synthetic rubber elastomer that is easily molded into precise shapes ideal for a variety of applications. Viton offers excellent heat, flame, acid, weather, ozone, and oil resistance. 

Applications of Square Ring Seals

Click to ExpandSilicone O-Rings

Square-cut O-rings are especially useful for thin sealing areas and when the sealing load force is high. They are used in many industries, and each application takes advantage of different O-ring materials and their unique properties to withstand extreme conditions. Some common industries in which square ring seals are used include:

  • Wastewater: O-rings in wastewater applications must be corrosion- and chemical-resistant to withstand the harsh chemicals and materials to which they are exposed.
  • Food and Beverage: Food and beverage O-rings must be nontoxic, hypoallergenic, bacteria-resistant, chemical-resistant, and temperature-resistant to meet FDA guidelines and keep products safe for consumption.
  • Electronics: Sealing components protect electronics from environmental conditions and electromagnetic and radio frequency interferences.
  • Oil and Gas: Oil and gas applications require chemical-, temperature-, and abrasion-resistant o-rings to ensure safe rig operations.
  • Aviation: O-rings are often used in electrical components and fuel systems due to their ability to withstand high speeds, drastic pressure changes, extreme temperature fluctuations, and fluid exposure.
  • Automotive: Often used in braking systems and engines to prevent leakages and protect components against external elements.
  • Medical: O-rings are imperative for any medical device that operates using valves, pumps, or cylinders. Medical O-rings must comply with FDA standards and be able to withstand extreme temperatures and frequent sanitizing.
  • Industrial: The versatility of o-rings allows them to be used in hydraulic, pneumatic, static, and dynamic industrial processes to keep them functioning efficiently.

Materials Used to Ensure a Protective Seal

Because different materials offer different types of protection, it is important to choose the right material to withstand the specific conditions of your application. The effectiveness of your seal depends upon the material you choose as well as the custom size, shape, and dimensions of your O-ring or gasket. 

  • Buna/nitrile: High tensile strength, corrosion- and abrasion-resistant, one of the most common material choices for O-rings
  • AFLAS®: Temperature and chemical resistant, common in oil, gas, aerospace, and industrial applications
  • Butyl: Low permeability, excellent for vacuum sealing
  • Ethylene propylene: Similar to butyl with better ozone and chemical resistance
  • Fluorocarbon (Viton®): Common in high-temperature, high-exposure applications like engines and fuel handling systems, one of the best overall material choices available
  • Fluorosilicone: Fuel resistant, temperature stable, common for aerospace fueling and static sealing
  • Hydrogenated nitrile: Oil-resistant, corrosion-resistant, stronger than standard nitrile
  • Silicone rubber: Temperature-resistant, medical-grade silicone is available, common for static sealing in extreme temperatures 
  • Neoprene: Chemical-resistant, temperature-resistant, high strength, common in refrigerator sealing
  • Cast polyurethane: Abrasion-resistant, common in high-wear applications
  • Millable polyurethane: Similar to cast polyurethane with lower tensile strength 
  • Kalrez®: Extremely chemical-resistant, common in oil and gas, chemical processing, and paint applications
  • Polytetrafluoroethylene (PTFE): Chemical-resistant, temperature-resistant, requires care in installation because it has poor elastic memory at room temperature

With our range of materials and custom solutions, Arizona Sealing Devices has become a trusted distributor of O-ring kits and solutions, including vulcanized and spliced O-rings. No matter your industry or application, we can help you find the ideal sealing solution. Contact us to learn more or request a quote today.

Silicone O-Rings

At Arizona Sealing Devices, we offer a wide selection of O-rings with different cross-sections, sizes, and styles to suit a range of applications. With so many options available, we are here to help you determine the best material for your application.

Silicone is a superior material for sealing devices like O-rings. It is ideal for static sealing applications in high-temperature environments and has exceptional flexibility and resistance to fatigue. Silicone is exceptionally durable and can resist environmental factors like UV rays, oxygen, and ozone exposure. The unique properties of silicone can also be adjusted or enhanced to deliver improved performance when necessary.

What Is a Silicone O-Ring?

Click to ExpandSilicone O-Rings

Made from elastomers, O-rings are molded into a ring shape and bear a circular cross-section. Depending on the application, O-rings can be customized with unique cross-sections such as L- or T-shapes. They can also come in a cord-like solution made of plastic or similar materials. The cord can be cut to length and connected at both ends for a custom fit.  These versatile components are used in many static and dynamic applications to seal liquids and gases. Silicone is an ideal material for O-rings, offering various characteristics to improve performance, including:

  • Fungal growth resistance
  • UV, oxygen, and ozone resistance
  • Withstands extreme temperatures
  • Weather resistance
  • Withstands oil and grease from plant or animal sources
  • Electrically insulating
  • Flexible
  • Resists compression

Silicone can withstand temperatures between -75° and 450° F and can be formulated to meet several requirements, including compliance with FDA, Canada AG, 3-A, USDA, and USP Class VI standards. Silicone O-rings can have a hardness between 30 and 80 shore A Durometers.

How Silicone O-Rings Work

Silicone O-rings are activated by pressure to form a seal. They can effectively seal under high pressures and begin to deform as pressure is applied, pressing the silicone ring against the gland walls or seal joints. The seal provides a mechanical barrier to block fluids from entering the seal when pressurized.

Silicone Components & Properties

The term silicone describes a family of polymers made from synthetic compounds consisting of repeating units of siloxane or polysiloxane. Silicone rubber’s properties make it a generally non-reactive and stable material, allowing it to resist a range of harsh conditions. Silicone does not become brittle at low temperatures and can withstand high temperatures. It can perform in demanding applications, and its properties make it ideal for medical devices, electronics, and food storage applications.

Silicone O-Rings From Arizona Sealing Devices

Silicone is an ideal material for sealing devices like O-rings. The material resists a wide range of environmental factors. It is flexible, insulating, and ideal for extreme temperatures, making it suitable for many different industries and applications. Silicone grades can also be safe for medical and food uses and are recognized by organizations like the FDA and USDA.

At Arizona Sealing Devices, we offer silicone O-rings in a range of sizes and styles. Our sealing experts can help you find the ideal sealing solution for your application and have experience working with medical, transportation, electronics, oil and gas, chemical processing, water systems, food production, and various other industries. Our goal is to fully satisfy your needs with on-time delivery, affordable products of the highest quality, and exceptional customer service. Contact us to learn more about our silicone O-rings today.

Vulcanized O-Rings

An O-ring is a type of mechanical gasket used primarily in static applications to provide reliable sealing. Vulcanizing an O-ring makes it impermeable by liquids and gases, further extending its potential list of applications. At Arizona Sealing Devices, we carefully consider user requirements and application details to identify the ideal sealing solution for every client. To browse our solutions, please view AZ Seal’s catalog.

Overview of Vulcanized O-Rings

Generally speaking, vulcanized O-rings provide an ideal selection for static sealing. This is especially true in applications unsuitable for molded O-rings, such as those with oversized or non-standard measurements. Vulcanized O-rings are also viable when only a few pieces are needed, or when a customer needs an O-ring as quickly as possible and cannot wait the standard lead time for molded production.

When selecting a vulcanized O-ring for your next job, there are a few qualities to consider. These include the type of rubber used, the color, the durometer, the cross-section, and the cord thickness. Common materials used to make vulcanized O-rings include:

  • Viton®
  • Buna-N
  • Silicone
  • Polyurethane
  • Neoprene

The cut length of a vulcanized O-ring is calculated based on the desired diameter. There are two different cut angles to choose from:

  • The butt cut is a default 90-degree cut, where the cord gets cut straight from top to bottom on the ring itself.
  • A bevel cut, also known as a skive cut, occurs at a 45-degree angle. This cut ensures that more of the material’s surface area remains in contact at the joint to provide a stronger seal.

Advantages and Applications of Vulcanized O-Rings

Overview of Vulcanized O-Rings

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All told, vulcanized O-rings offer a wide range of benefits. Some of these benefits may include:

  • Ability to accommodate profiles too large for molding
  • Custom sealing
  • High bond integrity
  • Strong and nearly undetectable joints
  • Short production lead times
  • No tooling required

Vulcanized O-rings are also quite versatile. These sealing solutions see frequent use in electronics, aerospace, healthcare, construction, transportation, food processing, power generation, and more.

FAQs on Vulcanized O-Rings

Are vulcanized O-rings right for my application?

Vulcanized O-rings can be used in any situation where a flange or lid must seal. The application itself doesn’t need to be round. If there are moving parts around the O-ring, then a vulcanized O-ring would not be an ideal solution.

How do you inspect a vulcanized joint?

First, locate the splice joint on the vulcanized O-ring. Using your fingers, give it a slight twist in either direction. Do so gently, or the O-ring may break. Also avoid bending the O-ring at the joint to avoid breakage. Provided that the vulcanized O-ring passes this “twist and tug” test, it is safe for installation or continued use.

Vulcanized O-Rings From Arizona Sealing Devices

Arizona Sealing Devices can provide the sealing solutions you need. Whether you’re looking for vulcanized O-rings, spliced O-rings, or another gasket or sealing solution, we will provide what you need as quickly and efficiently as possible.

To find out more information about vulcanized O-rings, please contact Arizona Sealing Devices today.

Viton O-Rings and Sealing Devices Guide

Viton is a versatile, inert alternative material for O-rings, gaskets, and other sealing components. The material is well-regarded for its resistance to chemical damage and its stability in high-temperature and high-pressure environments. Available formulations of Viton offer varying degrees of hardness, enabling its use in products that meet food-grade or medical-grade standards, as well as compounds that can withstand explosive decompression. This versatility makes Viton an ideal choice for fabricating commercial and industrial O-rings that offer long-term reliability in extreme conditions.

Viton Properties

black o rings on black backgroundViton is a synthetic rubber elastomer that can be easily molded or extruded into precise shapes and forms for a wide variety of sealing applications. It typically comes in standard brown and black colors. The material has a hardness range of 50-95 on the durometer hardness scale, with a typical range of 70-75 Shore A. Viton is also inert and retains its properties at temperatures ranging from -20°F to 400°F.

Along with these core characteristics, Viton also resists physical and chemical damage and features excellent tensile strength, ultimately improving its lifespan. It also offers good-to-excellent tensile strength due to its chemical makeup and the high density of the material. Viton’s density is around 1800 kg/m3, compared to other popular rubbers that typically range from 1010 to 1520 kg/m3.

Viton Sealing Device Compatibility

As with all sealants, it’s important to select a material that balances with any extreme environmental factors, harsh chemicals, and other relevant application factors. Viton offers the following resistances:

Physical Properties

  • Abrasion resistance: Good
  • Dynamic resistance: Good-to-excellent
  • Set resistance: Good-to-excellent
  • Tear resistance: Fair-to-good
  • Electrical properties: Fair

Chemical Properties

  • Acid resistance: Excellent
  • General chemical resistance: Good
  • Impermeability: Good
  • Oil resistance: Excellent

Environmental Properties

  • Ozone resistance: Excellent
  • Weather resistance: Excellent
  • Water steam resistance: Fair-to-good

Temperature Properties

  • Cold resistance: Fair
  • Heat resistance: Excellent
  • Flame resistance: Excellent

Viton Sealing Device Applications

Viton O-rings, gaskets, and other sealing devices can be used in a wide range of industrial and commercial applications. These include applications with unique environmental factors, such as:

Viton Sealing Device Applications
  • Vacuumed environments: Viton withstands high pressures and explosive decompression forces, making it ideal for use in many automotive and aerospace systems.
  • Contact with most acids and chemicals: While Viton isn’t suitable for use with acetone and some organic acids, it can withstand solvents, petroleum-based products, and more. Viton gaskets are frequently used in chemical processing centers and pharmaceutical manufacturing plants. It also handles contact with halogenated hydrocarbons, oil, silicone oil, petroleum fuels, and grease for seals in automotive vehicles, aeronautics equipment, and industrial equipment systems.
  • Di-ester lubricants. Viton may be used with di-ester lubricants, which allows Viton O-rings and seals to function well in high-performance systems that require lubrication.
  • Vulcanized. Viton is common material for vulcanized or spliced o-rings. These are ideal for static sealing and are advantageous in this application for molded o-rings which tend to have non-standard measurements.

Some specific applications for Viton O-rings and seals include:

  • Pneumatic seals
  • Bearing isolators that create a barrier against lubricant leaks and contamination
  • Non-contact labyrinth and clearance seals
  • Axial static seals

Choose Viton Sealing Devices From Arizona Sealing Devices

Arizona Sealing Devices supplies high-quality O-rings, gaskets, and sealing solutions made from Viton, nitrile, fluorocarbons, and more. Choosing the proper material is crucial for O-rings and gaskets, especially if they operate in extreme environments or zero-failure applications. We help our customers through every stage of the material selection and manufacturing process.

We are an ISO 9001:2015/AS9120B-certified distributor and have been a leading O-ring supplier since 1989. Contact us today to learn more about our services and our commitment to excellent customer service. You may also browse our catalog to view our O-ring and sealing products.

Silicone O-Rings and Sealing Devices Guide

three colored silicone o rings in a rowSilicone is an elastomer that remains stable, flexible, and non-reactive in extreme conditions, making it ideal for seals, gaskets, and O-rings. O-rings are molded products placed between two mechanical parts to create a tight seal for preventing fluid or gas leakage and keeping out contaminants. Choosing a silicone O-ring provides greater flexibility and performance for a wide variety of applications. With a range of properties and compositions available, you can easily customize your silicone O-rings for any implementation. This could include vulcanized or spliced o-rings as well.

Silicone Properties

Silicone has an extensive range of uses due to its ability to withstand temperature extremes from -58° F to +450° F. Even in very low temperatures where many materials become brittle, silicone remains flexible. Silicone O-rings are extremely clean and do not retain or relay odors or taste, making them highly sought after for food, medical, and semiconductor applications. Some of the other useful properties of silicone include:

  • Resistant to fungal growth
  • Stands up well to hot air, UV, and ozone exposure
  • Withstands weathering
  • Resists damage from engine, transmission, animal, and vegetable oils and fats
  • Compounding can impart qualities of electrical resistance, conductivity, or flame retardancy
  • Possesses a hardness range of 30 to 80 durometer Shore A, with a standard hardness of 70 durometer Shore A
  • Can be compounded to meet FDA, USDA, MIL-STD-413C, MIL-STD-105E, and MIL-I-45208A specifications
Silicone O-Ring Compatability

Silicone O-Ring Compatibility

As with all materials, silicone O-rings have characteristics that are more ideal for some uses and conditions than others. They are best categorized as follows:

  • Recommended Applications: Silicone O-rings are recommended for applications requiring good electrical properties and resistance to heat, cold, ozone, set, weather, acid, chemicals, oil, water steam, and flame.
  • Less Suitable Applications: Silicone O-rings are not recommended for applications that require high levels of tensile strength, impermeability, and significant abrasion, tear, or dynamic resistance.
Silicone O Ring Compatability

Silicone O-Ring Applications

The properties of silicone O-rings allow them to be used across many industries and applications, including but not limited to:

  • Automotive. Used to seal fluids, lubricants, and coolant in fuel and brake systems, engines and transmission components, and automotive air conditioning systems
  • Aviation and defense. Used for sealing applications in aircraft, helicopters, gun systems, and ships
  • Construction and agriculture. Used in heavy-duty equipment and hardware
  • Electronics. Used to seal away from dust and other contaminants that could damage delicate electronic components
  • Food and beverage. Prevents cross-contamination in food and beverage processing equipment and utensils
  • Medical devices. Used in pumps, syringes, filtration devices, and connectors
  • Pharmaceutical. Used in drug production applications and miniature components for laboratory and analytical equipment
  • Semiconductor. Used in fabricating process equipment and integrated circuits
  • Utilities and HVAC. Used for sealing in heating, cooling, sprinkler, drinking water, and compressed air systems  
Silicone O Ring Compatability

Qualified Sealing Experts

When it comes to choosing the right O-ring for your application, material selection is critical. Arizona Sealing Devices has over 30 years of experience in supplying O-rings and other sealing solutions such as caps, plugs, gaskets, and kits in a wide variety of materials. Our talented and highly experienced team extensively researches each product so they can recommend the ideal solution and answer any questions you have about our materials and products. 

We are committed to meeting or exceeding customer expectations in quality, selection, functionality, and customer service. For more information on our inventory, please see our product catalog, or contact us today with any questions.

Buna O-Rings and Gaskets

Buna, otherwise known as Nitrile, Buna-N or NBR, is an incredibly versatile synthetic rubber. The unique properties of this material make Buna an ideal material for O-rings, vulcanized or spliced O-rings, gaskets, and other sealing applications for various industries.

Properties of Buna

black o rings on black backgroundBuna offers many unique properties; making it the sealing industry’s most commonly used material. It is a durable, versatile elastomer that’s typically black in color and resistant to various chemicals, including fuel, oil, diluted acids, alkaline, mineral, vegetable oils, and more. Buna is resistant to abrasion, has a low compression set, and has a high tensile strength ranging from 200 to 3000 psi with 300% elongation at break.

Buna is composed of the copolymer acrylonitrile and butadiene and can be formulated to withstand temperatures ranging from -85°F to 275°F. Its hardness durometer ranges from 40-90 and has a hardness rating of 70 Shore A. These features make Buna O-rings and gaskets commonly found in low temperature military equipment and off-road equipment. 

Buna Sealing Device Compatibility

Buna Sealing Device Applications

To determine if Buna is a right O-ring and gasket material for your intended application, it is important to know its compatibility with different chemicals and environments. Buna’s compatibility levels are as follows:

  • Good to excellent. Oil resistance, dynamic resistance, set resistance, tensile strength
  • Good. Abrasion resistance, cold resistance, heat resistance, impermeability
  • Fair to good. Chemical resistance, water steam resistance
  • Fair. Acid resistance, electrical properties, tear resistance, weather resistance
  • Poor. Flame resistance, ozone resistance 

Buna Sealing Device Applications

Buna’s unique properties and features make it the ideal material for sealing devices in many applications across a wide range of industries, including military, medical, automotive, and aerospace. Some common applications for Buna sealing devices include:

  • Fuel tanks
  • Engines
  • Gear boxes
  • Pneumatics
  • Water/hydraulics
  • Military equipment
  • General aerospace assemblies

Buna’s strong chemical resistance makes it suitable for applications where ordinary rubber cannot be used due to its reactivity with fuels and oils. 

Buna O-Rings, Gaskets, and Other Sealing Devices from AZ Seal

Crafting your O-rings, gaskets, and other sealing devices from the correct material ensures that your equipment’s critical components are safe from damage caused by chemicals and extreme environments. Buna is a highly resistant and versatile synthetic rubber that offers many advantages over ordinary rubbers, making it the most commonly used sealing material for several applications across numerous industries. 

AZ Seal is an ideal supplier of sealing device solutions using Buna as well as a wide variety of other materials to ensure that you have the best possible O-rings, gaskets, and other sealing devices for your specific application. To learn more about our products or to get started on your sealing solution, browse our catalog or contact our experts today. 

O-Ring Materials Guide

Named for their standard circular shape, O-rings are versatile elastomer gaskets that form a tight seal between two mechanical components. However, while O-rings largely look alike and function similarly, there are actually key distinctions that determine where an O-ring may be used. Chief among these considerations is material selection. Despite their similar compositions, elastomers each have variations in their chemical and mechanical properties that influence how they perform at a given sealing task. When purchasing O-rings, it’s critical to consider your application’s needs and limitations rather than searching for a one-size-fits-all seal.

In this guide, we consider common O-ring materials in detail, including their strengths, limitations, and common applications. If you still have questions about after reviewing this material selection guide, we encourage you to contact our team at Arizona Sealing Devices, or browse our selection of O-rings.

O-Ring Materials: Strengths, Limitations, and Applications

At Arizona Sealing Devices, we work with a variety of elastomers to produce O-Rings. Here are the materials we use most frequently:


Among the most common elastomers used in O-ring manufacturing, Nitrile is a synthetic rubber unique for its chemical resistance properties. Whereas other rubbers often react with fuel and oil, nitrile is resistant to these substances, as well as many diluted acids and alkalines. As such, nitrile/Buna-N O-rings are the ideal choice for automotive, aerospace, and marine fueling. High tensile strength and thermal resistance enhance its utility in the aerospace and automotive industries. Despite its favorable chemical resistance characteristics, nitrile should not be exposed to ethers, esters, ketones, or chlorinated hydrocarbons.



Aflas is another elastomer that offers a combination of chemical, thermal, and electrical resistance properties, resisting acids, bases, and heat up to 446°F. Like nitrile, it is popular in oil, aerospace, and general industrial environments. However, Aflas should not be used in direct contact with automotive fuels because it swells more than comparable elastomers.


Butyl is the classic choice for vacuum-sealing, providing extremely low permeability to gases. Its other benefits include resistance to ozone and sunlight, as well as good shock-dampening capabilities. Due to its shock-absorbing properties and chemical resistance, butyl is also used in hydraulics applications—especially those that use synthetic lubricants. However, ethylene propylene has largely supplanted butyl due to its enhanced durability.

Ethylene Propylene

A modern alternative to butyl, ethylene propylene exhibits low gas permeability alongside excellent heat, weather, and ozone resistance. These characteristics make it one of the most versatile elastomers for O-ring seals. Ethylene propylene is often used outdoors where weather resistance is a concern, as well as in automotive cooling and brake systems. The material’s primary limitation is a susceptibility to hydrocarbons.

Fluorocarbon (Viton®)

Offering outstanding chemical and high-temperature resistance, fluorocarbon O-rings are among the most durable and versatile available. They are particularly valuable in aircraft engines and automotive fuel handling systems because they resist swell in high-octane and oxygenated fuels. They also have improved resistance to amine-based oil protectants. Fluorocarbon’s primary limitation is an intolerance to low temperatures and certain chemicals, such as ketones, amines, low molecular weight esters, and ethers.


Fluorosilicone is a saturated rubber with excellent extreme-temperature stability, making it a popular material in aerospace applications. Having both thermal and chemical resistance properties, fluorosilicone is also becoming popular for general-purpose O-rings, especially for outdoor applications. However, fluorosilicone is not a good choice for dynamic sealing of any kind due to its low strength and limited abrasion-resistance. 

Hydrogenated Nitrile

Hydrogenating nitrile yields a more highly saturated chemical structure with correspondingly higher strength and chemical resistance. Hydrogenated nitrile O-rings perform well in oil- and fuel-handling applications, as well as general industrial use. Like nitrile, hydrogenated nitrile has excellent thermal properties, sealing at temperatures from -85°F to 350°F. Like standard nitrile, hydrogenated nitrile should not be used with ethers, esters, ketones, and chlorinated hydrocarbons.

Silicone Rubber

Although silicone is well-known for medical-grade and FDA-compliant sealing applications, silicone rubber is also a solid choice for extreme temperature static sealing due to its heat and cold resistance. Silicone rubber also holds up to weather, ozone, and acid exposure, although its low abrasion resistance limits its utility to static sealing applications.


Neoprene is an oil-resistant, weather-resistant, and ozone-resistant alternative to natural rubber that finds frequent use in the transportation industry. Resistant to Freon® and ammonia, neoprene is also a good choice for sealing refrigerators. As general O-ring material, however, neoprene is often cost-prohibitive compared to nitrile, which offers similar properties at a lower cost.

Polyurethane, Cast

Cast polyurethane stands out for its abrasion resistance, tensile strength, and shock absorption, though it also boasts resistance to many chemicals, including ozone, oils, and greases. Cast polyurethane O-rings offer excellent performance in high-pressure hydraulic systems, as well as in wheels and other dynamic systems. Polyurethane should not be exposed to strong acids, bases, or brake fluids, limiting some of its potential transportation applications despite the material’s capacity to carry heavy loads.

Polyurethane, Millable

Millable polyurethane is resistant to high-pressure hydraulic fluids, abrasion, oil, grease, cracking, and many chemicals. Like cast polyurethane, it does well under dynamic, heavy loads, even when used outdoors. Compared to cast polyurethane, it has a lower tensile strength and weakens at high temperatures. 


Kalrez features exceptional chemical resistance, and there’s virtually no industrial chemical that will cause it to degrade (although Kalrez O-rings will swell in the presence of certain solvents). Being nearly as inert as Teflon, Kalrez is one of the best options for chemical processing, oil and gas, and semiconductor manufacturing.  


PTFE yields some of the toughest O-rings on the market with an outstanding temperature range of -300° to 450°F. The trade-off is that PTFE is difficult to install, having very limited elastic memory and poor tear resistance. The latter property also means that PTFE should be limited to static loads or slow dynamic loads.

Quality O-Rings from Arizona Sealing Devices

Without extensive experience in sealing, it can be difficult to determine which elastomer is right for a given project. The experts at Arizona Sealing can help.

Arizona Sealing Devices, Inc. has extensive experience with all of these elastomers, and we take pride in matching our clients to the materials that will suit them best over time. An O-ring supplier since 1989, we have since become an ISO 9001:2015-certified distributor of a broader range of sealing products, including caps, gaskets, plugs, and seal kits. We’ve also worked with satisfied customers from virtually every industry, developing a nuanced understanding of the practical limitations of different sealing applications. As a result, our clients return to us again and again for guidance and reliable elastomer products.

To learn more about Arizona Sealing’s personalized service and extensive product line, request a quote today.

Guide to O-Ring Selection

O-rings are elastomeric and donut-shaped gaskets designed to create fluid-tight seals between mated parts within a fluid system. Although simplistic in design and function, these components perform a critical role. When used correctly in fluid handling and processing systems, they ensure process liquids and gases remain inside the proper areas and potential contaminants stay outside of sensitive areas. Some of the typical industries that regularly make use of O-rings include transportation, medical, electronics, oil and gas, and food and beverage. 

The following article provides a comprehensive overview of O-rings—including their design considerations, types available, materials used, manufacturing processes, and industrial applications—to aid in proper selection. 

What Are O-Rings?

O-Ring Selection Factors

By technical definition, all O-rings can be considered gaskets, but not all gaskets can be regarded as O-rings. Although both create seals that prevent fluids from leaking in or out of the area between two mated components, there are critical differences in their design and performance. One of the primary distinctions between the two is the shape of flange they accommodate; gaskets require flanges with flat surfaces, while O-rings need ones with a channel or groove. For the latter, this design element helps avoid blowout in high-pressure environments in which other gaskets would likely fail.

When properly sized and compressed within the groove between two mated components, O-rings form tight seals that prevent the escape of gases and liquids. They are available in several variations to suit the needs of a wide range of applications.

Design Considerations for O-Rings

When choosing an O-ring for an application, the following design elements should be considered:

  • Size and shape: the size and shape of an O-ring must suit the size and shape of the intended groove to ensure proper compression and sealing is achieved
  • Material: the O-ring material must withstand the operating and environmental conditions of the application
  • Static vs. dynamic: static O-rings are used for creating seals between stationary parts, while dynamic O-rings are used for moving parts

Types of O-Rings

As indicated above, many design factors affect the sealing performance of an O-ring. Some of the common types of O-rings available and their applications include:

  • Round: O-rings with round cross-sections are extremely versatile and provide multi-directional sealing under minimal compressive force.
  • Square: Square O-rings provide superior sealing capabilities, even in the presence of surface defects.
  • Quad: Quad O-rings have a four-lobed design that allows for twice as much sealing power as round O-rings under relatively low compressive pressure.

Common O-Ring Materials

The type of material used to create an O-ring significantly influences its ability to perform reliably when used in the intended application. Typical elastomeric materials used in the construction of O-rings include:

  • AFLAS®
  • Buna/Nitrile
  • Butyl
  • Ethylene Propylene
  • Fluorocarbon
  • Fluorosilicone
  • Hydrogenated Nitrile
  • Kalrez®
  • Neoprene
  • Polyurethane
  • PTFE
  • Silicone

When selecting a material for an O-ring, there are several considerations to keep in mind, such as:

  • Gland type and fill: The opening (gland) into which the O-ring is installed must allow for the appropriate level of compression and gland fill percentage to avoid O-ring failure.
  • Stretch: The material should exhibit the appropriate amount of circumferential stretching to fit properly within the groove
  • Compression squeeze: The material should maintain an appropriate level of compression squeeze (deformation) under the expected pressure level.
  • Industry standards: Some industries require the use of materials that exhibit specific properties, such as food-grade or military-grade.

To learn more about selecting the right o-ring material for your application, read our o-ring materials guide.

How Are O-Rings Made?

The manufacturing technique used to create an O-ring largely depends on the material employed and the performance level required. The most common O-ring production methods include:

  • Compression molding: The material is placed into and enclosed within an open heated mold cavity, compressing and shaping it into the O-ring shape.
  • Transfer molding: The material is placed under intense pressure, forcing it into a mold cavity of the O-ring shape.
  • Injection molding: The material is heated and injected into the cavity of a mold. Once cooled, it maintains the desired O-ring shape.
  • Extrusion: The material is heated and forced through a die with an opening that forms it into the desired O-ring shape as it exits.

Applications of O-Rings

When selected and used properly, O-rings form fluid-tight seals in a wide range of equipment and systems, even when exposed to high-temperature and high-pressure conditions. Some examples of typical use cases include:

  • Static axial systems: In static axial systems, the O-ring design should consider the pressure direction (inward or outward) as it affects the inner and outer groove diameters and widths required for optimal sealing.
  • Reciprocating dynamic systems: In reciprocating hydraulic or pneumatic systems, the diameter of the O-ring depends on whether the O-ring is used for short stroke applications (smaller diameter preferred) or long-stroke applications (thicker cross sections preferred).
  • Rotary systems: O-rings can function as reliable rotary shaft seals under the right conditions, but the correct O-ring compound for the application’s speed (feet per minute) must be selected.

The versatility of O-rings makes them well-suited for use in a diverse set of industries, such as:

  • Chemical processing
  • Electronics
  • Energy
  • Fluid power
  • Food and beverage
  • Medical
  • Oil and gas
  • Transportation
  • Water systems

O-Ring Seals from Arizona Sealing Devices

Founded in 1989, Arizona Sealing Devices is a distributor of high-quality standard and specialized sealing products. Equipped with over three decades of industry experience and an ever-expanding product selection, we can ensure that each O-ring variable (shape, size, material, etc.) and its compatibility with the operating system is carefully considered when choosing a sealing solution. 

We offer an extensive O-ring catalog, which encompasses a variety of material compounds and durometers, sizes (for inner, outer, and cross-sectional diameters), performance characteristics, and industry compliances (e.g., Mil-spec, food-grade, and metric). As an ISO 9001:2015 and AS9120B certified company, we guarantee the delivery of a quality and dependable product solution that meets all relevant regulatory requirements and satisfies your sealing needs. 

For additional information on O-rings or assistance choosing one for your unique application, contact us today.

How to Install O-Rings

O-rings are a vital tool for ensuring the effective operation of numerous vehicles, appliances, and other everyday items. Proper O-ring installation creates a strong seal, allowing the product to function efficiently without leakage.

What is an O-Ring?

While they may seem simple, O-rings actually serve an important purpose. This round, often rubber ring helps to prevent leaks and product failures. They do this by creating a seal between parts, which stops air and fluid from moving around within the final product. O-rings are generally designed to be installed within a groove and then compressed. They come in a variety of different materials, which can make material selection an important consideration.

How to Install an O-Ring

Due to their vital function, it’s important to know exactly how to install an O-ring without damaging it. The first step to proper installation is to choose an appropriate lubricant and use it to lightly coat your O-ring.

Once you have properly lubricated the O-ring, you should make sure to cover any sharp edges on the parts that may come into contact with the O-ring. This helps prevent the O-ring from being damaged during the installation process. It’s also important to be cognizant of how much you stretch the O-ring during installation—it should stretch no more than 50%, and any stretching should be performed uniformly rather than just one side.

After you have successfully slid the O-ring onto the shaft, the final step is to ensure that the seal is not twisted inside the groove. If installing a backup O-ring, make sure to do it on the low pressure side of the system so that the high pressure will push the O-ring against the backup rather than away from it.

Tips for O-Ring Installation

Here are some tips to ensure a successful O-ring installation: 

  • Lubricate the threads. As the shaft consists of threading, it’s easy for the rubber seal to tear during installation. This can be avoided by covering the threads with masking tape and/or lubricant.
  • Cover sharp corners. Jagged edges can cause tears in the O-ring — and even a tiny tear can effectively break the seal.
  • Stretch the O-ring evenly. Minimizing stretching and ensuring that the O-ring is evenly stretched on all sides helps create a stronger final seal.
  • Slide, don’t roll. During installation, make sure to never roll the O-ring down the shaft, as this can cause damage. Instead, lubricate the O-ring so that it can easily slide down the shaft.
  • Assemble so that the female component has a radius around the corner. Placing the component’s lead inside the chamfer increases the safety of the O-ring.


Using O-Ring Lubricants

Choosing the appropriate lubricant is a vital step in the proper installation of an O-ring. There are many common types of lubricants, including:

  • Petroleum distillates
  • Soap and water
  • Solvents
  • Ester based lubricants

While there are many choices, however, they are not all created equal. Certain types of lubricant will actively damage the O-ring or cause safety issues. Solvents, for example, are not a particularly effective lubricant. They can be flammable, pose health risks, and contain high VOCs. 

Petroleum distillates are another common, but less than ideal choice, as they frequently cause rubber to dry out or swell. While soap and water may be safe, they are not especially effective. They may even reactivate when wet, which can significantly reduce the efficacy of the O-ring. 

The best choice for O-ring lubricant is almost always an ester based product. This type of lubrication is safe for workers and environmentally friendly. It also drastically reduces friction and offers effective temporary lubrication during the installation process.

Partner With the Qualified Sealing Experts

Although O-rings are a fairly simple tool, they serve a vital function in a myriad of products. Understanding the fundamentals of how to properly install an O-ring can ensure that your project will be successful.

At Arizona Sealing Devices, we’ve been specializing in high-quality sealing devices since 1989. Our team of experts is well-versed in helping clients find the best solution for their unique needs. To learn more about our offeringscontact us or request your quote today.