2427 Decatur Ave, Fort Worth, TX 76106, US +1 817 614 1836 ask@rubberxperts.com
Blue rubber O-ring sealing ring used for hydraulic and industrial systems

Rubber O-Rings

Rubber O-rings are circular seals designed to fit snugly between parts, preventing the flow of liquids, gases, and particles under pressure. Rubber Xperts offers a variety of durometers, diameters, and cross-sections, ensuring a suitable compound for applications like hydraulic cylinders, plumbing fittings, and aerospace fuel lines, all built for durability and minimal maintenance.

A rubber O-ring is a torus-shaped seal made from a single elastomer that compresses into gaps between surfaces, adapting to minor irregularities and vibrations. This unique behavior distinguishes O-rings from flat gaskets, making them the preferred choice in engines, pumps, valves, and various rubber products.

10% discount for bulk orders over $1,000

Types of Rubber O-Rings We Produce

We produce O-rings in a dozen elastomer compounds, each suited to a different combination of temperature, chemical exposure, and mechanical load. The cards below break
down what each material is built for, so you can match the compound to your application before you order.

silicone o-rings for food-grade and medical applications

Silicone O-Rings

Silicone O-rings are molded from VMQ elastomer prized for performing reliably across an unusually wide temperature range while remaining safe for food, medical, and electronic contact. Whether the application runs bitterly cold or intermittently hot, silicone O-rings hold their seal without cracking or losing flexibility.

  • Applications: Food and beverage equipment, medical devices, electronics enclosures, HVAC, aerospace components
  • Materials: Silicone (VMQ)
  • Temperature Resistance: -60°C to 200°C (short-term up to 230°C)
  • Hardness: 40 – 80 Shore A (most commonly 50–70)
  • Sizing: AS568 and metric ISO 3601 standard sizes, custom sizes available
EPDM rubber o-rings for automotive and HVAC systems

EPDM O-Rings

EPDM O-Rings are built from ethylene propylene diene monomer rubber, a compound that resists water, steam, and outdoor weathering far better than most general-purpose elastomers. For potable water systems, HVAC, and outdoor seals, EPDM O-Rings stay pliable and leak-free season after season.

  • Applications: Potable water systems, HVAC equipment, outdoor and weatherproof seals, brake systems using non-petroleum fluids
  • Materials: EPDM (ethylene propylene diene monomer)
  • Temperature Resistance: -50°C to 150°C
  • Hardness: 40 – 90 Shore A (most commonly 60–70)
  • Sizing: AS568 and ISO 3601 standard sizes, custom sizes available
Neoprene o-rings with chemical resistance for industrial use

Neoprene O-Rings

Neoprene O-Rings, made from chloroprene rubber, balance moderate oil resistance with solid weathering and flame resistance, making them a dependable general-industrial choice. When a seal needs to handle everyday exposure to oils, ozone, and outdoor conditions without a premium price tag, neoprene O-rings are the practical fit.

  • Applications: Refrigeration systems, general industrial machinery, outdoor equipment, moderate oil and fuel exposure
  • Materials: Neoprene (CR – chloroprene rubber)
  • Temperature Resistance: -40°C to 120°C
  • Hardness: 40 – 85 Shore A (most commonly 60–70)
  • Sizing: AS568 and ISO 3601 standard sizes, custom sizes available
Fluorosilicone o-rings for aerospace and fuel applications

Fluorosilicone O-Rings

Fluorosilicone O-rings combine silicone's extreme-temperature flexibility with meaningful fuel and oil resistance, a pairing few compounds offer. Fluorosilicone O-rings excel in applications where standard silicone is inadequate, providing reliable sealing for aerospace and military systems that require durability against both cold temperatures and direct exposure to fuel.

  • Applications: Aerospace and military fuel systems, aircraft hydraulics, low-temperature fuel-exposed seals
  • Materials: Fluorosilicone (FVMQ)
  • Temperature Resistance: -70°C to 175°C (short-term up to 200°C)
  • Hardness: 40 – 80 Shore A (most commonly 60–70)
  • Sizing: AS568 and ISO 3601 standard sizes, custom sizes available
FKM Viton o-rings for high-temperature chemical resistance

FKM O-Rings

FKM O-Rings (often known by the brand name Viton) are the go-to fluorocarbon compound for sealing against aggressive fuels, oils, and chemicals at sustained high temperatures. FKM O-rings keep their seal integrity long after standard nitrile degrades in demanding chemical-processing and fuel-system environments.

  • Applications: Fuel systems, chemical processing equipment, high-temperature oil seals, industrial hydraulics
  • Materials: Fluorocarbon (FKM)
  • Temperature Resistance: -20°C to 200°C (special low-temperature grades to -40°C)
  • Hardness: 60 – 90 Shore A (most commonly 75)
  • Sizing: AS568 and ISO 3601 standard sizes, custom sizes available
HNBR hydrogenated nitrile o-rings for automotive applications

HNBR O-Rings

HNBR O-Rings are hydrogenated nitrile compounds engineered for higher heat and abrasion resistance than standard nitrile offers. Automotive and hydraulic systems that push seals harder and hotter than average rely on HNBR O-Rings to keep running without unplanned downtime.

  • Applications: Automotive engine seals, hydraulic systems, oilfield equipment, industrial machinery
  • Materials: Hydrogenated nitrile (HNBR)
  • Temperature Resistance: -40°C to 150°C
  • Hardness: 50 – 90 Shore A (most commonly 70–80)
  • Sizing: AS568 and ISO 3601 standard sizes, custom sizes available
Buna-N NBR nitrile o-rings for oil and fuel systems

Buna (NBR) O-Rings

Buna (NBR) O-Rings are the industry's workhorse nitrile compound, offering solid resistance to oils, fuels, and hydraulic fluids at a cost-effective price point. For everyday automotive and hydraulic sealing where extreme conditions aren't in play, Buna (NBR) O-Rings remain the most widely specified choice.

  • Applications: Automotive fuel and oil seals, hydraulic systems, general industrial sealing
  • Materials: Nitrile (NBR)
  • Temperature Resistance: -40°C to 120°C
  • Hardness: 40 – 90 Shore A (most commonly 70)
  • Sizing: AS568 and ISO 3601 standard sizes, custom sizes available
Polyurethane o-rings with abrasion resistance for dynamic sealing

Polyurethane O-Rings

Polyurethane O-rings stand out for abrasion resistance and load-bearing toughness beyond standard rubber compounds. In pneumatic and hydraulic systems where seals face constant friction and mechanical wear, polyurethane O-rings outlast softer elastomers by a wide margin.

  • Applications: Pneumatic systems, hydraulic equipment, heavy machinery, high-wear and abrasive environments
  • Materials: Polyurethane (AU/EU)
  • Temperature Resistance: -30°C to 80°C (short-term up to 100°C)
  • Hardness: 70 – 95 Shore A
  • Sizing: AS568 and ISO 3601 standard sizes, custom sizes available
Santoprene thermoplastic elastomer o-rings for automotive use

Santoprene O-Rings

Santoprene O-Rings are thermoplastic vulcanizates that deliver rubber-like sealing performance with better resistance to repeated compression cycling and UV exposure than many traditional compounds. For outdoor equipment and appliances that see constant thermal cycling, Santoprene O-Rings hold their shape and seal longer.

  • Applications: Outdoor equipment, household appliances, water-handling components, general fluid sealing
  • Materials: Polyurethane (AU/EU)
  • Temperature Resistance: -60°C to 135°C
  • Hardness: 55 – 90 Shore A
  • Sizing: AS568 and ISO 3601 standard sizes, custom sizes available
Butyl rubber o-rings for vacuum and gas sealing applications

Butyl Rubber O-Rings

Butyl rubber O-rings offer some of the lowest gas permeability elastomers, making them the natural choice wherever a seal holds against air or gas migration rather than aggressive chemicals. Vacuum systems and pressurized containers depend on butyl rubber O-rings to maintain that seal over long service life.

  • Applications: Vacuum systems, pressurized gas containers, insulating glass seals, chemical drum seals
  • Materials: Butyl rubber (IIR)
  • Temperature Resistance: -40°C to 120°C
  • Hardness: 40 – 80 Shore A
  • Sizing: AS568 and ISO 3601 standard sizes, custom sizes available
Natural rubber o-rings for water service and general sealing

Natural Rubber O-Rings

Natural rubber O-rings deliver elasticity and tear resistance that synthetic compounds often can't match, making them ideal for seals that face constant flexing or shock loading rather than chemical exposure. Where abrasion and vibration are the main concerns, natural rubber O-rings hold up longer than most alternatives.

  • Applications: General mechanical sealing, vibration and shock dampening, abrasion-heavy applications
  • Materials: Natural rubber (NR)
  • Temperature Resistance: -50°C to 80°C
  • Hardness: 30 – 90 Shore A
  • Sizing: AS568 and ISO 3601 standard sizes, custom sizes available

AEM O-Rings

AEM O-Rings are ethylene acrylic elastomer seals purpose-built for automotive powertrain and drivetrain applications exposed to hot transmission and axle fluids over long service intervals. Where standard nitrile would harden and crack under sustained heat, AEM O-Rings keep sealing reliably.

  • Applications: Automotive powertrain seals, transmission and axle housings, hot-oil-exposed components
  • Materials: Ethylene acrylic elastomer (AEM)
  • Temperature Resistance: -40°C to 150°C (short-term up to 175°C)
  • Hardness: 50 – 85 Shore A
  • Sizing: AS568 and ISO 3601 standard sizes, custom sizes available
Bulk O-Ring Orders

Buy High-Quality Rubber O-Rings in Bulk Today From Rubber Experts Inc

Place Your Order

Your Custom Rubber O-Rings Journey - From Selection to Delivery

Ordering a custom O-ring doesn't have to mean guessing at a spec sheet. Here's how the process runs from your first call to the part landing on your dock:

01

Consultation and Selection

We start by reviewing your application. Liquids or gases, temperature range, pressure, and movement (static or dynamic) then narrow down the compound and size that fit.

02

Quote and Engineering

Once the material and dimensions are set, our team engineers the O-ring to your tolerances and provides a firm quote covering material, tooling (if needed), and lead time.

03

Custom Manufacturing

Your O-rings are made to spec in-house, with in-process checks on dimensions and cure to keep every part within tolerance.

04

Quality Control and Shipping

Finished parts go through final inspection against your spec before they're packed and shipped, with documentation available on request for regulated applications.

Total Turnaround: 7-10 business days | Express bulk O-rings available in 7-10 days

What Are Rubber O-Rings and Why Are They Essential?

Rubber O-rings are circular elastomer seals designed to fit into grooves and prevent the passage of liquids or gases. Also known as O-ring seals or O-ring gaskets, these flexible sealing elements create airtight and watertight barriers by compressing between two surfaces under pressure or movement.

Their primary function is maintaining leak-proof connections in industries ranging from plumbing and automotive to manufacturing and chemical processing. According to a Research Nester Report, the O-ring market in the aerospace equipment segment is expected to gain a 52% share by 2037, highlighting the critical role O-rings play in fueling industrial growth.

The elastomeric properties of O-rings allow them to deform and fill gaps while returning to their original shape, ensuring consistent sealing performance under varying conditions. This adaptability, combined with their cost-effectiveness and ease of installation, makes them indispensable components across countless applications.

What Materials Are Used in Rubber O-Ring Manufacturing?

O-rings are molded from synthetic and natural elastomers, chosen for how they respond to heat, chemicals, and mechanical stress in the sealing environment. The same underlying compounds show up across our broader range of gasket materials, since O-rings and gaskets are frequently molded from the same rubber families. The difference is mostly in the cross-sectional shape rather than the chemistry. That’s why choosing between nitrile, silicone, EPDM, or fluorocarbon for an O-ring involves the same trade-offs in temperature range, oil resistance, and compression set that come up when specifying flat or molded gaskets.

How to Choose the Best Rubber O-ring Material

Picking the right compound comes down to five factors:

Temperature Requirements

Check both the continuous operating temperature and any short-term spikes the seal will see. Silicone and fluorosilicone handle wide temperature swings well, while standard nitrile compounds narrow that range considerably.

Chemical Compatibility

Match the compound to whatever fluid or gas it will contact. FKM and HNBR resist a broad range of oils and fuels; EPDM resists water and steam but degrades quickly in petroleum-based fluids.

Pressure Conditions

Higher system pressure needs a harder durometer and tighter dimensional control to prevent extrusion through the mating gap, particularly in hydraulic and pneumatic applications.

Dynamic vs Static Use

Static seals (no relative movement between surfaces) have more flexibility in compound choice than dynamic seals, which see repeated friction and need better abrasion and compression-set resistance to avoid premature wear.

Regulatory Compliance

Applications in food, pharmaceutical, or drinking-water systems require compounds certified to standards like FDA, NSF, or USP Class VI. Confirm certification requirements before finalizing material choice.

How to Determine Rubber O-Ring Sizes

To determine the rubber o-ring sizes, consider the following O-ring dimensions:

measuring O-ring size for precise fitting in sealing applications
  • Inner Diameter (ID): Distance across the inside of the O-ring, determining fit around grooves or shafts
  • Outer Diameter (OD): Distance across the O-ring's exterior, ensuring proper housing compatibility
  • Cross-Section (CS): Thickness of the O-ring's circular body, affecting compression requirements

Standard Sizing Systems:

Most O-rings in North America follow AS568 standard sizing, which defines a fixed set of inner diameter (ID) and cross-section (CS) combinations by dash number. Metric applications typically use ISO 3601 sizing instead, so check which system your equipment specifies before ordering.

Measuring Tools:

Use a caliper to measure the inner diameter, outer diameter, and cross-sectional thickness of an existing O-ring, or measure the groove dimensions directly if you're sizing for a new design. When in doubt, send us the groove specs, and we'll confirm the right dash size.

The Benefits of Rubber O-Rings

The key features and benefits of the rubber o-rings Rubber Xperts Inc sells are highlighted below:

Reliable Leak Prevention Under Pressure

Because an O-ring compresses and rebounds against the mating surfaces, it maintains a consistent seal even as pressure and temperature fluctuate, cutting down on leak-related downtime and fluid loss.

Cost-Effective and Easy to Install or Replace

O-rings are inexpensive relative to other seal types and require no special tools to install, which keeps both initial part cost and maintenance labor low.

Wide Size Availability in Standard and Metric Dimensions

With standardized sizing systems covering most common applications, replacement parts are easy to source without a custom order in the majority of cases.

Chemical & Heat Resistance for Harsh Environments

The right compound choice lets an O-ring hold its seal in the presence of aggressive chemicals or sustained high heat that would degrade lesser materials.

Versatile for Multi-Industry Applications

The same basic design scales from tiny electronics seals to large industrial hydraulic cylinders, making O-rings adaptable across automotive, aerospace, plumbing, and manufacturing use cases.

How to Install Rubber O-Rings

To install Rubber O-rings, consider the following steps:

1

Step 1: Inspection and Preparation

Clean the groove and surrounding area thoroughly, removing debris, old lubricant, or metal shavings. Inspect the O-ring for cuts, cracks, or deformation that could compromise sealing integrity.

2

Step 2: Lubrication Application

Apply a compatible lubricant to reduce friction during installation. Use silicone-based grease for general applications or synthetic O-ring oil for specialized requirements. Ensure lubricant compatibility with the O-ring material and system fluids.

3

Step 3: Careful Positioning

Position the O-ring without excessive stretching or twisting. Use plastic installation picks from O-ring mounting kits to avoid damage. Roll the O-ring into place rather than pulling aggressively to prevent overstretching.

4

Step 4: Proper Seating

Ensure even seating in the groove with no pinching or bulging. Check alignment to maintain consistent compression across the entire circumference.

5

Step 5: System Testing

Test the assembly under operational conditions to verify sealing integrity. Perform pressure testing according to manufacturer specifications to confirm reliable performance.

The compression guidelines are listed below.

Static Applications
For non-moving seals, target 20–30% compression of the O-ring's cross-section. This range gives a firm seal without overstressing the material over long dwell times.
Dynamic Applications
Where the seal experiences relative motion, keep compression lower, typically 10 – 20%, to reduce friction and wear while still maintaining seal contact.
Over-compression
Squeezing the O-ring beyond its recommended range accelerates compression set, causing the ring to lose its rebound and leak prematurely, and can also extrude the material into the mating gap.
Under-compression
Too little compression leaves gaps at the sealing interface, especially as the material ages or temperature drops, leading to slow leaks that often go unnoticed until failure.

To maintain rubber O-rings, follow the steps below.

Inspection Schedule
Check O-rings during any scheduled maintenance on the equipment they're installed in, and inspect immediately after any disassembly, before reinstalling or replacing.
Cleaning Procedures
Wipe seals and grooves clean of old lubricant, debris, and residue with a lint-free cloth before reinstalling; avoid solvents that aren't compatible with the O-ring's compound.
Lubrication Maintenance
Apply a compound-compatible lubricant during installation and, for dynamic seals, at scheduled service intervals to reduce friction wear and ease future disassembly.
Replacement Indicators
Replace an O-ring if you see flattening, cracking, hardening, swelling, or any visible nicks. These all signal the material has lost the elasticity needed to maintain a seal.

The common issues linked to rubber O-rings are listed below.

Premature Wear
This often results from improper material selection, inadequate lubrication, or misalignment. To prevent this, verify material compatibility and installation procedures.
Chemical Degradation
This occurs when the O-ring material is incompatible with system fluids. To prevent this, conduct compatibility testing and select appropriate materials.
Extrusion Failure
This occurs under high pressure when O-rings lack adequate support. To fix this, install backup rings or redesign groove specifications.
Temperature Damage
This manifests as hardening or softening beyond material limits. To fix this, select materials with appropriate temperature ratings for the application.

To test rubber O-rings' performance and quality, consider the following options:

Pressure Testing
O-ring seals were tested under simulated operating pressure to confirm they hold without leaking or extruding at the rated pressure range.
Chemical Compatibility Testing
Samples are exposed to the target fluid or gas over time to check for swelling, softening, or degradation before a compound is approved for that application.
Temperature Cycling
O-rings are cycled through the expected operating temperature range to confirm they retain flexibility and sealing force at both the high and low ends.
Compression Set Testing
A sample is compressed for a set period, then released to measure how much of its original height it recovers. A lower compression set means a longer functional life under load.

Explore Related Categories and Accessories

O-rings are rarely used alone, as they are paired with related components. Browse our other rubber product lines: rubber gaskets, rubber seals, rubber hoses,
rubber pipes, rubber extrusions, and rubber mounts, or reach out to our team if you need a part matched to an existing assembly.

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Frequently Asked Questions About Rubber O-Rings

Here are some frequently asked questions about rubber O-rings to help you find the answers you need.

The main difference between an O-ring and a seal is that an O-ring is a specific type of circular sealing element, while a seal is a broader category encompassing various shapes and designs for containing fluids or gases.

You should use Rubber O-rings when the application requires a simple, versatile, and leak-proof solution for sealing under dynamic or static conditions. Conversely, Gaskets are better suited for flat surfaces or irregular shapes requiring a broader sealing area. Rubber O-rings are ideal for pressure systems and fluid containment, while gaskets excel in applications like machinery gaskets or flanged connections.

Yes, rubber O-ring seals can be made from eco-friendly materials by using sustainable rubber compound types derived from natural or recycled sources. Natural rubber or biodegradable alternatives are formulated to meet specific sealing needs, although they might have chemical or heat resistance limitations compared to synthetic rubbers like Viton (FKM). These eco-friendly solutions are increasingly popular in industries prioritising sustainability without compromising seal performance tracking.

Viton/FKM and EPDM O-rings perform best in chemical-heavy environments. Viton excels against solvents and fuels, while EPDM is suitable for water, steam, and some mild chemicals.

Viton/FKM is the most reliable for solvents and fuels, while NBR is suitable for oils and standard fuels but not for harsh chemicals.

Yes. Silicone O-rings can tolerate extreme cold (-60°C), and Viton/FKM can handle up to 200°C or more.

EPDM and Neoprene O-rings are excellent for UV, weather, and marine exposure.

Inspect quarterly for critical systems and replace annually or sooner if exposed to high pressure, heat, or chemicals.

Yes. Rubber Xperts Inc offers custom O-rings and seals for regulated industries and can meet ISO, ASTM, and FDA requirements.

Common causes include over-compression, chemical attack, heat degradation, and improper storage. Use compatible materials and follow installation best practices.

Yes. Store in a cool, dry, and dark place, away from UV exposure, ozone, or chemical vapors.

Yes. We provide bulk supply and OEM support with competitive pricing for industrial buyers.

It’s not recommended. O-rings may deform or pick up debris; replacing them ensures a reliable seal.

Measure the inner diameter (ID), outer diameter (OD), and cross-section using a caliper or O-ring sizing chart.

Yes. Silicone and Viton/FKM O-rings handle the highest temperature ranges.

Replacement depends on material and application. In standard conditions, annual inspection and replacement are recommended.

Yes. Contact us for custom O-ring kits, bulk options, and special size orders.

Need Custom O-Rings for Your Application?

Tell us your size, material, quantity or application requirements and our team will provide a competitive quote.

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