O-ring seals are deceptively simple components — yet when they fail, the consequences can be significant: leaks, equipment damage, delays, even safety hazards. From the infamous Challenger disaster to everyday industrial downtime, many failures can be traced back to mistakes in material choice, design, or installation.
In this guide, we’ll show you how to make an O-ring seal better by addressing:
- Why seals fail (so you can prevent similar issues)
- Practical, actionable tips for installation, maintenance, and material choice
- Common pitfalls to avoid
By implementing these best practices, you’ll enhance reliability, reduce costs, and get better lifetime performance from your O-ring seals.
Lessons from the Challenger: The Cost of O-Ring Failure
Perhaps the most famous O-ring failure in history is that of the Challenger space shuttle, which ended the lives of seven NASA astronauts in January 1986. In the shuttle’s right rocket booster, a seal failed at the aft field joint that led to the spacecraft exploding. It was later found that the O-ring didn’t have the capability to perform correctly at lower temperatures, so it failed to seal fully.
Investigators theorized that cold temperatures at launch time and frozen water within the rocket motor’s joints resulted in O-rings that didn’t return to their correct shapes before launch. This O-ring failure resulted in the joint along the right rocket booster failing as heated; combustible gases caused blow-by and erosion. The resulting domino effect led to the Challenger’s explosion 28 seconds after launch.
While O-ring failures don’t normally result in loss of life, their failure can often damage machinery and cause production delays. Knowing how to improve an O-ring seal will also make an application safer for everyone involved. For those dealing with machinery or equipment that relies on O-rings to operate properly, it’s important to understand what makes them seal so they won’t fail unexpectedly.
Why O-ring Seals Fail
Before learning how to make an O-ring seal better, it’s important to understand why seals fail in the first place. Generally, seals stop working because they fail or wear out. Often preventative maintenance programs that utilize regular inspections will prevent failures by replacing old seals before they completely wear out and fail. However, sometimes seals fail for reasons other than natural wear and tear.
The primary culprit for seal failure is human error emanating from using the wrong seal for the application, as is what evidently happened to the Challenger space shuttle. This is especially true for seals used to join components. That’s why it’s always important to use seals intended for use with a specific component. However, many other things can cause seal failure. Understanding the symptoms and what to look for can help those tasked with correcting such problems.
The more common types of seal failure, along with ways to fix or prevent them, include:
Abrasion: Signs of abrasion include scrapes or loose particles on the surface of the seal. While this could result from high temperatures, poor surface finish, or a rough sealing surface, these also indicate abrasive particles. To fix or prevent:
- Lube seal internally
- Remove abrasive materials from production environment
- Use gland surface finish recommended by manufacturer
Chemical degradation: When material becomes discolored, blisters or cracks prior to a seal failure, it’s likely due to chemicals degrading the material. The seal’s physical properties may also be seen to degrade. To fix or prevent:
- Ensure the seal’s material is compatible with chemicals in the environment
- Utilize an O-ring made from an elastomer that’s resistant to these chemicals.
Contamination: Foreign material on the seal’s surface cross-section indicates some type of contamination. This may result from conditions within the facility or degradation due to a chemical reaction. To fix or prevent:
- Use the correct seal material
Excess compression: Signs include a compressed seal occurring within a mated surface area, though alternatively, this could result from an improperly cured elastomer within the installed equipment or high temperatures. To fix or prevent:
- Confirm compatibility with material
- Ensure the correct design is being used
- Use only elastomers for O-rings that set at lower compression
Extrusion: When a seal’s edges become ragged or tattered along the low-pressure side, this is a warning of imminent failure. Though eroded gland edges, excessive clearances, high pressures, low modulus, too much elasticity, wrongly sized seal,s or other reasons could be the cause, it’s usually due to extrusion. To fix or prevent:
- Minimize clearances and pressure
- Use seals with elastomers that feature a greater modulus
- Use standby O-rings made from polymers
Heat degradation: When a seal shows radial cracks or its surface material becomes shiny and softens, the seal’s elastomers are likely not compatible with the system’s thermal requirements. To fix or prevent:
- Assess whether the seal’s surface can be cooled
- Select elastomer with sufficient thermal stability for seal
Improper installation: Damage occurring due to improperly installing a seal, or using the wrong type or size, can lead to seal failure. Indications like cuts, gashes or nicks on seal parts are indicative of this issue. To fix or prevent:
- Certify modulus is correct
- Clean surfaces and components of residual material
- Ensure the seal has the proper gland design
- Make sure the seal fits
- Remove any sharp edges
- Use the correct elastomer
Over-compression: When the surface of a seal develops circumferential splits with compressed surfaces, or if it becomes completely flattened, it’s likely to fail. Though this could result from improper design, environmental chemicals, changes in thermal volume or the selected seal doesn’t have properties necessary to withstand the compression, the problem is likelier due to over-compression. To fix or prevent:
- Confirm seal is sufficiently durable
- Ensure seal’s material properties are compatible with production environment
- Make certain seal meets any compression requirements
Now that we understand some common reasons why a seal might fail, let’s look at how to improve an O-ring seal.
How to Make an O-Ring Seal Better
O-rings are used in various industries, including aerospace, agriculture, plumbing, and transportation, to name but a few. These common ring-shaped seals fit into couplings, engines, pipes, pumps, shafts, and valves in various mechanical equipment. They’re used to prevent fuel, lubricants, oils, refrigerants, steam, water, and other liquids or gases from escaping. Understanding how to make an O-ring seal better starts with the installation process and, when done correctly, saves businesses time and money on maintenance and repair.
Here’s a practical checklist to improve O-ring performance across design, material, installation, and maintenance.
Material & Design Considerations
- Choose an elastomer compatible with the fluids, chemicals, temperatures, and pressures in your system.
- Ensure correct seal size: too large = poor sealing; too small = stress, risk of tearing.
- Design the gland (the groove in which the O-ring sits) for proper compression, to avoid over‐compression or extrusion.
- Select materials with adequate thermal stability and resistance to chemicals and environmental factors like UV, ozone.
Installation Best Practices
- Clean all mating surfaces; remove burrs, sharp edges and foreign particles.
- Lubricate the O-ring: use appropriate lubricant to reduce friction during installation and avoid damage.
- Avoid stretching the O-ring excessively; use installation tools or methods that minimize stress.
- When dealing with threads, apply tape or protection on threads and slide the O-ring rather than force it.
- Move seals into place rather than rolling or twisting them to avoid “spiraling” or uneven deformation.
Maintenance, Inspection & Environment
- Inspect seals periodically: look for signs of wear, abrasion, chemical damage, compression set.
- Keep environments clean: eliminate contamination sources such as dust, debris, and harsh particles.
- Monitor operating temperatures; avoid exposing seals to temperatures beyond their limits.
- Replace seals preemptively before they fail completely (based on inspection or known life expectancy).
Using Lubricant to Make O-rings Seal Better
To properly function, O-rings must be lubricated. Not only will lubrication help the seal last longer, but it will also prevent breakdowns of machinery, motors, engines, or other devices the seal is meant to protect should it fail. Applying oil or grease will protect the O-ring from damage when used. Lubricants also protect components by minimizing friction, providing water resistance, or preventing environmental degradation. Lubricating O-rings also reduces the chance of leaking seals in vacuum or pneumatic applications.
- Use suitable lubricants for the specific elastomer (synthetic greases, silicone or ester‐based options are often safer).
- Apply lightly and evenly; ensure lubricant doesn’t introduce contaminants.
- Avoid petroleum-based lubricants with rubbers if they cause swelling or degradation in that elastomer.
- Choose lubricants that remain stable under your temperature and environmental conditions.
Since most O-rings and seals are made from synthetic rubber-like material such as ethylene propylene diene monomer (EPDM) rubber, neoprene, or nitrile, they’re best lubricated with other synthetic compounds. Ester-based and silicone-based lubricants top this list. Their properties include reducing friction, low volatility, stability in high temperatures and fluidity in lower temperatures, and waterproofing. Both synthetic lubricants are safe, posing neither risk of contamination nor health, and are also usable with products containing natural rubber.
Frequently Asked Questions
1. How do I know if my O-ring material is appropriate for my application?
Test for compatibility with your fluids, exposure to chemicals, temperature extremes, and pressure. Review datasheets and, when in doubt, test small batches under your expected environmental conditions.
2. What lubricant should I use?
Choose a lubricant compatible with your elastomer. Ester- or silicone-based lubricants are often good safe choices. Avoid oils or greases that cause swelling or degradation in your specific rubber type.
3. Can improper installation alone cause seal failure?
Yes. Even if everything else is perfect (material, design, environment), installation mistakes like stretching, twisting, or nicking the seal can start damage that leads to failure.
4. When should an O-ring be replaced?
Replace seals when you observe signs of aging such as cracks, compression set (flattening), chemical wear, or loss of elasticity. Also schedule replacements as part of preventive maintenance before major failures.
5. Is over-compression worse than under-compression?
Both are problematic, but over-compression often leads to physical distortion and early failure; under-compression can result in leaks. Use the correct compression range for your specific O-ring design.
Talk to Our Experts About Better O-Ring Solutions
Improving an O-ring seal isn’t about major engineering overhauls—it’s about getting the details right. Correct material choice, thoughtful design, careful installation, and ongoing maintenance all combine to extend seal life, reduce leaks, and avoid costly failures.
By paying attention to what causes failures and following the best practices above, you’ll get more reliable, robust sealing in your systems. If you’d like help choosing the right elastomer or designing better O-ring glands, contact our team—we’re happy to assist.
