Why Material Selection Can Make or Break Your Seal

It’s easy to underestimate the importance of sealing material selection—until your seal fails, and you’re stuck with downtime and costly replacements. But it doesn’t have to be that way. Whether it’s avoiding pitfalls like choosing solely on price or understanding critical factors like chemical resistance, it’s possible to get it right on the first try. 

Common Pitfalls in Choosing Seal Materials

Selecting the wrong seal material can lead to frustrating, costly consequences, but it is a mistake made almost daily. Through our experience, we have identified a few common pitfalls people make when choosing their seal material. 

1. Choosing Based Solely on Price
   • Price is undoubtedly a factor when choosing a seal material. Unfortunately, it is often a little too high on the list of considerations. Opting for a cheap material might save money upfront but can quickly lead to an ineffective seal. As we know, ineffective seals quickly break down, and the “cheap” option can get really expensive really quickly.
   • Example: In a high-pressure chemical pump application, seals made from standard Viton quickly degraded due to exposure to aggressive chemicals. Replacing these with a combination of Markez® Z1352 perfluoroelastomer and PTFE significantly extended the seal life​.
2. Ignoring Environmental Factors:
   • One size seal definitely does not fit all. Many overlook or underestimate the impact of their operating environment’s unique challenges. These could include factors like drastic temperature swings, exposure to harsh chemicals, or even UV radiation. The result? A seal that’s out of its depth and breaking down under stress.
   • Ignoring environmental factors is like wearing flip-flops in a snowstorm—a mismatch bound to fail. Seals exposed to chemicals they can’t handle will swell, crack, or degrade. Extreme heat or cold can make even the best-looking seal brittle and ineffective.
   • Example: An aerospace company faced catastrophic seal failures in high-temperature laser equipment. The seals melted because they couldn’t handle exposure to laser energy or temperatures up to 600°F. By switching to Markez Z1407, a high-temperature, unfilled perfluoroelastomer, the seals survived and thrived under extreme conditions​​.
   • Taking the time to match seal materials with environmental challenges can save you from costly downtime, unexpected leaks, and a whole lot of headaches. Think of it as sealing success from the start.
3. Overlooking Long-Term Performance Needs:
   • O-rings and other sealing materials are often viewed as consumables. It is assumed they will be frequently replaced. While properly maintaining seals is important, you can maximize their lifespan to decrease downtime. Overlooking the long game when selecting a seal material is like putting a Band-Aid on a deep wound—it might work for now, but failure is just around the corner.
   • Dynamic applications, like moving pistons or rotating shafts, can quickly wear out seals that aren’t up to the task. External factors like rapid decompression or exposure to weather extremes can push seals past their breaking point.
   • Example: A seal for a high-pressure LCO2 cleaning chamber kept failing due to extrusion and the lack of a proper backup ring. Marco Rubber’s engineering team redesigned the seal with added mass in the most vulnerable area, creating a flange that blocked extrusion entirely. The result? A tenfold increase in seal life​.
   • Investing in materials designed to handle long-term performance needs—whether that means resisting abrasion, handling rapid pressure changes, or surviving UV exposure—ensures your seals stay effective longer, because no one wants to replace seals as often as their morning coffee.
4. Assuming “One Material Fits All”:
   • It’s tempting to stick with what you know. After all, if you know a material, it’s cheap and readily available, and you have a good supplier, it can feel like the easy answer. This is especially true when certain materials are touted as affordable and versatile. Unfortunately, this “one size fits all” approach can backfire—especially when seals are thrown into extreme environments.
   • Materials that work in one setting might completely crumble in another. For instance, seals that perform beautifully in a dry, static environment could crack under the strain of steam or ozone exposure. 
   • Example: In a high-temperature steam generator, metal seals were causing equipment damage and were too costly to replace frequently. By switching to a metal spring-energized PTFE seal with high-temperature capabilities, Marco Rubber helped the customer achieve reliable performance without hardware damage​.
   • The takeaway? Every application is unique, and so are its demands. Choosing the right material for the job means avoiding unnecessary downtime, expensive repairs, and the frustration of repeating the same mistakes. It’s all about sealing smarter.

Key Factors That Influence Material Selection

To avoid common pitfalls, we have a list of factors we always ask our customers to consider. If your seal is going to fail, it might have to do with improper sizing or installation. Otherwise, it will most likely have to do with one of the factors listed below. Thus, these considerations are a great place to start when choosing a seal material. 

1. Chemical Exposure:
   • Seals must stand up to the specific chemicals they’ll encounter. Incompatible materials can swell, crack, or degrade, leading to failure. For almost universal chemical resistance, perfluoroelastomers like Markez® Z1352 or Z1028 are a reliable choice​.
2. Ozone Exposure:
   • In outdoor or high-ozone environments, standard materials can crack or deteriorate over time. Ozone-resistant options, like EPDM, prevent these issues and ensure longevity.
3. Operating in High and Low Temperatures:
   • Seals need to stay tough in the heat and flexible in the cold:

• High Heat: FKM, FFKM, and PTFE materials excel in hot conditions.
• Freezing Cold: Silicone and specialty FKMs remain flexible even when temperatures fall.

1. High Pressure:
   • Seals must resist deformation and failure under high-pressure systems. High-durometer materials like FFKM and reinforced PTFE handle these extreme conditions without losing integrity​​.
2. Rapid Decompression:
   • Sudden changes in pressure can blister or crack seals. Materials like FFKM are specifically designed to handle these demanding applications​.
3. Static vs. Dynamic Applications:
   • Dynamic Applications: Moving parts demand flexible, wear-resistant, high-durometer materials to endure constant motion​​. Depending on the complexity of the application, we might recommend a different gland or seal design. 
4. Weather Exposure:
   • Outdoor seals face UV rays, rain, and temperature swings. Weather-resistant materials, such as specially formulated elastomers, can withstand these elements and extend seal life​​.
5. Steam or Hot Amines:
   • High-temperature steam or aggressive amines can break down standard materials quickly. Specialized options like high-temperature perfluoroelastomers are built to withstand these harsh environments​​.

Case Study: Extending Seal Life With the Right Material

The Problem

A chemical pump manufacturer consistently experienced seal failure. Their pumps faced extreme pressures of up to 5,000 psi, dynamic piston motion, and exposure to aggressive chemicals. Unfortunately, the standard Viton seals they were using couldn’t handle the challenge. Rapid degradation led to frequent downtime, high replacement costs, and frustration.

The Solution

Marco Rubber’s engineering team dove into the application’s requirements and came up with a solution tailor-made for the tough conditions. They selected a dual-seal system using:

• Markez® Z1352 (Perfluoroelastomer): This seal offered nearly universal chemical resistance, standing up to the harsh chemical environment.
• Filled PTFE Material: Acting as a secondary seal, the PTFE minimized wear during dynamic piston motion, ensuring long-term durability.

The Results

The dual-seal system passed rigorous testing with flying colors. The combination extended seal life significantly, slashing downtime and replacement costs. It was a game-changer for the manufacturer, proving that the right materials can transform a frustrating problem into a reliable solution.

Take the Guesswork Out of Material Selection

So, when you choose your seal material, are you checking off the right boxes? Your seal is the small, quiet cornerstone of preventing downtime. With the right material, you can ensure durability, reliability, and performance while avoiding the costly consequences of a mismatch.

Ready to get it right the first time?

We’ve got you covered. Explore our free Material Selection Guide to eliminate guesswork. This interactive guide lets you explore thousands of options. 

Have questions?

Our experts are here to help. Whether you need personalized recommendations or technical guidance, we’ll work with you to create a solution that works for your application. Contact us today.