What’s So Special About Gasket Material for Exhaust?

Hot, Hot, HOT!! If you’re well versed in combustion engines, you likely associate exhaust systems with extreme heat. If you’re also well versed in gasket materials and how they perform in heat, you likely know that it takes a special material to withstand the conditions present in an exhaust system.

If you aren’t sure about what to look for in an exhaust gasket material, read on to learn how to identify a material that will survive in the exhaust environment.

 

Ideal Exhaust Gasket Material Characteristics

The harsh environments of exhaust systems can present a challenge if you don’t use acceptable gasket materials. Finding something to withstand the hot gases requires materials specifically designed to survive such conditions. What characteristics should you look for when selecting a gasket material?

1. Metal reinforcement: This provides strength and durability to maintain position in the face of the extreme conditions.

2. Heat tolerant facing material: Facing material must withstand heat of exhaust without disintegration over the life of the seal. Materials behave differently over time, be sure to choose what is best for you.

3. Abrasion resistance: This might be a factor in joints with high thermal motion, such as joints of dissimilar metals that expand and contract at different rates. In these cases, often a clad-style material is chosen. MTI offers the AR400 for situations such as this.

4. Low creep relaxation: Graphite products are a good example of a facing with low creep relaxation. This means it will not continue to lose thickness with the heat and time exposure, thus maintaining good flange loading to maintain the seal.

 

Making Your Decision

As we’ve said before, there is no one perfect gasket material out there for any application. There are a handful of materials that will meet the requirements of an application and it is up to you to decide which one performs best. In order to better educate yourself, you may need to talk to your trusted gasket material supplier and see what they say about a specific material and how it performs in applications similar to yours.

Until next time!

What's So Special About Gasket Material for Exhaust?

What Qualifies as ‘High Temperature’ When Talking About Gaskets?

If you ask half a dozen application engineers and gasket fabricators what they consider to be ‘high temperature’ in regards to their selection of a gasket material, you’re likely to get a range of answers. You’ll also find that none of them are really wrong, since ‘high temperature’ is a relative term. So, how does one navigate the world of high temperature gasket materials when the terminology is so ambiguous?

One way is to gain an understanding of the variety of materials that are on the market, so that you have a full appreciation of the strengths and weaknesses of certain materials as you move up in temperature. Also, it helps to at least have an idea of who the gasket material manufacturers are that manufacture materials that survive higher temperatures than what you currently work with. If you are ever faced with issues related to temperature, you need to know who you can go to for assistance.

 

What Is High Temperature?

In MTI’s world, ‘high temperature’ applications are generally anything that starts pushing into the 600°F – 800°F range and goes up from there (we have materials designed to survive temperature peaks of over 1900°F). The materials that we manufacture for the 300°F – 500°F range fall into a lower temperature classification in our catalog. However, some of you may only work with applications that reach 500°F, so that may be what you define as high temperature. Like we mentioned earlier, it is all relative.

So, maybe focusing on terminology isn’t the best way to find a solution for your issues. We decided to put together a chart for you to review. Below we have listed temperature ranges and typical materials that are known to work best in those ranges. Please note that this is not an exhaustive list, and we have not tested this information (however, we can speak for our materials). All materials must be validated for use in your specific application. This is meant as a general guide for you to use when you talk with your trusted gasket material supplier.

What Qualifies as 'High Temperature' When Talking About Gaskets?

 

Find Your Perfect Material

As you can see, temperature really does matter. The closer you creep towards 800°F, you must work with a different list of materials to survive in the applications. The good news is, what is out in the market does work. If you work with ‘high temperature’ applications, or believe that temperature is an issue in what you believed to be a ‘low temperature’ application, don’t hesitate to contact a gasket material supplier that specializes in materials that can survive the heat.

What is your definition of high temperature?

What Qualifies as 'High Temperature' When Talking About Gaskets?

Gasket Material Showdown: Vermiculite vs Graphite

Have you ever been doing research on a product and instead of being forced to read through a lot of mumbo-jumbo, you just want a nice eye chart with a little bit of explanation around it? Well, if you’re researching gasket materials and specifically want to see the differences between vermiculite and graphite, you’re in luck!

Each of these materials can hold its own, but they do have their specific strengths. Depending on your application, either vermiculite or graphite is going to be your best bet. Which one are you willing to put your money on?

What’s the Difference?

Vermiculite vs Graphite

In general, when you are working with exhaust applications with high temps and signs of oxidation, you will want to look at a vermiculite product because it will resist oxidation more than graphite. If you are working with exhaust applications where sealabilty is critical and temperatures are not extreme, the graphites are going to meet your needs. If temperatures prove to be too much for the graphite, a vermiculite-based product is your next step.

Find The Right Material

This breakdown should get you pointed in the right direction on your quest to find the best gasket material for your application. You don’t need to do it alone, though. If you still aren’t sure what you need, talk with your trusted gasket material supplier. They can give you the pros and cons of all of their materials and help you narrow down the choices in preparation for your testing.

A gasket material that works is your ace in the hole!

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6 Ways To Make Life Easier If You Work In High Temp Applications

Designing a gasket, selecting your gasket material and sealing your joint sounds like it should be a relatively straightforward thing to do. A lot of times, it can be. However, throw a high temp application into the equation, and things can become a bit more challenging. High temperatures have an effect on how certain materials behave, and you can’t treat these materials and applications the same as everything else.

Once you really understand how to deal with high temperature applications and what you need to know to start the process of selecting the right material for these applications, you’ve won half the battle.

High Temperatures? No Worries.

Here are a few tips and items of note that will get you moving in the right direction.

1. What should I pay attention to when adding heat?

Watch the temperatures at the flange, and what happens to gasket materials when they reach that level. Seeing what happens will help you to identify your needs going forward. If you are working with your gasket material supplier, they will definitely want to know what types of things you are seeing so they can make a recommendation for you.

2. Are there certain materials I should gravitate towards when dealing with high heat?

Some materials are designed for heat, they contain materials resistant to thermal degradation, such as graphites, vermiculites, micas, and other filler materials. Generally, high temp gasket materials should focus with this basis.

3. Are there certain materials I should stay away from?

Elastomers should be avoided with high heat. They will tend to get brittle and degrade quickly, leading to shrinkage and ultimately leakage.

4. What about oxidation?

Oxidation (thermal degradation) is the issue in high heat joints. Materials may not “burn” but they can degrade. Gasket materials must be chosen to withstand oxidation at operating temperatures. Graphites, for example, can have a wide range of oxidation resistance (or lack of) and should be chosen carefully. (Your gasket material supplier should have some choices for you. For example, MTI offers a variety of materials for exhaust materials with various levels of oxidation resistance.)

5. What about protection?

Protection is another issue. Using Armor-cladding is one way to protect the sealing layer, by sandwiching it between steel layers. This also provides scrubbing resistance which is also a factor in hot joints. Another form of protection is a flange ring, installed to create the primary seal and also protect the body of the gasket from the passing high temperature gases.

6. What about aging?

Aging is another issue relative to heat. At extreme temperatures, graphite for example, can age and oxidize. (MTI offers anti-oxidant graphite formulations to address this, providing up to 3X the service life of “regular” graphite in the same applications. It’s something to consider!)

Bring On The Heat!

Even though high temp applications require their own set of considerations, there are solutions that work. Be sure to talk with your trusted gasket material supplier if you have any questions about using the right material for your application. If you have a material that works “just ok”, we encourage you to see what else is out there. There are some great materials on the market that do very well in high temp applications.

What sealing issues do you see in your high temp applications?Request a Call