The Why’s and How’s of Coating Your Gaskets

There are many reasons why one might coat a gasket. The motive may vary, but one thing is certain – a quality coating is necessary. Today, we’re going to look at some of the reasons why you may want to coat your gaskets as well as the types of coatings you should be seeking out and how they may be applied.

Continue reading for some of the why’s and how’s of coating gaskets.


Why Coat?

Whether your decision to coat your gaskets is driven by performance or cosmetic needs, there is a coating to meet your requirements. Here are a few reasons why you may choose to coat your gaskets.

1. You want to stand out – Sometimes it is strictly cosmetic. You want your gaskets to be red, so you coat them, and everyone knows red gaskets belong to you. Users receive the benefits of the coating, but your main goal is branding.

2. You need to provide some ‘slip’ in your joint – Do you have a lot of movement between your flanges? Movement can be caused by expansion and contraction of the metals and sometimes those happen at different rates. Having an anti-stick coating on your gaskets protects them from damage and allows them to move with the flanges.

3. You intend to try to reuse your gaskets – Although it usually isn’t recommended by those in the gasket industry, there are some users that try and successfully reuse gaskets. Coated gaskets tend to not see as much wear and tear during use, and typically can be removed without much damage.

4. You need an easier teardown – Sometimes speed and efficiency is a necessity during teardown, or you have better things to do than spend hours bent over a flange chipping away at a gasket. Regardless, coatings provide anti-stick properties that allow for a clean release from the flanges.

5. Seal improvement – Coatings can also provide “micro-sealability”. In the case of fiber-based products, coatings can saturate the fibers and block potential leak paths through the body of the gasket.


How to Coat?

The first thing to understand is the difference between your choices in coatings. Some coatings contain a release agent for anti-stick properties, while others contain polymer compounds for enhanced sealing.

To apply the coatings, it ultimately depends on the form in which the coating is produced. However, typical means of application are spraying, rolling, dipping or brushing. Depending on your preferences, it can be added to materials prior to being cut or applied to finished parts.  Coating a cut part is preferred, as the coating will then be applied to the inner and outer sealing edges for full encapsulation.


Know Your Need, Make Your Selection

Once you have decided that a coating is necessary for your gaskets, you just need to find the one that best fits your need. Most gasket material suppliers are familiar with coatings, so if you have any questions, talk to one you trust to get the answers you are looking for.

Should YOU be coating YOUR gaskets?

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3 Reasons Why You May Want to Utilize an Insulating Gasket

Sometimes a gasket needs to be more than just a gasket. There are times you may find that you are in need of an insulating gasket. There are also times that you could use an insulating gasket and don’t even realize it. If you’re not quite sure what you need, continue reading to learn about a few instances when an insulating gasket may be a benefit to your application.

Before we jump into a few examples, we thought we’d start with a short explanation on insulating gaskets in general. First, it isn’t a new gasket technology. Gaskets with insulative properties have been on the market for years. However, due to the increased heat in applications, the benefits of these materials are now in demand as engineers are constantly working to manage the heat.

So what are these materials? Metal reinforced composite laminates are your best choice when it comes to high temperature gaskets that also require insulative properties. Insulative materials by themselves can be fragile, the metal core gives them strength.


Reasons to Utilize an Insulating Gasket

1. There isn’t room for a heat shield – Engines are getting both hotter and smaller, which is not a good combination if there are sensitive components that need protection. Designing a heat shield small enough to fit into some of these areas can be a difficult task. If there is a way to utilize the insulating properties of your gasket to reduce the heat flow, you may have solved your space issue.

2. Save money and simplify your design – We don’t know any engineers that want to add cost and complexity to any design, so if there is a way to minimize both of these with simply a gasket, why wouldn’t you at least check it out?

3. You suspect heat soak is present – All systems may be humming along while the application is running. However, what happens when it is turned off? Heat soak is a common issue when there are no cooling systems protecting sensitive components. An insulative gasket does its job whether or not the application is running. An example of this might be EGR valves, where actuators are better if they don’t get as hot as the valve itself. Heat soak can be an enemy here.


Selecting a Material

As with any application, you need to ensure that any gasket material chosen is suitable for the conditions that it will see. The best insulative materials are going to be metal reinforced composites that contain vermiculite, mica or fiber materials. Finding which one seals and insulates best in your application is something that will need to be tested. As you explore this idea, talk to your trusted gasket material supplier to narrow down your choices.

Have you used an insulating gasket before?

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What is the Benefit of a Gasket with a Screen Core?

Metal-reinforced gaskets are a staple in the industry. They provide radial strength for both handling and in-application uses. The gaskets are dimensionally stable and very robust.

But some gaskets have screen cores…is this a good thing? In most cases, no. Read on to learn why.


Screen Core Materials

Screen core is one version of a metal center layer sandwiched between two layers of sealing material. It provides a metal core layer for a laminate that offers strength while allowing a place for an adhesive bond to occur. It also provides an additional level of lateral strength as the facing cannot slide laterally on the screen core. While it seems like it might be a good idea, the drawback comes with the issue of sealability. By its nature, screen is a woven material, generally wire, in an over/under overlapping pattern. This is what creates the problem. The over/under configuration provides a leak path for the fluid being sealed. The facing material must conform tightly to the metal or a leak will generate. This is difficult for the facing to do as there is an inherent void to be dealt with. In some cases, this can be addressed by a heavy layer of adhesive, but this is not the best solution since it only puts a band-aid on the problem.


If Not Screen Core, Then What?

A better solution is a solid core laminate using flat metal and a thermally-cured adhesive. This product provides NO leakpath along the core due to the adhesive bond. Another core style is expanded steel. While it is a “porous” core, it also has NO direct leak path through the core by the nature of its design, thus allowing the adhesive to bond the two sides of facing directly through the core.

As with all products that contain a thermally-cured adhesive, you need to pay attention to the operating temperatures of your application and the specification of your chosen material. In fluid sealing applications, temperature capability of solid core materials is often more than sufficient to withstand the conditions of the application.


Find A Solution

As you can see, there are some things to be aware of if you’re thinking about using a screen core as a layer of metal-reinforcement. For fluid sealing applications, there are better choices available, such as solid core laminates or expanded core laminates.

If you aren’t familiar with solid core laminates, talk with your trusted gasket material supplier to learn about your options.

What type of material do you prefer in this situation?

Metal Tech offers solid core products under the SURBOND product group for fluid sealing applications.

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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!

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3 Reasons You Know That it is Time to Replace Your Head Gasket

Sometimes bad things can happen to good engines. This can be the case with a head gasket failure. Depending on the design requirements and the suitability of your gasket material for the application, the useful service life will vary. However, any application that is in use long enough may require a replacement of the head gasket.

Head gaskets are one of the more difficult repairs on an engine. They require substantial removal of parts, careful cleaning and preparation of surfaces, and methodical replacement and reassembly of the engine components. Nobody really WANTS to replace a head gasket, but sometimes, it’s just necessary.

How do you know when this is needed? Here are a few warning signs:


It’s time to replace your head gasket when there is…

1. Loss of compression: Failure of the combustion seal results in a loss of compression in the engine and loss of power. This is normally obvious when it occurs and requires a replacement of the head gasket right away.

2. Coolant in the oil (internal loss of fluid): If the body of the gasket loses load and leaks coolant into the oil ports, bad things happen. The oil will be compromised in its lubricity, resulting in possible damage to the internal engine parts. It may also result in excessive heat and other failures. This requires replacement of the head gasket immediately.

3. Leakage down the block (exterior loss of fluid): The body can also fail to seal the fluid ports resulting in external leakage of the fluid (either oil or coolant) down the side of the block. This can be a more gradual failure of the head gasket and often not noticed until much later.


Replacing a Head Gasket

If you have arrived at the decision that a head gasket needs to be replaced, you need to be aware of a few things.

1. Know that you may not be able to replace it with a similar gasket material without significant repair cost also put into the flanges. Why? If the original gasket was a MLS (multi-layer steel) construction, this will require extremely smooth surface finish preparation (which equals repair costs). There are other gasket material technologies out there that will save you from this cost.

2. There are various types of replacement head gaskets available. Graphite products are an excellent choice and can be made to the required thickness and density to meet your needs.

3. It is a complicated repair and replace operation, but not impossible. Once completed, the engine will have a new lease on life for many more happy miles.

If you have any questions about what you’re seeing with your gasket material, or are looking for suggestions on the types of gasket materials that will work best when a head gasket is being replaced, talk to your trusted gasket material supplier. They will be able to get you going in the right direction.

Is there anything you would add to the warning signs list?

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