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?Surbond product comparison

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

4 Questions to Ask When You Need to Seal Fluids

Whether you are new to the fluid sealing market or you’ve been immersed in it for years, there are some considerations that must be made when you need to seal fluids. Some may be made subconsciously, but others sometimes require much debate and testing. This week, we thought we’d lay out the important questions that need to be asked (and why) when you are faced with a joint that requires fluid to be sealed.

The List

1. What fluid are you sealing?

Is it Coolant? Oil? Fuel? Water? Other? This can affect your material choice.

2. At what temperature will it be operating?

It is best to identify operating usage extremes, to understand how the gasket and the fluid will age or withstand exposure to elevated temperatures for extended periods of time.

3. How aggressive is the fluid? Is it compatible with my gasket?

Some gaskets are designed to “swell” when in contact with fuels and oils. This “controlled swell” actually creates a better seal on the inside contact edge of the gasket. Of course compatibility must also be considered so the gasket does not disintegrate. A good example of what not to do is using a low cost exhaust material in an oil-sealing application. The material will be weakened by the absorbed fluid.

4. What sealability level do I need?

Sometimes in engine applications, additional features are added for various purposes. A silicone coating for “cold sealing” an engine is one example. This provides additional sealability while the engine is still warming to its operating conditions.

Seal It

Sealing fluids can be a tricky project. When the goal is to find a material that will meet or exceed the design service life, you need a material that is right for your application. Your gasket material supplier is your best resource to talk through your material requirements. Whether you are in the planning stage, troubleshooting your current material, or on the hunt for a replacement material, a good supplier of gasket material is going to be with you every step of the way. Nobody knows our material better than we do!

What issues have you had with sealing fluids in your applications?

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