Four Applications for Felt Gaskets

Industrial felt is a nonwoven textile made from wool, polyester, or a combination of the two. If you think felt is just a crafting material, think again. Industrial felt is produced to rigorous specifications and felt gaskets are found in a wide range of applications.

Basics of Felt Gasket Material

Industrial felt is made by entangling wool and other fibers. It’s sold in roll form and in a range of thicknesses and densities. It can be supplied with a PSA to simplify installation.

SAE standards assign F numbers to felt, which makes it practical to specify the type needed. Those most often used for gaskets are F-3, F-51 and F-55 although other grades are available.

Felt resists tearing and abrasion and polishing rather than wearing metal surfaces it rubs against. It’s compressible with good elastic recovery, and when made from wool it’s considered a “green”/sustainable material. Perhaps the most interesting thing about felt though is its open structure. This lets it hold and filter fluids, which leads to a host of applications.

Four Felt Gasket Applications

The main uses are:

  • Sealing

Felt gaskets are used as bearing seals and as wipers in motion systems. The fibrous structure stops dust from reaching the bearing surface and can also retain oil or grease for lubrication.

  • Lubrication

Felt is comparable to foam in how it can hold oil but has the advantage of “wicking” behavior. This refers to how it can “suck up” oil, which makes it an effective way of lubricating shafts and guideways.

  • Filtration

Felt is an excellent material for removing particulates from liquids and gases. It works down to micron level and can be oil-impregnated for even higher performance.

  • Noise and vibration attenuation

Felt gaskets are used in architectural and automotive applications to reduce the transmission of noise and vibration. This results from individual fibers absorbing energy by rubbing together rather than transmitting it.

Discuss Your Application With Us

If sealing, lubrication and filtration are of interest, talk to us. Our specialists can review your application and recommend a felt to improve performance, reliability and life. Contact us today!

When to Use Felt Gasket Material

Most gasket materials are elastomeric or rubber-like in nature, but there’s another material that’s surprisingly effective in some sealing applications: wool. When compressed to a uniform density wool becomes felt. Felt has been used for sealing and gasketing for a long time and still has its uses.  Felt seals suppliers offer a variety of options.

A “Non-Woven” Material

Most felt is produced by compressing wool into rolls of material. Wool fibers have a kind of “fish scale” surface that lets them hook together randomly. This creates a material that’s soft and compliant with a high level of resiliency. It can absorb and hold liquids even better than an open cell foam while resisting attack by oils and temperatures up to 200°F. An added benefit is that felt won’t unravel or fray like woven fabrics.

Industrial wool felt is specified by an SAE standard. This assigns grades from F-1 to F-55. Higher numbers indicate lower density, and these grades have less ability to absorb vibration and resist abrasion.

Felt is produced from other materials, most notably polyester fiber. Polyester felt will withstand temperatures up to 300°F but its properties and behavior are not addressed by the SAE standard.

Uses of Felt Gasket Material

  • Noise-deadening

Thanks to strong resilience, felt gasket material can absorb movement between surfaces that would otherwise cause rattles and squeaks. By preventing the transmission of vibration it’s also a good sound-deadening material.

  • Filtration

The random orientation of fibers in felt make it a very effective filtration medium. Filtration is further enhanced by soaking in oil. Wool fibers hold oil on their surface, which traps very small particles being drawn through.

This ability to retain oil also makes felt a good seal against moving surfaces such as shafts. The wool adapts to changes in gap while oil provides lubrication and simultaneously prevents fluid transmission.

Compliant but Durable

As a soft gasket material, felt is similar to an open cell neoprene, EPDM or silicone foam. Its upper-temperature limit is lower, but depending on grade, abrasion resistance can be higher. If you’re looking for a material that can lubricate as well as seal, ask about felt.