Custom Gaskets

Viton™ Gaskets, FKM Gaskets

Custom Viton™ gaskets / fluoroelastomer (FKM) gaskets for demanding applications

Long, black chemically resistant Viton gaskets with waterjet cut holes along the length

Stockwell Elastomerics manufactures custom Viton™ gaskets and fluoroelastomer (FKM) gaskets using high performance fluoroelastomer gasket materials. These gaskets are utilized for demanding applications with exposure to high heat and aggressive chemicals, including aerospace, analytical instrumentation, chemical processing, and other many other critical industries. Using manufacturing processes such as molding, die cutting, and waterjet cutting, Stockwell Elastomerics fabricates custom Viton™ gaskets / FKM gaskets at its manufacturing facility in Philadelphia, Pennsylvania.

What is Fluoroelastomer Gasket Material?

A detailed explanation of fluoroelastomers in general, and Viton™ made by Chemours™ in particular, is provided on the FKM materials page.

How are Viton™ Gaskets Made?

Stockwell Elastomerics fabricates Viton™ gaskets / FKM gaskets using these processes:

Compression molding produces Viton™ gaskets from ready-to-mold compounds. Tooling is required, but gaskets are molded as a single piece. For parts that have an empty area in the middle, compression molding can maximize material yields since there is no unused center to discard.
Waterjet cutting is a tool-less process. Like flash cutting, it uses a gantry-style table and converts sheets, rolls, or extrusions to specific shapes and sizes. However, waterjet cutting uses a highly pressurized stream of water instead of reciprocating knives.
Die cutting requires metal tools called dies. This adds costs and time to projects, but die cutting is cost-effective for high-volume production. Like waterjet cutting, die cutting supports parts nesting to layout cutting patterns that minimize material waste.

Advantages of Viton™ Gaskets

Viton™ gaskets specifically, and FKM gaskets in general, are able to resist a wide range of aggressive chemicals, including:

Oils, fuels, and petroleum-based fluids
Hydraulic fluids and lubricants
Acids, alkalis, and organic solvents

This makes Viton™ especially effective in environments where other elastomers, such as nitrile or EPDM, would degrade. In addition to high temperature resistance, Viton™ gaskets have low gas permeability, which makes them a good choice for fuel systems and vacuum applications. Viton™ performs well with a broad range of fluids, including biodiesel and oxygenated fuels.

Among their advantages, fluoroelastomer gaskets have exceptional tensile strength (upwards of 2000psi) and are tear and abrasion resistant. Viton™ is also inherently flame-resistant and self-extinguishing once the heat source is removed. Specific grades or types include general-purpose (Viton™ A), enhanced chemical resistance (Viton™ F), and specialty grades that are FDA-compliant or designed for extreme high performance.

Disadvantages of Viton™ Gaskets

Viton™ is more expensive than common organic elastomers such as nitrile or EPDM. Most Viton™ grades stiffen at temperatures below 30°F (-15°C) resulting in a loss of flexibility and sealing capabilities. For cold environments like this, gaskets made of silicones or fluorosilicones may be a better choice.

Among their disadvantages, Viton™ gaskets are relatively dense, which can limit their utility in lightweight applications. Compared to other elastomers, including natural rubber and nitrile, Viton™ also has less elasticity. This makes it less than ideal for sealing and cushioning applications that require high stretch or recovery.

Viton™ gaskets resist most chemicals, but they’re less effective against the following substances:

Ketones and amines
Hot water and steam over prolonged periods
Organic acids in high concentrations

FFKM (see below) may be a better choice for these applications, and certain grades of Viton™ may degrade more quickly in high radiation environments such as nuclear applications.

Viton™ Gaskets vs. FKM Gaskets and FFKM Gaskets

All Viton™ gaskets are FKM (fluoroelastomer) gaskets, but not all FKM gaskets are made of Viton™. Although Viton™ is one of the most widely used types of FKM, manufacturers such as 3M™, Solvay™, and Daikin™ have their own FKM products. Viton™ is produced under the strict manufacturing standards of Chemours™ and is generally more expensive than other FKM materials because of its branding, quality assurance, and multiple grades.

Viton™ is not a perfluoroelastomer (also called FFKM), but FFKM gasket materials may be required for applications in the semiconductor and pharmaceutical industries. That’s because FFKM gasket materials such as Kalrez® (a DuPont™ product) have low outgassing and high purity properties. FFKM is more expensive, however, and this can make Viton™ a better choice for applications that don’t require the extreme performance of FFKM.

Another gasket material to consider is AFLAS®, a distinct type of fluoroelastomer, a tetrafluoroethylene-propylene (FEPM) copolymer, made from tetrafluoroethylene and propylene (TFE/P), developed by AGC Chemicals.

Grades of Fluoroelastomers for Gaskets

Fluoroelastomers, like other polymers, are available in different grades with specific benefits for different sealing applications. Contact Stockwell Elastomerics’ Applications Engineers for gasket material selection assistance.

Contact Stockwell Elastomerics for Viton™ Gaskets / Fluoroelastomer Gaskets

Contact us for Viton™ gaskets and FKM gaskets for assistance with design considerations ranging from material selection to tooling.

Viton™ is a registered trademark of The Chemours Company FC, LLC.
Chemours™ is a registered trademark of The Chemours Company FC, LLC.
Kalrez® is a registered trademark of DuPont de Nemours, Inc.
DuPont™ is a registered trademark of DuPont de Nemours, Inc.
3M™ is a registered trademark of 3M Company.
Solvay™ is a registered trademark of Solvay SA.
Daikin™ is a registered trademark of Daikin Industries, Ltd.
AFLAS® is a registered trademark of AGC Chemicals.