Experts in Silicone Gasket Solutions
Experts in Silicone Gasket Solutions



Silicone with additional fluorine groups for enhanced resistance to jet fuels, non-polar solvents, acids, and oils

Blue sponge and tan solid gaskets

Stockwell Elastomerics specializes in fluorosilicone rubber and offers solid sheets, sponge, electrically-conductive solids, molded parts, and die cut parts. In addition to supplying fluorosilicone materials and parts, Stockwell Elastomerics applies 3M and Adchem pressure-sensitive adhesive (PSA) backings to fluorosilicone rubber. Whether a silicone adhesive, an acrylic adhesive, or a double-coated combination adhesive is needed, Stockwell Elastomerics can assist in selecting the best adhesive for specific fluorosilicone applications.

What is Fluorosilicone?

Fluorosilicone rubber is based on silicone rubber but has fluorine groups added to the main polymer chain. Like silicone, fluorosilcone is a stable, long-lasting elastomer that resists compression set across temperature extremes. Unlike silicone, fluorosilicone contains trifluoropropyl groups that enhance its chemical resistance to non-polar solvents, fuels, oils, acids, and alkaline chemicals.

With their unique properties, flurosilicones are problem-solving materials for static sealing and cushioning in industrial, automotive, aviation, and aerospace applications. Visit the Fluorosilicone Data Sheets page for detailed technical information on the most popular available fluorosilicone materials.

SE207T Fluorosilicone Tiled Brochure

Request a Free Fluorosilicone Touch Brochure

Includes small samples of fluorosilicone materials to touch and feel.

Types of Fluorosilicone Rubber

Stockwell Elastomerics offers the following types of fluorosilicones.

The following sections describe these different types of fluorosilicone rubber.

SSP4773 High Performance Fluorosilicone

Stockwell Elastomerics supplies and converts SSP4733-XX, a family of high-performance, peroxide-catalyzed, heat-cured fluorosilcone rubber for demanding applications. These engineering compounds are certified and tested to MIL-DTL-25988, a U.S. military detail specification that covers fluorosilicone sheets, strips, molded parts, and extruded shapes.

Standard SSP4733-XX fluorosilicones are available in durometers ranging from 40 to 70 Shore A, where the XX after SSP4733 indicates the material’s durometer. Stock SSP4773 materials are calendared into rolls 12” wide and have thicknesses ranging from 0.020” to 0.125″. SSP4773 materials are also available in 12” x 12” molded sheets up to 0.5” thick.

Stock SSP4733 materials have short lead times and low minimum order quantities (MOQs). Custom compounds and constructions are also available. For example, SSP4773 is offered with fiberglass reinforcement, in custom colors, with laminates or coatings, or specialty test certifications. See the SSP4773-XX data sheet (PDF) for detailed material specifications.

Stockwell Elastomerics offers molded, die cut, water jet cut, and flash cut parts made of SSP4773 and other fluorosilicone rubber materials. Upon request, a variety of acrylic and silicone-based PSA backings can be laminated. To see the available adhesive choices, visit the Adhesives Data Sheets page.

Military and Aerospace Fluorosilicone

Square sponge window gasket and assortment of siliver aluminum solid fluorosilicones In addition to MIL-DTL-25988, standards and specifications for fluorosilicones include MIL-R-25988,  AMS-R-25988, and various numbered AMS standards. MIL-R-25988 is U.S. military specification. AMS stands for aerospace material specifications (AMS) that are established by the Society of Automotive Engineers (SAE), a global association of engineers and technical experts.

MIL-DTL-25988 supersedes MIL-R-25988 and divides fluorosilicones into Types, Classes, and Grades. Type 1 is for O-rings and Type 2 is for molded parts (other than compression seals) and for sheets, strips, and extruded shapes. Class 1 materials are for general-purpose use and divided into durometer-based grades. Class 2 materials are for high-strength, general-purpose use.

All four grades of the SSP4773 materials that Stockwell Elastomerics offers meet MIL-DTL-25988 Type 2 and Class 1 requirements. The 60 and 70 durometer grades meet both Type 1 and Type 2 requirements. SAE AMS-R-25988 is similar to MIL-R-25988 but is specifically for the aerospace industry. Stockwell Elastomerics also offers aerospace fluorosilicones that meet AMS 3325 through AMS 3331 standards.

Note: Some closed cell fluorosilicone sponge and fluorosilicone EMI gasket materials also meet military, aerospace, or other standards.

Fluorosilicone Sponge, Closed Cell

In addition to solid fluorosilicone rubber, Stockwell Elastomerics stocks Saint-Gobain NORSEAL® R10490 closed cell fluorosilicone sponge rubber. This material is made with a gum base, similar to solid fluorosilicone, but is expanded to introduce a closed cell structure. Compared to solid silicone rubber, NORSEAL R10490 seals with significantly lower closure force.

Because of the limitation of the expanding process, NORSEAL R10490 is produced to a maximum thickness of 0.125″; however, Stockwell Elastomerics offers bonded laminations up to 0.50″. These laminations are strong, and they exhibit similar chemical and temperature properties to the fluorosilicone rubber.

NORSEAL® R10490 Specifications

Saint-Gobain NORSEAL R10490 is capable of meeting these specifications:

  • AMS 3323, Class 2 medium density (tested in 2006)
  • MIL-R-6130 Type 2, Grades A, B and C (excluding paragraph 4.5.7 flame resistance)
  • ASTM D6576 Type 2 Grades A, B and C (excluding paragraph 15 flame resistance)

Saint-Gobain’s NORSEAL product line was formerly called COHRlastic®.

Fluorosilicone EMI Gasket Materials

Variety of circular, triangular, and window tan, silver aluminum filled fluorsilicone gaskets EMI gaskets require a fluorosilicone base for resistance to chemicals such as solvents and jet fuels. Stockwell Elastomerics offers electrically conductive fluorosilicones in cured sheets with thickness from .020″ to .125″ thicknesses, and custom molded gaskets. These sheets and gaskets can contain silver-plated aluminum particles or nickel-coated graphite particles. Both fill materials offer very good EMI attenuation.

Electrically Conductive Fluorosilicone Rubber for EMI Shielding

  • SNEF-50 – 50-durometer EMI fluorosilicone with nickel-plate graphite particles
  • SCF-444-P – 45-durometer EMI fluorosilicone with passivated silver-plated aluminum particles
  • SCF-447 – 70-durometer EMI fluorosilicone with silver-plated aluminum particle that meet MIL-DTL-83528, Type D

Commercial Grade Fluorosilicone

Stockwell Elastomerics also offers commercial grade fluorosilicone rubber for applications where specification grade fluorosilicones are not required, or cost sensitivity is a consideration. Commercial grade fluorosilicones do not have the testing and certifications that accompany materials such as SSP4773, but these solid elastomers have a lower price point. They are available in 36″ wide continuous rolls.

Blue solid molded fluorosilicone parts

Molded Fluorosilicone

Stockwell Elastomerics is an ITAR registered molder of fluorosilicone and EMI fluorosilicone components. Molded fluorosilicone parts are produced in compression molds and may be manually or cryogenically de-flashed. Compression molds are domestically manufactured, and custom fluorosilicone components are manufactured in Stockwell Elastomerics’ location in Philadelphia, Pennsylvania (USA).

Fluorosilicone, Flourosilicone, Florosilicone? Fluorosilicone Rubber? FVMQ?

Sometimes, the terms flourosilicone or florosilicone are mistakenly used to specify fluorosilicone products. Fluorosilicone is the correct term and spelling. Fluorinated silicone rubber is a more technical term for fluorosilicone. Fluorosilicone rubber is a common term for fluorosilicone, which is a synthetic material, not made from natural rubber. FVMQ (fluoro vinyl methyl siloxane) is the ASTM designation for fluorosilicone, but FS and FK are often used to designate fluorosilicones. Material suppliers also apply trade names to products.

Contact Stockwell Elastomerics for Fluorosilicone

Contact Us for further assistance with fluorosilicone / FVMQ / fluorosilicone rubber.

NORSEAL® and COHRlastic® are registered trademarks of Saint-Gobain.

Request a Free Fluorosilicone Touch Brochure

Includes small samples of fluorosilicone materials to touch and feel.