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EMI Gaskets

SSP fabricates EMI gaskets from the EMI shielding silicones and fluorosilicones that we manufacture. This includes EMI gaskets in M83528 slash sizes. 

Whether your need standard or custom products, SSP offers low minimum order quantities (MOQs) and quick turn-around times.

Compare SSP’s EMI gaskets to Parker Chomerics CHO-SEAL and GORE EMI shielding. We are not a Parker Chomerics or a W.L. Gore distributor.

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What are EMI Gaskets?

EMI gaskets are fabricated parts that combine shielding against electromagnetic interference (EMI) with environmental sealing and insulation. They seal the gaps between mating surfaces and are made of elastomers that contain metal or metal-coated particles. 

Like other types of rubber gaskets, EMI shielding gaskets seal-out the external environment and seal-in to prevent leakage. What makes EMI gaskets different is that they also provide sealing against conducted or radiated EMI that can interfere with circuits. 

Normally, elastomers like silicone and fluorosilicone are electrically insulating; however, the addition of metal or metal-coated particles makes them electrically conductive instead. Consequently, EMI gaskets are sometimes called conductive seals or conductive gaskets.  

EMI Gasket Materials

EMI/RFI Shielding Elastomers

SSP supplies the following types of materials for EMI gaskets. Contact us if you need assistance with EMI gasket material selection.

Base Elastomers

SSP uses silicone or fluorosilcone as the base material.

  • Silicone provides broad temperature resistance and is a thermal insulator that can resist thermal cycling between temperature extremes.
  • Flurosilicone, a type of silicone with fluorine additions, is sometimes used as the base material instead. Fluorosilicone EMI gaskets cost more, but flurosilicone offers greater resistance to fuel, oil, and other chemicals.

Electrically Conductive Fillers 

The base elastomer is compounded with electrically conductive fillers. Silver prices and EMI gasket costs are often related, but they don’t have to be if your application supports a non-silver alternative.  

  • Nickel-aluminum
  • Nickel-graphite
  • Silver-aluminum
  • Silver-copper
  • Silver-nickel

Form Factors

SSP makes EMI shielding elastomers as:

How are EMI Gaskets Made?

SSP uses the following processes to fabricate EMI gaskets from the electrically conductive elastomers that we make. 

Cutting and Molding a Conductive Elastomer Gasket

SSP can flash cut or die cut EMI sheets, rolls, or extrusions. We also mold the compounds we make.

  • Flash cut EMI gaskets use CNC equipment to cut EMI elastomers into specific shapes without custom tooling. Flash cutting is ideal for rapid prototyping and short runs, and this gasket fabrication method produces extremely smooth edges with minimal loss of material. This digital manufacturing process works from your CAD file and supports flash cut EMI gaskets with a conductive PSA.
  • Die cut EMI gasket materials are cut into specific shapes and sizes from sheets or rolls of EMI elastomers. SSP makes its own dies in-house and fabricates die cut EMI gaskets with a high degree of uniformity, even across higher volumes. Precise dimensions, parts nesting, and punched holes with specific radii are readily achievable. SSP can apply conductive pressure-sensitive adhesive (PSA) tapes for peel-and-stick parts.
  • Molded EMI gaskets are produced using compression molding, a process that places a preformed rubber material into the cavity of a heated mold. SSP makes its own molds in-house and produces compression-molded EMI gaskets using the same materials that we supply as sheets, rolls, and extrusions. For large picture-frame style gaskets, molding can increase material yields and reduce material waste.

Bonding and Splicing a Conductive Elastomer Gasket

SSP can bond or splice the EMI extrusions that we flash cut or die cut.

  • Cold bonding joins EMI materials by using an RTV silicone adhesive or a non-silicone glue. Using a non-conductive adhesive increases the risk of EMI leakage, but conductive glues are available. With non-silicone glues, acrylic adhesives lack the temperature resistance of silicones.
  • Hot splicing joins EMI materials by applying heat and pressure. A splicing tool, or mold, is required, but hot spliced EMI gaskets have consistent properties throughout. They don’t have a “hard spot” like with a cold bonded EMI gasket either.

PSA Backings for Extruded EMI Gaskets

SSP can also supply EMI gaskets with a pressure-sensitive adhesives (PSA) backing for ease of insulation.

EMI Gaskets in M83528 Slash Sizes

SSP fabricates EMI gaskets in M83528 slash sizes from the MIL-DTL-83528 QPL Certified silicones that we make.  

Specification Sheet

Short Description

Long Description

M83528/001

Solid Cord (Circular Strip)

Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, EMI/RFI, Circular Strip, .040 Through .250 Diameter.

M83528/002

Standard EMI O-Rings

Gasketing Material, Conductive, Shielding Gasket, Electrical, O-Ring, Standard.

M83528/003

Solid D (Solid D Strip)

Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, EMI/RFI, Solid “D” Shaped Strip.

M83528/004

EMI Connector Gaskets (Flange Mount Connectors)

Gasketing Material, Conductive, Shielding Gasket, Electronic, EMI/RFI, Connector Flange Mount.

M83528/005

Non-Standard EMI O-Ring

Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, EMI/RFI, O-Ring, Non-Standard.

M83528/006

Rectangular D

Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, EMI/RFI, Rectangular, D-Cross Section.

M83528/007

Hollow D Strip

Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, EMI/RFI, Hollow D-Strip.

M83528/008

Hollow P Strip

Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, EMI/RFI, Hollow P-Strip.

M83528/009

Solid Rectangle Strip

Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, EMI/RFI, Solid Rectangular Strips.

M83528/010

Solid U Channel (Channel Strip)

Gasketing Material, Conductive, Elastomer, Electrical, EMI/RFI, Channel Strip.

M83528/011

Hollow Tube (Hollow O Strip)

Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, EMI/RFI, Hollow O-Strip.

M83528/012

Flat EMI Waveguide Gaskets (Flat Circular Washers)

Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, Electrical, EMI/RFI, Flat Circular Washer.

M83528/013

Round EMI Waveguide Gaskets

Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, Electrical, EMI/RFI, Waveguide.

M83528/014

Time Totalizing Meter

Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, EMI/RFI, for Use in Time Totalizing Meters Covered by MIL-M-7793.

Replacing CHO-SEAL EMI Gaskets

SSP makes EMI shielding elastomers that provide cost-effective alternatives to CHO-SEAL EMI shielding materials from Parker Chomerics. CHOMERICS® and CHO-SEAL® are registered trademarks of Parker Hannifin Corporation. SSP is not a Parker Chomerics CHO-SEAL distributor. 

Replacing GORE EMI Gaskets

SSP makes alternatives to discontinued UL 94 V0 flame-resistant EMI shielding materials from Gore. Gore® is a registered trademark of W.L. Gore & Associates, Inc. SSP is not a Gore distributor.

EMI Shielding Gaskets: Compression

Like other types of elastomeric gaskets, an EMI shielding gasket is compressed by a percentage of its size. This compression forms a seal that physically fills the gap between two surfaces. When the compressive stresses are removed, the EMI gasket is supposed to return to its original thickness. If it does not, this irrevocable deformation (compression set) can leave a gap and cause seal failure.

Harder materials with higher durometers are more difficult to compress, but electrically conductive silicones are not excessively hard because of the addition of particles. In fact, EMI silicones are available in a range of hardnesses, including lower durometers for gaskets where there is less closure force.

EMI Shield with Enclosure Sealing and Insulation

EMI gaskets that are made of electrically conductive silicones are installed within enclosures. Examples include electrical and telecommunications equipment, electronic and medical devices, robotic end-effectors, and flat-panel displays.

Some EMI enclosure shielding needs to meet specific requirements for ingress protection (IP) against dust and water.

  • North America: EMI gaskets are sometimes used within NEMA enclosures that need meet specific IP requirements from the National Electrical Manufacturers Association.
  • Europe: IP ratings or codes are defined in IEC 60520. As with NEMA enclosures, some IP enclosures require EMI gaskets for protection against electromagnetic interference.

EMI Shielding Gaskets: Standards

EMI gasket standards include requirements for EMI shielding and environmental sealing. Some standards, such as NEMA and IP ratings, apply only to environmental sealing but may still affect EMI gaskets made of electrically conductive silicones. In addition to NEMA, the following organizations maintain standards that EMI gasket designers may need to meet.

  • U.S. Department of Defense (DoD)
  • Underwriters Laboratories (UL)
  • ASTM International (ASTM)

EMI Military Standards

For some military applications, EMI gaskets must use materials that meet MIL-DTL-83528 requirements. MIL-DTL-85528 is a detail specification from the DoD that establishes general requirements for electrically-conductive elastomeric shielding gaskets. MIL-DTL-83528 contains lettered sections, each of which contains requirements for the base elastomer, durometer, fill material, plane wave shielding effectiveness, and continuous use temperature. Because MIL-DTL-83528 only applies to fill materials that are pure silver or silver-coated, it does not encompass nickel-graphite filled silicones or wire-oriented silicones that contain Monel or aluminum mesh.

UL Standards

UL maintains two flammability standards that may apply to EMI gaskets: UL 94 V0 and UL 50-E. Neither standard is silicone-specific, and both apply to plastics. UL 94 V-0 is part of a larger standard, UL 94, that classifies materials according to how they burn in various orientations and part thicknesses. UL 50E is an IP standard against dust and water that applies to enclosures for electrical equipment that will be installed and used in non-hazardous locations.

ASTM Standards

For EMI gaskets that require resistance to galvanic corrosion, such as those used in marine environments, ASTM B117 may apply. Galvanic corrosion occurs when two dissimilar metals are immersed in a conductive solution, such as salt water, and are electrically connected. There are also electrically conductive silicones for EMI gaskets that need to meet ASTM E595 for outgassing, a problem in high vacuum environments, such as outer space, where released gases can condense upon and cloud optics. 

EMI Gasket Applications

Telecommunications Equipment

  • Examples: Base stations, routers, antennas.
  • Purpose: Prevent interference between components in high-frequency communication systems and ensure compliance with EMI regulations.

Aerospace and Defense

  • Examples: Avionics, radar systems, communication devices.
  • Purpose: Protect sensitive equipment from external EMI and ensure secure operation in environments with high electromagnetic exposure, such as military vehicles and aircraft.
  • Additional Information: Die Cut EMI Gasket Materials for Avionics and Defense

Automotive Electronics

  • Examples: Electric vehicle (EV) battery enclosures, infotainment systems, sensors.
  • Purpose: Shield sensitive automotive systems from EMI caused by internal components (e.g., electric motors, inverters) or external sources (e.g., nearby power lines).

Medical Devices

  • Examples: MRI machines, diagnostic equipment, wearable medical devices.
  • Purpose: Ensure precision and reliability of sensitive medical electronics in environments with strict EMI control requirements.

Consumer Electronics

  • Examples: Smartphones, tablets, laptops, gaming consoles.
  • Purpose: Minimize interference in densely packed electronic systems and ensure proper functionality in wireless communication.

Industrial Equipment

  • Examples: Robotics, motor controllers, programmable logic controllers (PLCs).
  • Purpose: Protect control systems and equipment from electrical noise in industrial settings with heavy electromagnetic activity.

Military Enclosures

  • Examples: Communication shelters, command centers, electronic warfare systems.
  • Purpose: Provide both EMI shielding and ruggedized protection against environmental factors like dust, water, and vibration.

Satellite Systems

  • Examples: Communication satellites, scientific instruments.
  • Purpose: Protect sensitive electronics from cosmic radiation and electromagnetic noise.

Power Electronics

  • Examples: Power supply units, transformers, inverters.
  • Purpose: Reduce EMI in high-power systems to ensure compliance with regulations and proper device performance.

Data Centers

  • Examples: Server racks, network switches.
  • Purpose: Protect systems in environments with high-density electronic equipment and potential for cross-talk interference.

EMI Gasket Q&A

Is an EMI gasket always an EMI silicone gasket?

No. EMI gaskets can be made of other elastomers, typically EPDM and flurosilicone. The base elastomer imparts properties such as water, weather, temperature, and chemical resistance.

Engineers choose an EMI fluorosilicone when the application requires a combination of EMI shielding, environmental sealing, and protection against chemicals such as fuels, solvents, and de-icing fluids. It’s this enhanced chemical protection that makes an EMI fluorosilicone a better choice than an EMI silicone for some applications. Examples include sealing the fuel doors on vehicles or on aircraft exteriors. SSP supplied both EMI fluorosilicone and EMI silicone products as ready-to-fabricate materials or ready-to-install solutions.     

Yes, there are other types of EMI products than EMI gaskets. Examples include conductive plastics, EMI paints, EMI adhesives, and metal gaskets such as berylium fingerstock. SSP does not supply these other materials, but your application may require them.

EMI shielding or EMI gasketing isn’t the only way to promote electromagnetic compatibility and to address compliance with EMC regulations and standards. Electronic designers can also use EMI suppression filters, which target a specific source of noise and control the flow of electromagnetic energy. Typically, EMI filters are used at the inputs and outputs of an electrical system since these are vulnerable points where gaps in EMI shielding may occur. EMI filters are also used at other specific circuit locations for targeted protection. In many if not most electronic designs, both EMI shielding and EMI filtering is used.

EMI gasketing is really just another name for EMI gaskets or EMI shielding gaskets. “EMI gasketing” can refer to a finished product, but it may also be used to describe a ready-to-fabricate material.

Not necessarily. Depending on what’s added to the base elastomer, a material such as silicone can be electrically conductive or thermally conductive. The products that SSP makes are electrically conductive because we add metal, bimetallic, or metal-coated particles to the elastomer. We do not supply thermally conductive elastomers. 

Seals can be made of elastomers that are electrically conductive, thermally conductive or both. SSP makes conductive seals that are electrically conductive and that provide both environmental sealing and EMI/RFI shielding. 

EMI seals are EMI gaskets. The term is also used instead of shielding gaskets or EMI gaskets. Conductive seals that conduct electricity (as opposed to heat) can also provided shielding against electromagnet interference. 

EMI sheets are made in various sizes and cut into EMI gaskets. Several different cutting processes can be used. For low volumes, flash cutting or water jet cutting is a cost-effective choice. For higher volumes, die cutting is typically used. SSP provides flash cut EMI and die cut EMI gaskets, but we also offer molded EMI seals as well.

Yes. If you need an EMI gasket for rapid prototyping, SSP can use flash cutting or bonding (instead of die cutting or molding).

An EMI extrusion can be converted into a EMI seal or EMI gasket that mounts over a flange or fits within a groove. As an extrusion, the product has a fixed cross-sectional shape such as the letter “D”. Cords or cordstock are a type of EMI gasket extrusion. SSP supplies EMI gasket extrusions and can cut and bond them into EMI O-rings. 

An EMC gasket is designed to help electrical equipment and systems to function acceptably in their electromagnetic environment. The promote electromagnetic compatibility (EMC), the ability to function in the presence of of other electrical and electronic equipment. All such equipment emits electrical energy, and some of that emitted energy may interact and interfere with other equipment. Alternatively, equipment may be susceptible to receiving energy emitted from other sources. 

Yes. Please contact SSP to discuss your application.

Additional EMI Gasket Resources