EMI gaskets from Specialty Silicone Products (SSP) combine shielding against electromagnetic interference (EMI) with environmental sealing and thermal and electrical insulation.
SSP fabricates EMI gaskets from the shielding silicones and fluorosilicones we make right here in the USA.
Ask SSP for a standard or custom EMI shielding gaskets, including MIL-DTL-83528 compliant gaskets. SSP offers low minimum order quantities (MOQs) and quick turn-around times.
In addition to conductive elastomer gaskets, SSP makes conductive O-rings that provide environmental sealing and electromagnetic interference protection. We also supply EMI shielding materials as sheets, rolls, extrusions, and moldable compounds.
SSP fabricates EMI gaskets from the MIL-DTL-83528 QPL Certified silicones that we make. MIL-G-83528/MIL-DTL-83528 spec is a U.S. military detail specification that contains requirements for electrically-conductive silicone and electrically-conductive fluorosilicone gaskets for shielding against electromagnetic interference (EMI) and radio frequency interference (RFI). The table below describes M83528 slash sizes.
Specification Sheet | Short Description | Long Description |
M83528/001 | Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, EMI/RFI, Circular Strip, .040 Through .250 Diameter. | |
M83528/002 | Gasketing Material, Conductive, Shielding Gasket, Electrical, O-Ring, Standard. | |
M83528/003 | Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, EMI/RFI, Solid “D” Shaped Strip. | |
M83528/004 | Gasketing Material, Conductive, Shielding Gasket, Electronic, EMI/RFI, Connector Flange Mount. | |
M83528/005 | Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, EMI/RFI, O-Ring, Non-Standard. | |
M83528/006 | Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, EMI/RFI, Rectangular, D-Cross Section. | |
M83528/007 | Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, EMI/RFI, Hollow D-Strip. | |
M83528/008 | Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, EMI/RFI, Hollow P-Strip. | |
M83528/009 | Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, EMI/RFI, Solid Rectangular Strips. | |
M83528/010 | Gasketing Material, Conductive, Elastomer, Electrical, EMI/RFI, Channel Strip. | |
M83528/011 | Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, EMI/RFI, Hollow O-Strip. | |
M83528/012 | Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, Electrical, EMI/RFI, Flat Circular Washer. | |
M83528/013 | 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. |
SSP’s MIL-DTL-83528 QPL certified EMI gasket materials are shown below. This standard is divided into lettered sections and sometimes written as MIL-G-83528 or M83528. Choose products that meet MIL-G-83528 Type A, B, C, D, or K requirements.
Silver-plated, copper-filled silicone capable of 110 dB of plane wave shielding effectiveness at 10 GHz with a continuous use temperature range of -55°C to +125°C. | |
Silver-plated, aluminum-filled silicone capable of 100 dB of plane wave shielding effectiveness at 10 GHz with a continuous use temperature range of -55°C to +160°C. | |
Silver-plated, copper-filled fluorosilicone capable of 110 dB of plane wave shielding effectiveness at 10 GHz with a continuous use temperature range of -55°C to +125°C and resistant to solvents and jet fuels. | |
Silver-plated, aluminum-filled fluorosilicone capable of 90 dB of plane wave shielding effectiveness at 10 GHz, with, a continuous use temperature range of -55°C to +160°C, and resistant to solvents and jet fuels. | |
A high durometer silver-plated, copper-filled silicone capable of 110 dB of plane wave shielding effectiveness at 10 GHz with a continuous temperature range of -45°C to +125°C. |
Compare SSP’s M83528 gaskets to CHO-SEAL products. SSP is not a Parker Chomerics distributor.
MIL-DTL-83528 QPL certified EMI gaskets are used in these and other military applications.
SSP fabricates corrosion resistant EMI gaskets from shielding silicones that we make. They provide resistance to galvanic corrosion, which occurs two dissimilar metals are in contact with each other in the presence of an electrolyte (like water or salt solution) and an electrical current flows between them, causing one metal to corrode preferentially.
SSP’s corrosion resistant EMI gasket materials are shown below. These nickel-aluminum-filled silicones are a cost-effective alternative to silver-filled EMI shielding gaskets. SSP2529 is an offset to CHO-SEAL 6502 and SSP2551 is an offset to CHO-SEAL 6503.
Corrosion resistant EMI gaskets are used in environments where enclosures require EMI shielding and are exposed to harsh environments with moisture, salt, chemicals, or temperature extremes. Other gasket materials can rapidly degrade, but corrosion resistant EMI gaskets maintain sealing and shielding over time. They are used in these and other applications.
Nickel-aluminum-filled silicones exhibit the lowest amount of flange pitting from galvanic corrosion, an electrochemical process that occurs when two different metals are in contact in a saltwater environment. These shielding silicones also exhibit excellent galvanic stability with aluminum flanges.
Soft EMI gaskets are made of soft silicones with durometers as low as 30 Shore A.
They can be made of SSP502-30, a nickel-graphite shielding silicone that is comparable to CHO-SEAL S6305, 6330, 6370, 6371, 6372, and 6308. Also filled with nickel-graphite is SSP502-40 silicone, an offset to CHO-SEAL S6305, 6330, 6370, 6371, 6372, and 6308.
SSP502-40-V0 is a nickel-graphite silicone that is an offset to GORE GS2100 and provides UL 94V0 flame resistance. SSP550-45 is a silver-aluminum fluorosilicone with ASTM E595 low outgassing that is comparable to CHO-SEAL 1287 and 1298.
Like other types of elastomeric gaskets, a soft 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.
Soft EMI gaskets are used in applications that require reliable sealing under low closure force.
Fuel resistant EMI gaskets are made of fluorosilicones for resistance to gasoline, diesel fuel, and aviation fuel (avgas).
Fuel resistant EMI gaskets can be fabricated from a QPL certified MIL-DTL-83528, Type D elastomer and nickel-graphite materials in 50, 60, and 80 durometer (Shore A). SSP also offers two two silver-aluminum fluorosilicones, including a passivated product. Passivation increases the corrosion resistance of the electrically conductive metal particles.
Fuel resistant EMI gaskets are used in military and civilian applications that require resistance to harsh chemicals, including fuels and solvents.
Fluorosilicones combine the high and low-temperature resistance of silicones with the fuel and oil resistance of fluorocarbons. Compounds that are filled with metal or metal-coated particles also provide electrical conductivity and EMI shielding.
Low outgassing EMI gaskets are made of shielding elastomers that meet ASTM E595 requirements for low levels of silicone outgassing, or offgassing, that can occur in vacuum environments like outer space.
SSP’s low outgassing EMI materials include a QPL certified MIL-DTL-83528, Type B offset to CHO-SEAL 1285 and an offset to CHO-SEAL 6502. Low-outgassing flame retardant offsets to GORE GS2100 and GORE GS5200 are also available. In addition, SSP makes shielding gaskets from an EMI silicone for extreme low temperature environments and a silver-aluminum fluorosilicone.
Low outgassing EMI gaskets are used in satellite communications, typically as gaskets for optics, sensors, and electronics that could cloud from silicone outgassing in the vacuum environment of space.
SSP’s most electrically conductive EMI gaskets have silver-coated particles.
SSP’s most electrically conductive EMI gaskets can be made two MIL-DTL-83528 QPL certified EMI silicones that are filled with silver-copper.
There are also three other SSP materials for the most electrically conductive EMI gaskets.
These EMI gaskets are used in a variety of applications that require high levels of electrical conductivity.
The EMI shielding that’s used in automotive, aerospace, and medical electronics must meet multiple design requirements. For example, an EMI gasket that’s used with aircraft may need to resist the splash of jet fuel. Shielding that’s used with EV charging stations may require compliance with UL 94 standards for flammability.
Flame-retardant EMI gasket materials from SSP are made of a shielding silicone with a UL 94 V0 flame rating. They provide an alternative to discontinued GORE products.
Use SSP502-40-V0 instead of GORE GS2100, and use SSP502-60-V0 instead of GORE GS5200.
Reinforced EMI gaskets contain nickel-graphite particles and are reinforced with an inner layer of conductive fabric. They are fabricated from sheet or rolls materials that come in four different inch-based thicknesses: .020, .024, .032, .040, and .062.
SSP offers two composite materials, both of which have physical properties that are superior to non-reinforced elastomers. SSP502-65-COMPOSITE uses a silicone base and SSP502F60-COMPOSITE uses a fluorosilicone base.
Reinforced EMI gaskets are used in applications where there is a risk of tearing.
SSP’s most cost effective EMI gaskets are made from a nickel-graphite EMI silicone.
SSP’s most-cost effective EMI shielding silicone, SSP502-65, supports thinner, smaller, and lighter weight designs. It’s also an offset to CHO-SEAL 6305. This 65-durometer nickel-graphite EMI elastomer offers performance levels that are comparable to shielding silicones with silver-coated particles. Independent test results for salt spray according to ASTM B117 are also available.
These EMI gaskets are suitable for applications where cost is a key consideration.
SSP also makes non-silicone EMI gaskets from a 75-durometer nickel-coated EPDM shielding elastomer. SSP2514-75 EMI gasket material provides excellent ozone and UV resistance along with good compression set and solvent resistance. As with all SSP’s EMI shielding elastomers, customized versions are available in different durometers.
SSP can flash cut, die cut, or compression mold EMI gaskets from the shielding silicones that we make. SSP can also apply pressure-sensitive adhesive (PSA) backings for ease-of-installation.
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 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.
SSP can also cold 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.
SSP supplies mold-able EMI silicones. For frame gaskets, molding minimizes material waste, maximizes material yields, and eliminates the need to bond cut lengths. Fabrication processes like die cutting are efficient, but the cut-out section of a frame gasket can represent significant material waste.
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 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.
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.
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 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.
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.
By their very nature, EVs place a large amount of electrical and electronic content into confined spaces. The radiated and conducted emissions from these systems can disrupt circuits and result in conditions that range from minor inconveniences to dangerous losses of vehicle function. There are sources of EMI outside of the vehicle as well.
EMI gaskets provide EMI shielding and environmental sealing in electrical and electronic enclosures They are made of elastomers that are filled with metal particles or wires to provide electrical conductivity. Typically, silicone or fluorosilicone is used as the base elastomer. Both provide thermal insulation, meaning that they resist the transfer of heat. Fluorosilicones also provide fuel and chemical resistance.
In enclosures, EMI gaskets seal the gap between two mating surfaces, such as a housing and a lid. Like other types of environmental gaskets, they seal out the external environment or seal-in to prevent leakage. What makes EMI gaskets different is that they also seal against conducted or radiated EMI that can interfere with circuits.
When this electromagnetic interference or “noise” reaches the EMI gasket, the signals are negated and the resulting electrical current is sent to ground. Silicone is normally an electrical insulator rather than an electrical conductor, but the addition of metal particles or wire imparts the necessary electrical conductivity.
EMI (electromagnetic interference) and RFI (radio frequency interference) are often used interchangeably. Both are electrical disturbances/electromagnetic emissions that can cause problems with some equipment.
The simple difference between EMI and RFI is that EMI includes any electrical frequency, while RFI is limited to the radio frequency spectrum, which is a subset of the entire electrical noise spectrum. So, EMI gaskets and RFI gaskets basically perform the same function.
Stockwell Elastomers can fabricate EMI gaskets or RFI gaskets for you, depending on your EMI/RFI management requirements.
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.
See these additional resources for more information.
Not all EMI gaskets are made from solid silicones or fluorosilicones.
Beryllium Copper (BeCu) Fingerstock
Pros: Excellent conductivity and spring properties
Use: High-performance RF shielding in enclosures and doors
Metal Mesh Gaskets
Usually made from stainless steel, Monel, or aluminum
Often combined with elastomer cores for compression
Use: Rugged industrial or military environments
Construction: Conductive fabric wrapped over a soft polyurethane or other foam core
Pros: Lightweight, cost-effective, flexible
Use: Consumer electronics, I/O shielding, display bezels
Variants: Different shapes like D-shape, rectangular, or U-channel
EPDM or Fluorosilicone with conductive fillers
Filler Types: Silver, nickel, graphite, etc.
Pros: Better chemical resistance than silicone in some cases
Use: Aerospace, automotive, harsh environments
Construction: Short metal wires (usually silver-plated copper) embedded vertically in a non-conductive elastomer
Pros: High EMI shielding with controlled conductivity
Use: EMI shielding plus environmental sealing (IP-rated applications)
Examples: Silver-filled thermoplastics
Use: Molded or extruded shapes for board-level shielding or custom gaskets
Pros: Moldable into complex shapes, good for low- to mid-level shielding
Combines the strength of wire mesh with compression characteristics of elastomers
Use: High-durability applications like doors or access panels
