Gaskets for Electronics

The Shielding Solution: A Guide to Choosing RFI and EMC Gaskets

In our hyper-connected world, electronic devices are packed closer together than ever before. With components shrinking and frequencies rising, electronic enclosures face an invisible but chaotic enemy: Electromagnetic Interference (EMI) and Radio Frequency Interference (RFI).

Without proper protection, electronic systems can suffer from signal degradation, data corruption, or total system failure.

The frontline defence against this interference? RFI and EMC gaskets.

Here is what you need to know about these critical components, how they work, and how to select the right material for your next design.

What are RFI and EMC Gaskets?

An EMC (Electromagnetic Compatibility) or RFI gasket is a specialised conductive component used to seal gaps in electronic enclosures.
Even the most precisely machined metal enclosures have microscopic imperfections, seams, and joints. These tiny gaps act as slot antennas. They allow high-frequency electromagnetic energy to leak out or penetrate the system.
A conductive gasket fills these voids. It establishes a continuous, low-resistance electrical bond across the enclosure joints. This creates a complete Faraday cage that seals the interference inside or out.

Key Material Categories

Choosing the right material is a balance of mechanical requirements, environmental factors, and shielding performance. The industry relies on four primary gasket types:
1. Conductive Elastomers
These are silicone or fluorosilicone rubbers loaded with microscopic conductive metal particles (such as nickel-graphite, silver-aluminium, or copper).
  • Best for: Applications requiring a combination of high EMI shielding and an environmental seal (protection against dust and water ingress).
  • Common Use: Military communications, aerospace systems, and outdoor telecom towers.

2. Wire Mesh Gaskets
Constructed from knitted metal wires (like Monel, aluminium, or tinned copper-clad steel), these can be all-metal or formed over an elastomer core.
  • Best for: High-level shielding at a lower cost, especially where environmental sealing is not a priority.
  • Common Use: Heavy industrial machinery and commercial electronic cabinets.

3. Fabric-over-Foam (FoF)
These gaskets feature a highly conductive fabric wrapped around a soft, resilient polyurethane or silicone foam core.
  • Best for: Low-closure-force applications where heavy compression could deform thin plastic or metal enclosure walls.
  • Common Use: Laptops, servers, medical displays, and consumer electronics.

4. Beryllium Copper (BeCu) Fingerstock
Metal strips engineered with flexible, spring-like “fingers” that provide exceptional electrical contact.
  • Best for: High-cycle applications where doors, panels, or drawers are frequently opened and closed.
  • Common Use: Data centre rack enclosures and shielded testing rooms.

Critical Factors for Selecting a Gasket

To ensure your enclosure passes regulatory testing (such as CE, FCC, or MIL-STD-461), consider these four parameters during the design phase:
  1. Shielding Effectiveness (dB): Identify the target frequency range of your device. Different materials perform better at specific frequencies (e.g., GHz range vs. MHz range).
  2. Compression Force: Soft foams require very little pressure to seal. Loaded elastomers require significant clamping force to ensure proper electrical contact.
  3. Galvanic Compatibility: Ensure the metal particles in your gasket closely match the metal of your enclosure. Mismatched metals in humid environments cause galvanic corrosion, destroying the electrical bond over time.
  4. Environmental sealing: Determine if your device needs an Ingress Protection (IP) rating. If it must withstand rain or pressure washing, a conductive elastomer is mandatory.

Conclusion
RFI and EMC gaskets are not an afterthought—they are a critical design element. Integrating shielding requirements early in your enclosure design saves costly redesigns, failed compliance tests, and product launch delays.

With experience dating back to the 1970’s, EAS today are working hard to win business from the Electronics sector, both here and overseas.

From simple dash-cams, internet routers and phone systems, through to drones, satellite systems, and electronic defence – we intend to be working with the best !