Epoxy FAQs

What is a potting compound?

Encapsulants (potting compounds) are normally applied thicker than conformal coatings. Due to the thickness, it does not conform around the board, instead taking the shape of a defined area by utilising a mold or a dam.

To compare, conformal coatings are normally a relatively thin layer (25-200µm), where the material conforms to the shape and components of board. For a typical CVD coating, the thickness can be even less.

Potting compounds are not necessarily transparent. The conformal coatings are normally transparent, so all components remain visible.

Why are epoxy potting compounds used?

A potting compound encapsulates a product completely and protects it from the environment.

Many potting materials can be used to improve electrical insulation, provide environmental protection from moisture, water and chemicals and prevent mechanical damage from thermal shock and vibration.

The potting compound also used as intellectual protection, restricting and preventing analysis and information extraction on the product.

Finally, epoxy compounds can be used to mitigate tin whiskers.

In fact, it has been shown that potting/encapsulation materials are the most effective tin whisker mitigation strategies, as the increased mass of the coating material and impervious nature of the fillers offers maximum protection against even the most aggressive tin whisker growth.

They create a physical barrier that slows tin whisker growth. Therefore, it is hard to penetrate these coatings and they make it difficult for tin whiskers to begin growing.

If any tin whiskers do grow, they are constrained and held in place, preventing them from causing unwanted electrical connections that can destroy a board.

What sectors are epoxy coatings being used?

There are many different sectors that potting compounds are used. They include sectors such as:

  1. Medical
  2. Aerospace
  3. Defence
  4. SMART Grid
  5. LED
  6. Industrial
  7. Automotive
  8. Tin-whisker mitigation

What products are actually coated

Many different products are coated in epoxy coatings. They include:

  1. Transportation electronics
  2. Automotive vehicles
  3. Industrial controls
  4. Medical devices
  5. LED circuitry
  6. Aerospace and military electronics
  7. FIPS (Federal Information Processing Standards) electronics requiring high security protection

What are five key differences between an epoxy potting compound and a conformal coating for protecting an electronic printed circuit board or assembly?

  1. A conformal coating is extremely thin compared to an epoxy potting compound. Conformal coatings are normally a relatively thin layer (25-200µm), where the material conforms to the shape and components of board. For a typical CVD coating, the thickness can be even less. Due to their thickness, a potting compound does not conform around the board, instead taking the shape of a defined area by utilising a mold or a dam.
  2. It is difficult to waterproof a circuit board with conformal coating. This is due to the relatively low thickness of the coating exposing components and not covering the sharp edges adequately. A potting compound applied at a few millimetres can easily waterproof a circuit.
  3. A conformal coating is normally transparent so you can see the components below the coating. A potting compound can have a pigment, filler or dye within the coating to prevent the components being seen.
  4. A conformal coating is relatively easy to repair compared to an epoxy potting compound. The material tends to be softer and thinner. An epoxy coating is hard and also very thickness. This makes it difficult to remove.
  5. The combination of differences 3 and 4, the lack of transparency and the hardness of the coating make a potting compound ideal for protecting IP (Intellectual property) of a circuit and provide significant security. A conformal coating conversely is poor at achieving this.