Conformal Coating vs Potting: Which Protects Your Board Better?

Conformal coating services › Conformal coating vs potting

Conformal coating is a thin protective film that follows the shape of the board, typically tens of microns thick. Potting, also called encapsulation, fills an enclosure around the board with resin that sets into a solid block. Potting gives the most protection against impact, vibration and tampering, but adds weight and makes inspection and repair difficult. Conformal coating protects against moisture, contamination and corrosion at almost no weight, and the board can still be inspected and reworked. This page compares the two and shows when each makes sense.

Key Takeaways

• Choose conformal coating when weight, size, inspection or repair matter, which covers most circuit boards.
• Choose potting when the assembly faces impact, heavy vibration or abrasion, or when the design must be hidden from reverse engineering.
• Potting is hard to inspect and rework, and the resin can generate heat as it cures.
• Conformal coating does not stop reverse engineering and gives less protection against heavy mechanical damage.

What is the difference between conformal coating and potting?

A conformal coating is a dielectric layer applied to the board and components, conforming to their outer shape. It adds protection against moisture, corrosion, fungus and salt spray without adding meaningful weight or thickness. It is applied by spray, dip or brush, or by vapour deposition in the case of parylene.

Potting places the assembly in an open box or housing and pours a liquid compound around it, usually a two-part resin mixed with a hardener. Once it sets, the compound and the box become part of the product. The result is a thick, solid block around the electronics.

Conformal coating vs potting compared

The comparison follows Rush PCB's published guide to potting and conformal coating, with the UV point from Specialty Coating Systems.

When is potting the better choice?

Potting makes sense when the assembly will see rough handling, impact or heavy vibration, when it must survive abrasion, or when the design needs to be hidden from competitors, and the assembly is not expected to be repaired.

When is conformal coating the better choice?

Conformal coating suits most circuit boards: anything with weight or space limits, anything that must be inspected after manufacture, and anything that may need repair in service. It protects against the threats most boards actually face, which are moisture, condensation, contamination and corrosion, rather than impact. If the environment includes chemicals, heat or flexing, the choice of coating type matters more than the choice between coating and potting. See our conformal coating types page.

Is encapsulation the same as potting?

The terms are often used interchangeably. Strictly, potting means the compound and its enclosure become part of the product, while encapsulation can also describe a compound that is moulded or cast around the part and then removed from its mould. Both give a thick protective block rather than a thin film.

Can you combine coating and potting?

Yes. Some assemblies are coated first and then potted, or coated on one area and potted on another, such as coating a control board and potting a high-voltage section. Our suggestion is to decide what each area of the board needs protecting from, then choose the method for that area.

How Systemation Euro can help

Systemation Euro offers liquid conformal coating, parylene coating and plasma cleaning, with masking, inspection and a certificate of conformity if required. We do not currently offer potting. If you are deciding between the two, send us the assembly details and the environment through our conformal coating services page and we will tell you whether a coating will do the job.

Frequently Asked Questions

Is potting better than conformal coating?

Only for some jobs. Potting gives better protection against impact, vibration and abrasion, but adds weight and makes inspection and repair difficult. For most circuit boards, conformal coating gives enough protection at a fraction of the weight.

Can a potted board be repaired?

It is difficult. The resin encases the board, so inspection and rework are hard. A conformally coated board can be inspected and, depending on the coating, reworked.

Does conformal coating stop reverse engineering?

No. The board remains visible through most coatings. Coloured potting compounds are used where the design must be hidden.

Is conformal coating waterproof?

Liquid conformal coatings are generally described as moisture and humidity resistant rather than waterproof, and coating that is too thin can let water in. Potting gives a fuller seal. If immersion is a requirement, tell us when you ask for a quote.

Sources: Rush PCB, Which is Better for PCBs: Potting or Conformal Coating; Specialty Coating Systems, Comparing Parylene and Acrylic Conformal Coatings (UV traceability, rework). Supplier and manufacturer sources.