How to avoid de-wetting of conformal coating

De-wetting is the where the conformal coating material refuses to wet the surface of the circuit board that it has been applied to in an even way. The coating ends up being patchy.

The de-wetting effect tends to act locally due to local contamination.But, it can be a global affect right across the board.


De-wetting of the conformal coating can be localised or all over the circuit board.

There are many causes of De-wetting in Conformal Coating.

These include contaminants such as residues and oils, and processes such as soldering and cleaning.

To find out more click conformal coating de-wetting.

Need help with your process?

Contact us at Nexus and we can help solve your issues.

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Nexus Newsletter Feature: Conformal coating Defects – Why Do They Occur?


In conformal coating there are many common failure mechanisms in conformal coating including capillary flow (scavenging), delamination (loss of adhesion), cracking, de-wetting, orange peel, pin holes, bubbles and foam. This article briefly looks at reasons each of the defects occur in processing with potential solutions to avoid them in the future.

Click FEATURE “Conformal coating Defects – Why Do They Occur?” to read the article.

Ask The Expert: Dr Lee Hitchens, Nexus on Key Conformal Coating Material Challenges

“Out of all the Key Material Challenges I see on a regular basis, one of the most prolific is difficulties in adhesion to solder resist or to no clean residues and contaminants.“
 “It can be as basic as the coating just will not stick to the PCB or it runs away from areas on the PCB. At other times, it’s interpreting just how well the coating is stuck and determining if it’s good enough for the customer? Normally, this cannot be answered instantly and leads to some serious thinking!”

Visit the Nexus Associate Experts Section and read what other experts have to say about conformal coating material challenges.

Bitesize Nexus Help: The Biggest Cause of Conformal Coating De-wetting Defects

The biggest single cause of de-wetting (a lack of adhesion) of conformal coating on a printed circuit board is silicone contamination accidently introduced in the production line. The silicones can come from many areas including RTVs on the bench and lubricants for machines.

Contact Nexus Consultants for more help on silicone conformal coating de-wetting