I was playing around with PCB conformal coating for a client project. Wanted to share my takeaways.
Conformal coating is a thin, non-conductive layer applied to the surface of a PCB. It conforms (hence the name) to the board’s contours, including components and traces, forming a protective barrier. This coating acts as the PCB’s protection armor against environmental damages like humidity, dust, or chemical exposure.

Why use it? It provides humidity protection. When your device needs to work in high-humidity areas, condensation can happen on the PCB surface to short the circuits and can even erode the tracks with continuous exposure. In industrial or automotive environments, exposure to chemicals like solvents or oils can degrade PCBs. Coatings provide a barrier against that. Some coatings are done all around the PCB not just as a thin layer to make it mate with an enclosure to be a temperature insulator and to provide vibrational rigidity to the PCBs. Also used as a high-voltage insulation barrier.
Conformal Coatings are of a few types:
Acrylic: Affordable, easy to apply, and repairable. Good for hobby projects. You can solder/rework them if needed. Usually transparent and comes with and without UV glow. UV glow is a cool feature that will allow you to see where the coating has been applied under UV light(Check pics).
Epoxy: Strong and durable, but rigid when hardened. They are often seen as black material covering bare dies or chips, commonly used to prevent reverse engineering of PCBs as they are difficult to remove without aggressive chemicals and significant effort. You will see them a lot in defense products.
Silicone: Great for extreme temperatures and flexible surfaces. Common in automotive or aerospace applications.
Common methods of applying it include spray coating, brush application, dipping, or selective dispensing by machines for large volumes. The application really depends on the type, MoQ volume, thickness and precision needed.
Feel free to try them out on your next projects. They can make or break a product in the right environmental conditions!
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