Does anybody use a conformal coating on finished boards ? Is it safe to use on SMD components ? They all seem to apply a very thin acrylic layer which isn't conductive, but before I buy one and ruin a board, would be nice to know others have used them successfully.
An example is: https://www.farnell.com/datasheets/2614587.pdf but there is a good choice, seemingly at different prices for very similar products, maybe with different test certifications.
An example is: https://www.farnell.com/datasheets/2614587.pdf but there is a good choice, seemingly at different prices for very similar products, maybe with different test certifications.
@hal4287 used it successfully on boards with one dual SMD op-amp and a bunch of through-hole components, see posts #106...#108 of https://www.diyaudio.com/community/threads/need-advice-for-a-weird-project.352655/post-6340375
Use it all the time. For my high voltage constructions (such as tube amps running up to 2.3kV plate voltage) it's a must. For those applications I use a conformal coating called Corona Dope.
The whole purpose of conformal coating is to coat parts on PCBs to keep out moisture and particularly condensation (or as above sometimes for greater voltage handling). The problematic parts aren't SMD, its the one's with empty space inside, preset pots, relays, connectors.
Coating is also good for preventing tin whiskers.
I use it on everything at work.
I use it on everything at work.
I worked for Delphi Automotive twenty years ago. At the time, we were trying to upsell Toyota on thicker coating. They asked how much thickness guaranteed how much more life. We didn't know the answer so Toyota made us learn the answer. Thickness of the coating had very little effect on the development of tin whiskers. Cleanliness of the boards before coating, however, had a large effect. Sadly, I don't know much about the different cleaning processes applied but clean those boards before coating then
Yes - we had some RMA issues with a customer (name omitted to hide the guilty) who did washing machine controllers. They used no-clean flux and didn't bother to clean off the boards before applying a polyurethane conformal coat. That casued all sorts of issues with current leakage between traces/components, and it turned the conformal coating black near the board surface.
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