Conformal Coating PC Parts?

Question

I couldn't find any topics relating specifically to this sort of thing, and even tried asking folks over on Reddit at /r/buildapc, but I didn't get many responses or many people know if it would be possible to safely apply a conformal coating to PC components that would or may be exposed to water when doing a watercooled PC build. This is mainly to try prevent any accidental leaks from damaging components while doing a watercooled pc build.

I've read many other topics of conformal coatings being applied to smaller electronics and works fine even after being exposed to water or moisture as if nothing ever happened. My searches brought be to this topic: Waterproofing electronics by dipping into polyurethane or lacquer.

Now obviously I'm not planning on dipping components straight into anything, I'll be instead doing a spray-on application for a thin evenly coating. I just need to know if I can apply the same kind of conformal coating and everything working out alright, for example this product here which is a high temperature silicone based conformal coating which seems like the best option for PCB components. I have read other bits that some conformal coatings may contain different solvents that may not be suitable for electronics and such that may be exposed to water or moisture. Nobody's probably ever attempted to do this sort of thing for PC components by applying a silicone based conformal coating to protect against water and moisture, since this is a larger scale for electronics, but it's something I'm willing to experiment with.

with Water Cooling PC builds there is no direct exposure to water, and it's assumed that all fittings are properly seated and watertight sealed with O-rings, but there's never a 100% guarantee that they won't fail unexpectedly and accidentally leak. Now I'm not interested in hearing people say things like "Oh well if you're worried about water leakage then maybe you shouldn't do watercooling." Say what you will, I've heard it all before, and this is an experiment to try something nobody's probably ever attempted before just to see if this works in an application like this.

Answer 1

There are coatings meant for this purpose (that is, coating circuit boards to improve robustness of the system with respect to corrosion and condensation etc.) I cannot imagine you running into a lot of issues with solvents using those products. Consult the datasheet to be sure.

PCBs used for computers have a lot of controlled impedance traces for different busses, like PCI(e), your DDRx RAM, high-speed busses to connect to the chipset, etc...

I don't know how controlled these impedance are, but coating them will effect this impedance.

In addition, coating everything will add thermal resistance to the system. This could mean that devices that were cooled through the PCB before with big copper planes no longer receive adequate cooling. This could result in components overheating and the board no longer functioning as it should.

And of course (but I assume this is obvious) - you need to make sure that all the connectors and screw lugs are protected so they don't get coated. The locations where you screw the motherboard to the case are usually connected to some form of ground, and if this is not connected I think this could result in issues with EMC.

And I would be very surprised if there are no manufacturers out there that have conformally coated motherboards for industrial or other "high reliability" applications.