Conformal coating dip tank or other conformal coating options?

[Rat_Patrol]

Before I go and build one myself, are there low cost options out there?

Right now I rattle can spray all my PCBs with urethane conformal coating, but I need to upgrade to a dip tank for productivity reasons, not to mention better coverage under components.



Otherwise, I'm also open to completely new thoughts on waterproofing my PCBs. I have some areas to avoid; PTH screw mounts which act as an earth grounding point, so they need electrical contact. Right now I put a masking tape dot on them prior to spraying. I also have some connectors that can't get coating on the contacts. The PCBs have multiple THT MOSFETS on heat sinks that need waterproofing as well, so its more than a 2D waterproofing job.

Urethane is preferred, but I could also use epoxy. Acrylic won't cut it, and I'd rather not use silicone.

[HHaase]

All depends on your budget.   You can sometimes find a used Nordson or PVA coating machine for sale with the right atomized or film coat spray heads.   I will say that really no spray type system will get you good coverage underneath components though,  you generally encapsulate around the edges and seal off the underside.

Dipping, if thin enough of a viscosity, will definitely be quick and coat anything not masked.  Though cure time tends to be longer and you need to set up a way to hang them for drips.

If penetration is the biggest concern, then Parylene may be something to look into.  I've never used it myself, and apparently you need to be very thorough about what you mask,  but it'll coat everything with a consistently even layer of material.  I don't know how complex the process is though.

[Gribo]

Consider Parylene conformal coating, it might give you better results than Urethane.

[Rat_Patrol]

Looked into the Parylene, doesn't look like it will be a good fit for my operation.

Guess I'll just have to build myself a dip tank.