Some of my projects need to live outside for long periods. Sometimes, moisture gets into the enclosures. That means that a circuit board might be sitting around in contact with water for hours on end at upwards of 100F.
I've noticed that solder joints can start to corrode, and recently moisture made it under the solder mask on a board and actually ate through one of the traces, breaking the circuit. I know the ideal answer is to make a perfectly sealed enclosure, but I'd like to toughen the boards up a bit as a second level of defense.
Can anyone suggest some tips and tricks for making PCBs more corrosion resistant? Does scrubbing off excess flux help? What about spray acrylic sealant? Special solder?