I want to use a pulse width modulator to replace the on- off switch on my modified electric trolling motors. (I take disabled vets out on motorized kayaks). The modulator works great but, I need to water proof it somehow. What's the best way to do this? What material should I use ? How do I apply it and what should I not apply it to? From my research, I understand some of the issues such as using an epoxy for instance that is thermally but not electrically conductive and that has minimal shrinkage when it dries.
Consider one of 3M's Novec coatings. Ive used them before they do a good job of protecting the electronics. After all that's what it is designed to do and it does not hurt heat dissipation much. The hardest part will be getting a good enough coating on the potentiometer.
Be sure to research which coating works best for you