I think Mike was suggesting to use the PlastiDip on the outside of the plastic box only, as a weather sealant for the wire entry, not as a conformal coating on the circuit board or insulator for any bare conductors.
Sealing the plastic box at the lid and the wire entry / grommet with silicone sealant should be good enough for making it splashproof. We don't really need to make it submersible.
Sealing the plastic box at the lid and the wire entry / grommet with silicone sealant should be good enough for making it splashproof. We don't really need to make it submersible.