Can do, although you might be better off using a hard conformal compound (black stuff used for potting electronics) where possible. It has a lower viscosity an

Can do, although you might be better off using a hard conformal compound (black stuff used for potting electronics) where possible. It has a lower viscosity and is less prone to bubbles. I'm not sure how much small bubbles would actually affect it, though. There's one other good reason to use conformal coating: it has very little change in size when it dries. There are a few spots on the board that would be affected by that, most importantly the load capacitors for the timekeeping fork. Ceramic capacitors have a piezoelectric effect and change shape ever so slightly (they stretch and squash, alternately contracting around their midsection and then expanding). It's not enough to break the solder or the epoxy but if you pot them it changes their apparent capacitance, which will change the frequency of timekeeping. Probably not enough to matter, but still measurable. Large inductors have similar problems and can eventually break loose from epoxy.