When I painted over some oak chairs for outside this is what I did:
- cleaned the surfaces with a damp cloth
- used 120 grit sandpaper (from what I remember) to scuff the surfaces and knock down the raised grain from the previous step.
- wiped the surfaces with a slightly damp cloth to get most of the debris from sanding off.
- sprayed on primer (I like spray cans, so much quicker than brush)
- sprayed on 2 coats of enamel white (to make sure I got all the areas)
- put on a coat of spar urethane similar to Helmsman
I don't baby them at all. They've been out in the direct sun for the last 3 years in Vegas and still look great. I know your in a humid area, but this might work for you too. Hope it at least gives you an idea where to start.
Trying to keep all my fingers and toes Personal site