Posted by Sherman in Idaho [108.162.245.30] on Tuesday, July 12, 2016 at 16:15:22 :
In Reply to: Help with wood floor in Carryall posted by WarEagle [108.162.237.58] on Tuesday, July 12, 2016 at 14:33:24 :
If I was going to varnish it, I might soak it well, especially the ends, with something like Danish oil before the wood is assembled. It's like a thin varnish that soaks in a lot better. I use it on tool handles that will be left out in the weather and it seems to hold up better than varnish and protect better than something very light like sanding sealer. That might work okay for painting over with oil-based paint as well, but I haven't tried it. Kilz doesn't hold up very well in exterior applications, in my experience. It's a great interior primer and stain blocker (don't even waste your time thinking about the water-based variants, though). Generally, a slow-drying alkyd oil primer is best for exterior wood.
There's no such thing as truly "sealing" wood because any holes or end grain will let water in, and the wood will eventually shrink and crack and provide more ways for water to get in. Various treatments will help but nothing is a real seal. If there's any way you prime and paint the wood after ALL the machining is done, but before you install it, that will do way more good than finding the right miracle product to put on after the wood is installed.
Since you don't need much, cost is probably not a big issue, so you might want to check with a good industrial-quality marine supply place, if you have one near you, and see what they recommend for wooden boat decks. It would surely be better than anything you'd find at a lumber yard.
Be sure to not used galvanized bolts. There's some weird chemical reaction that happens between zinc and oak (and not other woods) that is bad for both of them. It's almost like it rots the wood, although I don't understand why that should be. Stainless (cheap on-line these days) and bronze (from the marine supply) are fine, but galvanized should never be used in contact with oak.
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