best technique for plywood top/side sealing

[gene so]

Hello,
I am building a 9 ft. trailer with custom frame and steel tubing framework plywood sides and top with wood uprights, framing and insulation. I have spent time living in the Olympics with its 212 inches of rain annually and have seen campers with moss groing on them. Retired to the SW I still want to make a camper that is as totally resistant to leaks as possible. I still have not settled on an outside skin, but want to concentrate on the seal of the plywood jts.
So if you have a superior method, I am not against extra time and effort to get these jts. as leakproof as possible. Since the winds blow so steadily here I assume that anything built to resist leaks and is insulated should be quieter at night.
Thanks in advance,

Gene So

[Tomterrific]

JTS. = joints?

My plywood joints were sealed by using liberal amounts of PL construction adhesive. This is a thick urethane glue that sets like plastic. I fingered squeeze out to seal the outside of the joint.

All joints were backed by a cleat of sorts for more strength and gluing surface. I used small cut blocks around the curves.

I saturated the surface of the plywood with solvent thinned polyurethane to penetrate and give the initial seal before paint.

All exterior joints were caulked with urethane caulk before painting. All metal (vent, windows, hinges) were set in non hardening rope caulk.

T

[les45]

I used CPES to seal all the plywood skins on my Super Bee with a heavy application on all joints and cutout edges. I then applied a 4" fiberglass tape on all joints with an Aeromarine 300/21 epoxy system. After sanding all the joints, I applied two coats of Zinsser oil based primer and three coats of Rustoleum over the entire exterior. You can see more details on page 5 of my journal at this link: http://tnttt.com/viewtopic.php?f=50&t=49333

[rowerwet]

http://m.instructables.com/id/Poor-Mans ... -weatherp/ this coating is still as strong and waterproof as the day I put it on in 2011.
In 2014 I peeled some of it back to attach it to a new trailer, the wood was as fresh as the day it went on

[bherron1]

I dont think for sealing plywood u can get any better than epoxy resin and fiberglass cloth.

[HarryL]

I sealed my standie with three coats of slow setting epoxy resin. Sanded it smooth and than spray painted it with a two part boat hull paint. So far so good!