Aluminum roof - bonding options?

[Bludacious]

Hi everyone,
I'm getting ready to put a new custom arched roof on my Jammy made out of lapped 18ga or 20ga 4x8 aluminum sheets over lauan on a steel frame, similar to how a school bus is built.

I don't want to use the OEM red contact adhesive since I've read online & been told by my local shop that over time the bond it makes turns acidic and eats the aluminum from the inside. I'm pretty sure this is what totaled the original metal roofs on both my older rigs to begin with. Is this information out of date? Will a newer neoprene adhesive like 3m 1357 not cause this?

My other question was if I should just 'float' the aluminum pieces? Either way I plan to screw/rivet the panel edges anyways. My main concern was that this would leave a small gap where condensation could build up and rot the lauan. I've thought about coating the wood with epoxy before I lay the aluminum down, but I think that would just trap any moisture inside forever and cause more problems.

I'm almost literally dizzy from researching so many different industrial adhesives. Any that look like they would work in place of the red stuff are pretty expensive, difficult to apply or both. Thoughts?

[slowmachine]

My 20 year old MH has some serious water damage to the luan backers in the exterior walls. The butt joints between panels are glassed and epoxied, and they are undamaged. I would not hesitate to use an epoxy sealer on the luan. You can easily test by epoxy-coating a single luan panel and leaving out in the weather for a while.

[azpete]

water based contact glue will work. you can buy it from any lumber yard, or as i did, a countertop mfg. use a paint roller to spread it on both the roof and the aluminum. i have replaced many aluminum roofs, and sidewalls this way. none had the corrosion problem.