Laminating aluminum to plywood

[Caster]

This is difficult to explain but, I'm building a small enclosed trailer. Kinda like those little Uhaul trailers.

I've got the frame built including the body skeleton. The body skeleton is made from 2x2x 1/8 thick steel angle. I want to use plywood to make the walls and door. I have a big roll of 24" wide aluminum like contractors use for siding. I'd like to laminate the two together, then bolt it to the inside of the angle to make the walls. I'll caulk the crap out of everything and then I will paint everything with bedliner when I'm done.

Just curious what you guys think would be best for an adhesive. Regular contact cement? I'm limited to whatever Lowes has, I got a gift card ;) Edited June 24, 2015 by Caster

[A.J. Holst]

I like Dolo's suggestion as long as you are certain of no water intrusion.

 

Spread it with a small notch trowel and "roll it" to ensure adhesive transfer.

 

The only downside to tradition flooring adhesives is they are organic, meaning if the repeatedly get wet, they will begin to break down into a gooey mess.

 

An epoxy would be the best choice

 

Be sure all surfaces are clean and free of oils, dirt, etc.

[MacGyver]

I'd go with a two part epoxy that's going to cure as a part of a chemical process. Something like a West System 105.

[Hozzie]

Yep, two part epoxy and roll it on.  The pain in the rear is the continual rolling you need to do until it is good and set.  Letting them each get tacky will help a lot.

[monkeylizard]

 

 

Seriously though, what MacGyver said. West System 105 resin with their 206 slow hardener. It's made for boats so it will withstand some crazy weather. Roll it on, then clamp it all together and put something heavy on top of the aluminum. Let it sit for a day and *poof*. All done.

Edited June 24, 2015 by monkeylizard

[peejman]

What they said.... some sort of 2 part boat epoxy.  It'd be best if you could rough up the surface of the aluminum.  Media blasting would be the easiest, if you have access to a blaster.  If not, scuff the surfaces with 120-240 grit sandpaper and the wipe it down with an acetone soaked rag.  Think about some way to clamp the pieces together while the epoxy cures. 

[Caster]

I can lay another sheet of plywood on top and stack about 20-30 E load range truck tires on top while it sets. That's no issue.

[Omega]

Looking at some laminated boards that have the skin peeled off, they just have lines of some red glue that were holding it together.  None of the ones I have seen have had an even spread of glue, though it wouldn't hurt to do it that way I suppose. If its going to have edge and corner protectors the skin should stay put either way as long as the glue sets properly.  If you want to use the proper glue you may want to give one of the trailer builders a call, they may just tell you what they use.

[MacGyver]

With a good Epoxy like West System, you shouldn't need that much weight on top of it - just try to get the air out best you can and don't worry about it too much.  Since you're not sandwiching they plywood on two sides with waterproof material, moisture should still be able to vaporize and leave through the inside of the trailer.  You shouldn't have to worry about rot like you do when you sandwich wood.  It's not cheap, but a little goes a long way.

 

You're going to want the slow hardener.  In this temperature, the pot life is going to be shorter anyway, so do it in the evening or early morning.  And, with epoxy like this, once it gets tacky, it's too late.  When that stuff cooks off, you're starting over.  Mix up as much as you need and not any more.  Do it in batches.  Pay specific attention to the ratios.  Get both sides clean enough, and you should get good adhesion.

 

I don't think I've got any slow cure hardener, but I should have some pumps that ensure the proper ratios if you want to borrow them.

 

All that said, for a system like this Liquid Nails or some variant will probably work fine, too.  Maybe use some screws or rivets to mechanically bond them, too and call it a day.

[TNWNGR]

The West System recommendation is the route I'd take and I reaffirm you want all of the air bubbles removed from between the laminated surfaces. Even with this though I believe you should seriously consider riveting between the exposed two metal surfaces of the two metal sheets affixed to the plywood. This provides structural rigidity and minimizes delamination, take a look at some commercial trailers. You'll find exposed rivets and filled rivets.

[Caster]

Thanks MacGyver. 

 

I have a bucket of latex sealer I thought about sealing the whole sheet but I think that would be counterproductive.  Like you pointed out, it makes more sense [now thinking about it] to allow the plywood to breath on the inside.  

 

Thanks to everyone.  I really need to get back to this little project and get it done. 

[monkeylizard]

Pics when you're done, or it didn't happen.  :D

[MacGyver]

Yeah, turns out the good Lord is a pretty decent engineer.

 

Coming from an education in naval architecture and a real affinity for old wooden boats, rot happens when we seal both sides of a piece of wood and don't give the moisture anywhere to go.  Think about the old lobster boats and the like.  These things were wood that had the seams "caulked" with a natural cordage like sisal and that's really it with the exception of some paint on the outside.  The water would swell the wood and the cordage and it would be watertight so long as it was kept wet.  Let it dry out and you;d have problems.

 

On your trailer, the issues would really be in air spaces between the aluminum and the wood.  If you've got moisture in there, that's where the rot will start if you don't fill them in.  

 

Don't over do it, though (to the extent that this is possible for you :))  As was mentioned above.  Most commercial manufacturers are going to put down a couple of lines of glue and call it a day.  You're not worried about passing it down to your heirs.  Good enough may really be god enough in this case.

[Caster]

http://www.tngunowners.com/forums/topic/88825-my-expedition-trailer-project/#entry1280137

 

 

I started a build thread for the whole trailer so ya'll can follow my halfassed work.   :rofl:  :rofl:  :rofl:

[Ron Padilla]

the rivets you see on freight trailers are called buck rivets and takes 2 people to do it, they are not done with a conventional rivet gun. However you could use a rivet gun but then you would have to use some silicone sealer in the center of the rivet to ensure its water proofing.

[gregintenn]

Nails? :shrug:

 

 

There's bound to be an episode of the Red Green show that covers this. :D

Edited June 24, 2015 by gregintenn

[Monkeyman2500]

Good ideas here. I'm gonna have to remember that West system for future projects.