Aluminum skin delamination

[skybear4]

The aluminum skin is coming unglued on the sides of my trailer. Would like to have it professionally repaired. Any suggestions or options would be appreciated.

[citylights]

The aluminum skin is coming unglued on the sides of my trailer. Would like to have it professionally repaired. Any suggestions or options would be appreciated.

It is a really bad idea to glue aluminum to wood. The two have different expansion ratios... The metal expands a lot when it gets hot, but the wood does not. This makes the glue between the aluminum and wood fail in just a couple of years.

The better construction technique is to "float" the aluminum. In that case the aluminum is not glued to the wood sides. Instead it is held on by the trim, which is screwed to the wood. A flexible sealant like butyl tape goes between the trim and aluminum skin.

A professional repair would be to add the trim to hold the aluminum skin on.

[48Rob]

David,

Can you post a couple pictures of the trailer?
It is always much easier to offer quality advice with photos/accurate information.

I would be concerned about why it is coming loose, and determine the repair plan from there (either reglue, or float).
It could be a poor glue bond from many causes, moisture intrusion included, but without knowing for sure, attempting to fix it may or may not be successful.

Rob

[skybear4]

having trouble posting picture. Can you send me your e-mail?

[48Rob]

David,

Here are the pictures...still pretty small, but perhaps clear enough to get the idea.





It looks like typical "oilcanning"
Does it stay this way, or get wavy and relax?

Rob

[skybear4]

It stays waving and has been getting progressively worse. I think bumping along down the road has contributed
to the problem.

[skybear4]

Not familiar with "oil canning"?

[48Rob]

Dave,

"Oil canning" is when the metal expands/swells at a different rate than the substrate it is attached to.

Plywood, for example expands and contracts at a different rate than aluminum.
Since the aluminum expands more, but is still attached at the edges, it swells or ripples between the mounting points.

When an aluminum skin is floated, it is attached with minimal fasteners, and allowed to float across the majority of the substrate surface.
The aluminum still expands just as much, but since there are few mounting points, it is able to expand a little under the lip or edging of the trim that holds it on around the edges so that you don't see the swelling/rippling as much, if at all.
The use of a sealant/putty that can withstand the expansion and contraction of the metal, and itself allows the seal to stretch many many times, but not break.

What I see in your pictures offers three possibilities;

One is that the trailer body is unable to support its own weight and is causing the rippling from being structurally weak from poor construction methods (very unlikely)
Two, the structure is very weak and the metal has delaminated from water damage (possible, but not likely).
Three, the metal was glued to the substrate and the glue was not able to withstand the expansion and contraction which caused the metal to separate in that area (very likely).

The best "fix" would be to remove all the trim, windows, doors, etc. and finish separating the skin from the substrate.
Once freed up, the glue must be neutralized or covered with a barrier so the skin, old if not damaged, or new if it is, can be floated across the surface.

Nice looking trailer!
Is it new? If so, the manufacturer may take some responsibility, or at least be able to offer tips assuming that some of their other trailers have suffered so.
Several owners here on the board have also dealt with this issue, I'm sure they'll chime in soon (Sunday is always kind of slow...).

Rob

[skybear4]

Rob, thanks for the in depth analysis. The trailer is about 1-1/2 yrs. old. I have put in a call to the mfg. to see what
they have to say. Sounds kinda pricy to gets things up to snuff and not sure who locally to turn to for something
like this, metal fabricator or trailer mfg.? I'm not skilled enough to tackle something of this magnitude.

I don't think I have water damage or leakage involved but am now noticing some separation of the silicone caulking from the skin to the edging. I'm concerned that may lead to water damage.

[ssrjim]

Mine does that when it is hot out but as soon as things cool off it goes flat again. I'll call it normal for mine but am not bold enough to call yours normal.

[skybear4]

Well, maybe the way to go if this is somewhat normal is to try and camouflage it some how. Any ideas?

[doug hodder]

I used some .025 aluminum skin on one of my standy builds, however it's just flat material. When it gets really hot like 90+F...it looks like someone bounced a basketball on the roof. When it cools down at night, it all lays down and looks just fine. A later build uses .040 and it will get a bubble on the side in hot temps, but again, lays down once it cools. the sides on that one are 2 toned with a very dark charcoal paint. It really soaks up the heat. I don't even attempt to adhere the skin to the substrate as it will just want to pop and do it's thing in the heat. That's one of the reasons that they used a ribbed type pattern in a lot of the canned hams and smaller camper trailers. It gave an air cushion and some ribbing for strength so it wouldn't want to go all crazy. You could install a false "louvered small vent" available at marine shops to make it appear that it's got a vent, when it's real purpose is to allow you to shoot some screws into the bubble. chances are, it's still going to do it's thing and the bubble will only move around a bit. Others opinions may vary. Doug

[citylights]

Classic Oil Canning from heat expansion. Too well fixed at all edges, not enough room for the aluminum skin to expand when heated by the sun.

Some have recommended not hard fixing the bottom edge to allow expansion in that direction. Some have recommended cutting and installing the aluminum in the sun, so it is installed at the largest size and only shrinks. (That is what I did.). Others have recommended cutting the aluminum 1/8th inch small and covering it with the trim to allow space for expansion.

Most just live with the oil canning.

[ctstaas]

Hi Everyone, My TD is painted but I want to skin the next one with Al. but want to make sure I understand everything I know before I start. Good point with the two expansion rates, but should we consider a third, the adhesive expansion rate? I plan to float but the glues expansion could be applicable to other parts of my TD? Has anyone tried applying the skin when its hot out? I know when the Golden Gate Bridge was built the crews had to wait for the ambient temperature to be just so for the parts to fit together properly. Could I pre-heat the skin before application?
Enjoy, Chris

[halfdome, Danny]

I watched a Camp Inn oil can in the California sun a few weeks ago, not a pretty sight.
From my understanding they float the aluminum.

Some will not agree but...
I randomly sand the back of the .040 aluminum with 80 grit sandpaper (pneumatic DA sander) to give it tooth for the glue to adhere.
I apply 3 coats of Wilsonart contact adhesive to both surfaces.
I have pre made plywood boxes to position the aluminum at the correct height on the level teardrop.
I use 3/8" dowels to stand the aluminum off the teardrop wall and tack the center & then hand roll the sheet into the cured glue.
It needs methodical massaging to get a great bond.
Never had any oil canning issues.
Danny