Adhering pvc-coated aluminum to lauan substrate?

[vanwyk4257]

I'm using the 24" roll pvc-coated aluminum for a skin on my trailer over 1/4" lauan plywood. I want to minimize the amount of fasteners used and as such need to determine what adhesive to use.

I am seriously considering going ahead with either PL Premium or PL Advanced by Loctite. I tried searching but the search function doesn't seem to be functioning properly for me.

Any input on success with these or other adhesives for this specific application would be much appreciated.

Thanks!

[john]

PL premium dries a bit hard. Not sure about PL advance.

I used Henry's 663 on my first build around 7 or 8 years ago. It was an outdoor carpet glue that remained flexible after curing which is useful for the differing expansion rates of the materials you are using.

A couple of tips:

1) Scuff the back of the aluminum so as to give the glue something to grab.

2) Set the aluminum once. Pulling it off to reset it, or as in my case, to pull errant tree debris from behind the aluminum will compromise the process.

[madjack]

...minimal fastners??? I would skip the PL and goto something a bit more industrial and meant for the job at hand...such as SikaFlex 552 ...with what you are wanting to do, this is no place to skimp!!!!!!!!
madjack

[vanwyk4257]

PL premium dries a bit hard. Not sure about PL advance.

I used Henry's 663 on my first build around 7 or 8 years ago. It was an outdoor carpet glue that remained flexible after curing which is useful for the differing expansion rates of the materials you are using.

A couple of tips:

1) Scuff the back of the aluminum so as to give the glue something to grab.

2) Set the aluminum once. Pulling it off to reset it, or as in my case, to pull errant tree debris from behind the aluminum will compromise the process.

John,
Thanks for the input. The aluminum material I'm using is flashing and while I don't recall the exact thickness, I believe its .019, so I didn't think needing to have flexibility in the adhesive would be a concern as I wouldn't have expected much expansion and contraction from that thin material. It sounds like you do think some flexibility is important, is that based on using similar material? I really appreciate your thoughts.

[vanwyk4257]

...minimal fastners??? I would skip the PL and goto something a bit more industrial and meant for the job at hand...such as SikaFlex 552 ...with what you are wanting to do, this is no place to skimp!!!!!!!!
madjack

Yes, my plan was to either staple the top of one course before overlapping the next, or to just shoot one stainless steel screw with rubber washer under head (sourced all of it already from mcmaster carr) in each stud. I'd prefer to not have any visible fasteners on the sides of the trailer if possible but I also don't want to have any issues with proper adhesion and the fasteners would provide an element of redundancy.
I'm not even sure if I can source the SikeFlex 552 locally, and I only see a few places online that carry it.
I definitely don't want to skimp, but I don't want to overpay for an exotic adhesive if there's something a bit more conventional and cost-effective that will work.
I am definitely listening to your advice as you're obviously one of the resident experts here and I'm sure you know more about this than I probably ever will.

[vanwyk4257]

One other quick thought on fasteners. My father-in-law has a break for this material since he works with it regularly, I had thought about possibly creating an interlocking flange on the edge of each sheet and then installing a screw in such a way that the fasteners would be hidden. There would probably be a little bit of a visible lap on the seam, but at least no visible fasteners. Any thoughts on this?

[chartle]

One other quick thought on fasteners. My father-in-law has a break for this material since he works with it regularly, I had thought about possibly creating an interlocking flange on the edge of each sheet and then installing a screw in such a way that the fasteners would be hidden. There would probably be a little bit of a visible lap on the seam, but at least no visible fasteners. Any thoughts on this?

Something like the bottom figure in this? http://chestofbooks.com/home-improvemen ... Roofs.html



Also just because its thinner material I don't think you can assume that you won't have expansion issues. In fact I think you will have more. The thinner the material the more it can oil can.

Notice in both figures above that there are no fasteners in metal roofing to allow it to move.

[vanwyk4257]

Chartle,

Thanks for posting that picture and link, that's exactly what I had in mind except I wasn't going to use a cleat to attach the material, my thought was to screw right through the joint with sealant/adhesive behind it and then flip the sheet up and roll or use a rubber mallet to flatten the seam, thus covering all the fasteners and making the seam a little less obvious.

I'm not too concerned about a little oil canning as this is being built primarily for hunting and occasional camping, not for show.

[chartle]

Chartle,

Thanks for posting that picture and link, that's exactly what I had in mind except I wasn't going to use a cleat to attach the material, my thought was to screw right through the joint with sealant/adhesive behind it and then flip the sheet up and roll or use a rubber mallet to flatten the seam, thus covering all the fasteners and making the seam a little less obvious.

I'm not too concerned about a little oil canning as this is being built primarily for hunting and occasional camping, not for show.

The method above will give a much better look and seal.

If you are set doing it with the faster though the seam you should bend the top piece to a little over a 90 on the break, attach it and then roll or pound it down. The brake will give you much crisper bend and it will take much less time.

Also the expansion issue is just not for show. The movement of the metal could cause your joints to fail.

[vanwyk4257]

Thanks for the advise and the input chartle. My main issue is that my trailer side walls are approximately 78" tall and the material is 24" wide, so I'm going to have a few seams and having just an adhesive holding it in place doesn't give me a warm fuzzy feeling. I'll definitely work to minimize the number of fasteners and I do plan on putting roof edge molding on the trailer so that will help secure the perimeter more than anything. The finish on the aluminum is a very light khaki color so I'm hopeful that it won't absorb too much heat in the sunlight thus causing the oil canning you mentioned.

[bobhenry]

I used 24" aluminum flashing for the roof of "Barn to be wild" . I have had some issues with oil canning but HEY it's a barn. I overlapped 6" and used 3 runs of siding sealer with no leaks to date (18 months later). The only fastening is at the ends where I tucked it over the decking and trapped it under the trim. The top piece that capped off the top I did apply with a few rosettes and screws to secure the last run much like the cap row of shingles.

I really wish I had joined them with a double "J" fold with an upward fold on the bottom and a downward fold on the top to essentially "hook" them together then the sealer could have been applied in the fold line where they hooked together.



Here you can see the fold over and the screw that was added near the top of this starter "shingle"



Here is the rear fold over as you can see I got a little stingy with the material while guessing the length of the prow



here is a couple shots of the mild oil canning. This is where I think the double hook discussed above would have helped the looks a bit.

[chartle]

One other issue, if you do your installation method you need really flat headed screws.

If you press too hard or hammer on the seam over a screw head you will puncture the coil stock. The head will pop through, I have done it.

One other note, coil stock is very soft, metal wise, and doesn't hold fasteners very well. Any glue will probably be stronger than any way you could fasten it.

[vanwyk4257]

Thanks guys, great info and inputs on all counts.

I will definitely use flat head screws and I'll discuss the flanges with my father in law since he uses the break all the time with his jobs so he knows what we can and can't do with the material.

I will probably get a laminate roller and try to use that as much as possible to flatten the flange out. If I do need to do some pounding with a mallet I'll use a dead blow or rubber mallet against a block of soft wood to avoid damaging the aluminum.

[john]

It sounds like you do think some flexibility is important, is that based on using similar material? I really appreciate your thoughts.

Yes, except the material I used was not vinyl covered but bare aluminum flashing.

As for expansion, it is definitely a concern. For example; on one side tree debris fell between the camper and the aluminum as I was adhering it to the camper. I had to pull the aluminum off to get the helicopter seed and then re-adhere the aluminum. That run (I did 3 24" overlapping runs down the side) did not stick well and later puckered when in the sun but looked nice in the shade and winter.

The other runs have stuck nicely for 7 years and have an interesting "hammered" look due to the thin aluminum undulating over the Henry's below.

Having worked with Silkaflex since using the Henry's I would go with the Silkaflex. Mad Max is right. Very flexible and very sticky good stuff once cured. Bfore curing it runs easily, though, and might require placing the aluminum on your substrate while it lays flat rather than vertical.

[vanwyk4257]

Thanks for all the information guys, I appreciate it.