Glue? How to attach aluminum skins....

[geocachenut]

Working with a supplier for all of my teardrop parts....I am curious about attaching the aluminum skins (using .063 to the sides, and .040 for the top) to the 3/4" Baltic Birch sides. Supplier says to let them "float" with just the aluminum extruded trim holding them on, but I've seen some say that you should glue them down. Now, I am really concerned about the difference in which the aluminum will expand/contract vs. the 3/4" birch......what do you guys think? I plan to post some pics of the progress so far soon!

[aggie79]

This question will get you almost as many different answers as asking what your favorite teardrop design is.

I'm in the "float" camp but used sealant/adhesive around the perimeter and at all openings along with the trim to keep the aluminum attached. The exterior trim was bedded in sealant too. All screw and fastener holes were pre-drilled, sealant was injected into the holes, and then the screws/fasteners were put in place. Here's a few photos:











There is some minor oil-canning in the aluminum in the extreme heat of the summer, but I feel that is better than having the aluminum expand and try to separate from being directly bonded to the plywood.

Take care,
Tom

[Steve Frederick]

I've never done sides, but for roof skins,(I've done two) I used outdoor carpet adhesive. I spread it with a notched trowel. Working time is short, so plan the job. (Do a dry run)
They say that glue will eventually release it's bond, so plan on trim and other items to really hold the skin.

[Robbie]

I did my skins just like Tom did. I used that black polyurethane sealant around the entire perimeter and any openings and stapled the sides and roof around the edges, also like Tom. Then just covered it with silver roofing sealant and edge trims. Around the doors and rear opening though I folded the aluminum in so it covered the end grain of the wood and then stapled on that surface instead of the outside face.

[halfdome, Danny]

Why are you using .063 for the sides? Seems a little thick and unnecessary.
I use .040 everywhere and it's thick enough. All that is needed is .032 unless the size you need comes thicker.
I used contact cement for the builds I've done with absolutely no problems.
My friend Ed E. used water based contact cement on his 44 teardrops with no problems.
This ripping of 3/4" plywood because someone used contact cement is (in my opinion) a theory without proof.
Do as you wish, either method will work just fine.
Danny

[webbaldo]

Toms right, everyone has their own ideas about this.

After seeing an Ice cream van here in the UK in the heat and the alu sides expanded out, I thought putting glue everywhere would result in the plywood being ripped off with expansion and contraction.

I used 0.9mm alu, not sure what that is in imperial

I floated them *but* put 2 beads of adhesive near all perimeter edges about 1inch in from the edge, and then 3 inches between glue lines.

This keeps everything in place till you get time to do your trim. A few staples with an air nailer round the edges (hidden by trim) helped keep everything in place until it set. (These were then covered in sealant before trim to keep water tight)

Here in the UK after some tests I found this is by far the best adhesive, not cheap at £6 a tube but is rock solid and bonds practically anything, and is waterproof

[AlgoDan]

Will be applying the skins in the couple of weeks, have read many posts on the subject. I believe the float works for me and will basically be doing as Tom has done..He has done a excellent job as one can see....

[AlgoDan]

Hey Tom, Nice build and application of your skins. I plan on doing what you have done, clean and sealed from the elements. Good job!

This question will get you almost as many different answers as asking what your favorite teardrop design is.

I'm in the "float" camp but used sealant/adhesive around the perimeter and at all openings along with the trim to keep the aluminum attached. The exterior trim was bedded in sealant too. All screw and fastener holes were pre-drilled, sealant was injected into the holes, and then the screws/fasteners were put in place. Here's a few photos:











There is some minor oil-canning in the aluminum in the extreme heat of the summer, but I feel that is better than having the aluminum expand and try to separate from being directly bonded to the plywood.

Take care,
Tom

[Irving]

Anyone ever used 24" wide aluminum, like this product, and layered it on the roof?

http://www.hardwareandtools.com/Billy-Penn-6559S-Aluminum-Roll-24-Inch-By-50-Foot-4462842.html#description

[halfdome, Danny]

Attaching aluminum with contact cement also acts as a wood sealant.
Camp Inn floats their aluminum but sprays a sealant on the raw plywood first.
Something you might consider before covering up all that raw plywood with aluminum.
Dry rot is not a good thing.
Someone shared this photo with me of a Camp Inn on their rotisserie being sealed.

Danny

[aggie79]

Attaching aluminum with contact cement also acts as a wood sealant.
Camp Inn floats their aluminum but sprays a sealant on the raw plywood first.
Something you might consider before covering up all that raw plywood with aluminum.
Dry rot is not a good thing.
Someone shared this photo with me of a Camp Inn on their rotisserie being sealed.

Danny

Danny,

You bring up a very good point. I think either the direct glue or floating aluminum are equally good methods, but if you float your aluminum you'll need to seal your plywood first. I used epoxy, which is overkill, but any sealer should work.

BTW, your quality of work and craftsmanship is something I aspire to achieve but probably will never come close.

Take care,
Tom

[halfdome, Danny]

Thanks Tom for your kind words, it means a lot to me since working with wood (cabinetmaker) has been my life long vocation.

I also put sealant at the roof edge where the top and bottom aluminum meet and then on both sides of the RV insert molding and each SS screw.
I put 3/4" aluminum channel with sealant on the road edge of the walls to keep moisture at bay.
Danny

[len19070]

I've never done sides, but for roof skins,(I've done two) I used outdoor carpet adhesive. I spread it with a notched trowel. Working time is short, so plan the job. (Do a dry run)
They say that glue will eventually release it's bond, so plan on trim and other items to really hold the skin.

I'm with Steve on this.

I used to put a few gobs of cheap silicone down just to hold it in place (Knowing that eventually the silicone would break its bond) But now use the carpet glue applied just like Steve does.

This glue can be rolled as well though and I have used it several times on EPDM Rubber roofs.

BTW, just an opinion. Silicone makes a better glue than a sealant.

Happy Trails

Len