Glue or float aluminum roofing and sideing

[backstrap bandit]

Do you prefer glueing aluminum on screwing it on or float it and let trim hold it on

[George Taylor]

I screwed our aluminum on. The metal expands in the summer heat and I did not think that the glue would hold to the smooth metal when it moves. Have not had any problems.

[backstrap bandit]

I have the same concerns about the glue not holding but also have a concern about puting a bunch of screw holes in it also thought that when I put the trim on with screws that would hold it around the edges because I really don't want to put screws in the field just wondering how everyone else is doing it and if they have had any problems leaks ect.

[Irmo Atomics]

I attached my aluminum with stainless pin nails and then put the trim with screws over that. I put a dab of sealant (parbond) in each screw hole before I put the screw in. I don't have any screws in the field, so during the summer - especially in the sun - I get some oil canning. It lays back down when the day cools off.

[backstrap bandit]

I would think if there was a way to put an oblong hole where you wanted a screw that would take care of the oil canning slowing the metal to expand and contract at will. You know like vinyl siding has or same principle when attaching table tops I do aloud of wood working and cabinets used to build houses and this is use y'all's how it's done

[drgrumpus]

This is such a great topic. Lots of good info from other builders. I am going to put 1/16(.063) aluminum diamond plate on the front (modified Grumman II profile) as a stone guard over my two layers of 1/8 Baltic birch. A local sheet metal shop can roll form it to my template. That will save me the hassle of bending it myself.

I plan to put two coats of CPES on the BB, then attach the Al with screws through enlarged holes. I'll use SS washers under the screw heads and only snug them, which should allow the Al to expand/contract. I'll put silicone caulk under the edges of the plate. It should be flexible enough to allow for expansion. I will leave a few gaps in the caulk at the bottom to help drain away any water that does get in.

Comments?

[Shadow Catcher]

I would use VHB tape. The semi trailers that you see with no rivets likely use it. Check the 3M web site.

[drgrumpus]

VHB tape, eh? I checked it out, and 3M lists many types/thicknesses. What would work best (Bare Al on wood)? Also, will the VHB provide a water seal?

Thanks for the input.

[aggie79]

VHB tape will work well but it is very unforgiving. You have one chance to make a perfect fit. Once adhered, even initially, you won't have a chance to reposition your aluminum. The tape is crazy expensive too.

[Prototear]

I too have been considering VHB tape for putting the skin on my teardrop. Fred of Alaska Teardrop recommends a specific type and shows a pretty reasonable price viewtopic.php?f=2&t=56935&p=1030950&hilit=4919f#p1030950, but I haven't been able to find for less than about 2 or 2.5X that amount so have been looking at alternatives. In searching, I have found another brand (not 3M) of Ultra High Bond tape here http://www.findtape.com/product462/JVCC-DC-UHB25FA-Ultra-High-Bond-Double-Coated-Foamed-Acrylic-Tape.aspx?idx=0&tid=0 that I'm considering.

Since my frame has 1" square tube for the sides, I would also rivet it as Fred describes in Stacy's build, with closed blind rivets. To keep the aluminum skin from contacting the tape before I am absolutely ready, I got some clecos, including some long ones http://mrotools.com/kwnl-fw-3-16-long-kwnl-0-1-grip-wing-nut-Cleco-Fasteners.aspx, so I can dry-fit it and even trim it if I want, before attaching it.

Meanwhile, I am thinking through this as I finalize my approach so I can be more certain when the time comes so I don't make any expensive mistakes.

[AlgoDan]

I floated my roof/siding, the trim and windows hold everything fine. I used an exterior silicone adhesive to all outer edges prior to applying the panels. Has held up good.

[alaska teardrop]

I think you've gotten some good advice & if you search this site, you'll find loads of information on this subject. I use VHB tape to hold metal to metal, but wouldn't recommend it for metal to wood where strength is needed. However, with research you may find a 3M tape with two different sides meant for the application.

Steve wrote:

I too have been considering VHB tape for putting the skin on my teardrop. Fred of Alaska Teardrop recommends a specific type and shows a pretty reasonable price viewtopic.php?f=2&t=56935&p=1030950&hilit=4919f#p1030950, but I haven't been able to find for less than about 2 or 2.5X that amount so have been looking at alternatives.

Steve, my distributor for 3M 4919F VHB tape:

L&D Adhesives, Inc.

5180 West River Dr. N.E.

Comstock Park. Mi. 49321

616 785-1459

Possibly they could mail it or put you on to a local distributor.

Fred

[halfdome, Danny]

As I've posted before in similar threads, I spray on 3 coats of Wilsonart contact cement on the plywood and the aluminum.
Haven't had one problem with the aluminum/plywood bond on the teardrops I've built.
I take my dual action sander, with 80 grit sandpaper, and scuff up the back side of the aluminum to give it "Tooth" for the bond to work.
After sanding, I clean the aluminum with lacquer thinner.
I use VHB tape on any lap seam, cleaned first with rubbing alcohol.
The choice to glue or float is a personal choice as both methods work. Danny

[Prototear]

Thank you very much Fred. When I get closer to having to order it I'll give them a call if I haven't found it locally by then.

[junocustomteardrops]

We always float our sides and roof (held by the lip of the trim) and found that this works the best for a few reasons.. The seamless look the aluminum gives w/o screw holes into it. Floating does not restrict the wood's "breathing room" and its being able to expand/contract with the changing air moisture and temp. How well they (Sides/roof) stay in place via the side exterior trim. And maybe most importantly, the fact that this method is not permanent, and allows for multiple attempts to adjust, and fine tune in some areas. While screws give you re-do's, they leave holes, and most glues think that re-do's should not exist, we found it better all around to float our aluminum..

We have experimented and made mistakes in both gluing/screwing and floating our sides in the past. But I think it comes down to a preference in the end, and if you think your sideing goals are being met, or if they can be improved.