Bonding aluminum to plywood

[scroadload]

I'm planning to build a TD and wish to clad the roof and sides with anodized aluminum but I don't want use any fasteners or moldings along the roof-wall joint. I'm considering using Sikaflex 292 or 3M 5200, does anyone have any experience with this method.
Do you use the adhesive at the edges to allow for expansion? if so how much, 3 or 4 inches?
Thanks in advance for any help.
John

[George Taylor]

All I did on ours was use some aluminum gutter/trim caulking around the edges, openings or holes and used some aluminum strips with counter sunk holes for some screws. The aluminum does expand some but the caulking realy sticks. I got the stuff at Lowe's and it comes in clear and grey/aluminum.

[aggie79]

I'm using 3m 4200 as a sealant between the aluminum and plywood and between the roof edge molding and roof and sidewall aluminum.



I did use staples at the edges and screws to fasten the roof edge molding though.

I think either of what you suggested would work. The aluminum sheeting wouldn't be to hard to do. You'd probably want to do the walls before you stood them up. On the roof, you could use load binders. The trickest part will be how to hold the roof edge molding in place.

[hoofhearted]

I'm thinking about using aluminum to skin my project teardrop. Can you use a carbide router bit to cut out the aluminum around the door/window openings? Has anyone used sheet stainless to skin their tear or is the stuff too difficult to work with?

[BrwBier]

:) I'm planning to build a TD and wish to clad the roof and sides with anodized aluminum but I don't want use any fasteners or moldings along the roof-wall joint. I'm considering using Sikaflex 292 or 3M 5200, does anyone have any experience with this method.
Do you use the adhesive at the edges to allow for expansion? if so how much, 3 or 4 inches?
Thanks in advance for any help.
John

I'm not saying it can't be done with out any moldings but cutting the two materials (roof and wall) with hand tools to get a perfect joint will be hard. Even the smallest imperfection in one cut or the other will stand out (mostly to you) when assembled. A water tight joint will also be hard and very important, especially after all the work put into building your dream.
Brwbier

[azmotoman]

I work on aircraft and the 3M products work really well for us. Adheres carpeting, laminate, vinyl and aluminum. Read the label for specific information about your particular requirements, apply AS INSTRUCTED and enjoy.

[madjack]

I'm thinking about using aluminum to skin my project teardrop. Can you use a carbide router bit to cut out the aluminum around the door/window openings? Has anyone used sheet stainless to skin their tear or is the stuff too difficult to work with?

...yes you can but there a couple of problems to be aware of.........
1) you may havvta slow your router down...if you don't have a variable speed router, you can get a speed control switch at Harbor Freight for under 20 bux
2) due to speed of router or sharpeness of bit, you can have problems "slagging" the AL as it cuts...both of these problems can be helped by getting a "shear" angle bit... http://www.rockler.com/product.cfm?page ... uter%20bit

madjack

[madjack]

:) I'm planning to build a TD and wish to clad the roof and sides with anodized aluminum but I don't want use any fasteners or moldings along the roof-wall joint. I'm considering using Sikaflex 292 or 3M 5200, does anyone have any experience with this method.
Do you use the adhesive at the edges to allow for expansion? if so how much, 3 or 4 inches?
Thanks in advance for any help.
John

John, how do you plan on sealing that edge...I just don't believe any type of "butt" joint is gonna work over the long term so some sort of molding will be required...while the 292 or 5200 will work, I don't use anything to hold the AL to the ply, allowing it to float. I use a couple of air driven staples to hold the top in place and then rely on the trim/moldings/light/vents/fenders/hinges/etc to hold the AL in place...I use a combination of butyl putty tape or caulk to seal all of those things depending on the specific application.............
madjack

[angib]

If you are determined to skin with aluminium but without corner trim, sealing the exposed corner becomes a real problem. A particular concern is that if the corner joint starts to leak, you may not know it until it's way too late to save the plywood underneath.

One thought that came to me was whether it might be a good idea to lay an aluminium angle inside the corner instead of outside. You would need to use a router to make a recess for the angle to sink into, to get the outer skin flush, without a bump at the corner.

I don't think bonding the aluminium skin to the aluminium angle is necessarily that much easier to do, but it gives you a 1" (or whatever) width of joint in which to make an effective seal. I suspect some of that expensive 3M VHB tape would make a really good joint between the two.

I can't say this is a good suggestion - I'm just thinking out loud.