expansion and contraction

[gene so]

Hello,

I am seeing aluminum sheeted trailers out there and suddenly this thought has arisen' How do those aluminum sheeting sides stay straight in the expansion and contraction which must take place in these trailers due to temperature, and sun exposure?

I am planning to build a custom framed trailer with sides made from smaller tubing and a sandwhich style of fabrication. Since the sides will be welded to the frame and the steel tubing connecting the sides will become the roof structure, logically this will become a very rigid situation. If you attach an aluminum skin via riveting to this tubular frame and it goes through significant changes in temperature ( 40 degrees in noon to midnight exposures here at 6,5000 in northern New Mexico) something has got to give! What shapes, sizes and techniques can be utilized to keep the external sheeting ( on a 9 foot trailer) straight and firm and not leaking ?

Thanks in advance,

Gene so

[doug hodder]

It's going to be difficult to completely stop the "oil canning" effect from heat on the aluminum sides. Look at any of the large 40' semi containers. They still show a bit of it. I'd put a strip of 3M VHB foam tape on the steel prior to installing the aluminum skin and rivet it through that. A huck rivet would be a better type as opposed to a pop type, as the latter has a hole. The tape cuts the galvanic action between the aluminum and steel and will help to stick it all down. Most of the large truck cabs are built using the tape and it's a common practice in the sign industry. I don't think the rippling "oil can" effect is going to be real issue however, as a tear doesn't use huge sheets of material.

My canned ham, the Nomad will pop occasionally in hot temps....and I've got large areas unattached, mostly all floated.

Doug

[Shadow Catcher]

If you are doing a metal to dissimilar metal, aluminum to steel you do not want any fasteners connecting them or you will have galvanic corrosion!

The semi trailers that you see running down the road with out external fasteners are for the most part held on with 3M VHB tape. 3M has lots of information including side design with a floating bottom to allow expansion and contraction. There are no fasteners used as they defeat the purpose of being able to move.
VHB tape hold my Kedar/awning rail, solar panel mounts, the mounts for the air compressor and air tank (I did not want to drill holes in the sides of the tongue box).

[corncountry]

Hello,

I am seeing aluminum sheeted trailers out there and suddenly this thought has arisen' How do those aluminum sheeting sides stay straight in the expansion and contraction which must take place in these trailers due to temperature, and sun exposure?

I am planning to build a custom framed trailer with sides made from smaller tubing and a sandwhich style of fabrication. Since the sides will be welded to the frame and the steel tubing connecting the sides will become the roof structure, logically this will become a very rigid situation. If you attach an aluminum skin via riveting to this tubular frame and it goes through significant changes in temperature ( 40 degrees in noon to midnight exposures here at 6,5000 in northern New Mexico) something has got to give! What shapes, sizes and techniques can be utilized to keep the external sheeting ( on a 9 foot trailer) straight and firm and not leaking ?

Thanks in advance,

Gene so

Hello Gene
My second tear was built using .040 aluminum over 16 ga. steel tubing framework. I used 3M-VHB tape to fasten the sides and top. The only solid fasteners on the sides are stainless screws for the hinges. There is some give in the tape so the sides can move around. Very little rippling in mine, this is Iowa and midwest weather I am talking about, although we had a lot of 100 deg. + days this summer. There are a few build pictures in my album.

Jim