Bonding aluminium to galvanized frame

[madjack]

Billy, you may also want to check out 1 and 2-part urethane adhesives...this is the stuff which is used to bond auto body skins to the frame in OEM vehicle manufacturing...SikaFlex is one brand and most major adhesive manufacturers make a version...should be available thru auto body repair shops and their suppliers..........
madjack
http://www.sikaindustry.com/ind/ipd-tra ... oem-tt.htm

[kennyrayandersen]

Depending on the thickness and properties, the tape may act to insulate the skin/frame against galvanic corrosion. Still, I'm not sure it's that big of deal -- the Low-cost cars are all built using aluminum skins on steel frame and don't seem to have too much trouble. If you don't use fasteners and a little thicker tape it will probably stick pretty good and also allow for a little bit of movement for the difference in the coefficients of thermal expansion of the two materials. Since your strength is coming from the steel frame, .025 or .04 would be plenty thick -- .040 being a little less prone to dinging. .040 is getting a little easier to find. I recommend 5052 alloy (T-32 or T-34 -- T-32 being a little easier to work with) as it can be welded, has decent strength properties and is easily formable.

[mechmagcn]

I'm with Madjack on this one. I used auto body panel adhesive to install the skins on my TD. .040 over 1"X1" steel framing. No ripples in the skin even when sitting out in 100 degree weather. The adhesive will seal any contact between the dissimilar metals, so there shouldn't be a problem there either.

[switterstx]

Ok, I'm liking this idea more and more. Jeff, how much sikaflex did you use for yours? If I remember yours is about the same size as what I'm building. How did you apply it? Just a bead down the tubing is what I'm figuring. Did you use it for the roof also? If I remember you used plywood on the roof, then a vinyl membrane. I'm going to put aluminum all around.

THanks MJ and others for the suggestions, this is helping me out too.