This past weekend we worked on the curve part of the roof installing the first layer of 5mm marine plywood. Things were going great until the third piece, then CRACK! right in the middle of the third sheet as we were bending and clamping it in place. Bummer...I spent 2 hours monday scraping off sikaflex (I let it dry a bit overnight).
I am going to do some experiments with kerfing for the third sheet to see if I can get a safer bend. If that works I will kerf the second layer of 5mm and use Titebond 3 waterproof woodglue to bond it to the first layer. I would use epoxy but I don't think the pot life would be long enough for a 4'x8' sheet. Since we are also using sheet metal screws into the steel frame, I think the Titebond 3 will work ok.
The last couple of pictures are showing the start of the 1/16" aluminum siding install on the front pony wall of the camper. We are using Sikaflex 252 after a cleaner/primer of Sikaflex 205 and 210. The 210 is ungodly expensive and doesn't last long after opening...not real happy about that but what can you do? We are using 1"x1"x.5" rare earth magnets in some places to hold the aluminum to the steel frame (magnets have a 60 pound pull and yes I have a blood blister from letting two of them get too close to each other). We cut up 1/16" thick nylon tie wraps into little chunks and are using that embedded in the Sikaflex to keep the spacing between the steel and aluminum uniform. It is actually very quick to install a panel since there are no screws...much faster than the roof stuff.
