The aluminium sheet is 1.5mm thick, too thick for long cuts cut with tinsnips. 1mm would have been easier to handle but I worried it would sag between the frames, especially if/when someone leans on it. Fortunately I have an old B&D jig saw so I fitted a metal cutting blade to that to cut out the roof panel. Then drew round it and cut out the second one.
After filing and de-burring the edges I drilled and countersunk fixing holes all round. Note the back yard bench made out of pallets, the aluminium sheets are too big for my shed.
The outboard edge of the roof will overhang the cockpit side by about 20mm and have a(roughly) 10mm wide downturned edge to it to make sure rainwater drips off on to the deck rather than running down the side windows. Here the sheet is sandwiched between a couple of recycled 4x2s. The far end of the timber has been cut to an angle matching the shape of the roof. The hide hammer was rescued from my father-in-law’s garage many years ago. It had been badly mistreated but I fettled up one end and replaced the handle and it’s ideal for a bit of metal bashing.
The fore and aft edges will also be turned down, but not until the sheet is secured to the frame to hold its curved shape. If I turn down the edges first the sheet will be very hard to curved nicely. I’m going to need something solid to hold under the edge while I bend it down. Time to rummage under the bench…