The fuel tank, non working, was bent up around a scrap wood former. The measurements were again supplied by my man with the tape, Iain, along with good side view photo's which showed the radius of each corner ! Although the base of the tank was wider than the top, all corners were the same radius. The original idea was to bend the alloy around the former then remove it which left the question, how to fix it all together. The obvious solution, apart from alloy welding, was to screw the panels to the wood which would be left in place hidden from sight.
Odd bits of wood were dug out, cut to size, and screwed together after first using the ends to mark out and cut the alloy outer plates. These were bolted to the wood with countersunk BA bolts, the heads blended in with filler. The main panel was cut to size and after carefully lining up, was screwed to the underside of the former. Then it was bent around one face at a time, securing with screws before moving on to the next, and finishing on the underside. Where else. All the screw holes were countersunk, the screws again being blended in with filler.
The filler neck was a short piece of alloy bar, screwed into place, and finished off with a cap from an oil can. Rubber edge trim was fitted after painting.