Bit late for a reply, but might help someone. To make 'crinkle' sets by hand you just need a hammer, adjustable spanner and a big screwdriver. Hammer the sides of the tray flat where you want to bend it, wind down your spanner so it just fits over there edge of the tray and then twist the spanner using your big screwdriver (most adjustable spanners have a hole in the other end that you can put the screwdriver through to held twist it). If you do this on each side of the tray in the same place, moving along the edge as you go and twisting in opposite directions each time, eventually it will start to bend. Looks really nice when its down and saves a fortune on internal bends.