Deburred the flap skin and ribs, dimpled the top and bottom surface of the skin using the 5/32 dimple dies made by my friend Dusan (many thanks yet again), then coated all mating surfaces with cortec corrosion protection. Once this was dry I re-assembled the right flap and riveted the entire assemby. The dimple die works really well, only problem is its very tedious doing this using a had riveter.