First I finished sanding and ScotchbriteĆng the ailerons ready for the finish prime, then I sanded the underside of wing for it's final prime as well. When that was done, one at a time I removed the screws holding the fuel tank to the wing, sanded and cleaned out the heads, smoothed out each wing dimple and replaced the screw. Next I scraped primer from the joins between all the wings skins and fuel tank to ensure any potential flex cracking in the paintwork occurs exactly along the skin join lines.