I started out the weekend taking the flaps apart just to clean them up abit. There really is a lot of drilling on these and the mettal shavings get between layers and everywhere. Once I got them kind of cleaned up I countersunk the spar where the flap hinge attaches. The directions indicate sjuch so you don't have to dimple the soft hingle aluminum which provides extra strength. After the one side of the spar was countersunk, I assembled the flaps and drilled the skins.
After the skins are drilled, the 3-4 hours of deburring and dimpling takes place. Every little step takes much longer than you expect. Don't forget the soldering iron on the skins to remove to top layer of plastic.. However, after a days work, I have both flaps at the same stage and ready for the scuffing, alumiprep and alodine treatment.