Started de-burring all the holes in the skeleton. This is, pretty much, the most boring part of this project, but, absolutely necessary. After drilling, the holes have sharp edges that must be smoothed (Picture how easy aluminum foil is to rip…now imagine there’s an edge around a hole that thin. Cracks are most likely to start in places like this and then spread into the thicker metal). I use a de-burring tool in a cordless drill at a slow speed. A de-burring bit looks a little like a countersink. Some of tight corners required I remove the bit from the drill and de-burr by hand. I got all the ribs, reinforcement bars and angles, and the rear spars done.