One of the side jobs is covering the hole I drilled when I was building a 7A. As the steps will not be installed in the TW version, I have this hole to cover / slash fill. My plan is to make a small backing plate to rivet underneath the fuselage skin. This will leave a 3/32" circular divet in the skin. There are two ways to handle that divet. Cut a 1 1/2" plug out of 3/32" material and rivet it in the divet to the backing plate or fill the divet with microballons and sand it smooth.
My first thought was to cut a plug out of 3/32" and rivet it to the back plate. That would reduce the microballon fill to just the edges. After thinking about it I decided to just fill it in with microballons and sand it smooth. There is a compound curve and I will not be able to get the exact curve on the plug.
I drew a template on the fuselage to determine the size of the backing plate. I transferred that to a piece of paper and marked / cut the rivet holes of the existing rivet line. If you look closely at picture one you may see red dots. Those are the proposed additional AN426-3-3.5 rivet locations. All-in-all there will be seven additional rivets holding the backing plate. When I am completing the fiberglass on the wing tips I will finish this project.
