I made a disappointing discovery today. Unfortunately when Sonex was forming the wing ribs, the process left a scratch in almost every flute on one side of the rib.
I tried using some 200 grit sand paper, but the scratches were so deep that it would have taken several minutes of intense sanding per scratch that way.
Fortunately, I found that a rotoray tool. and a scotch bright grinding pad made the process much quicker.
Removing scratches is one of my least favorite things to do....