I used to use the gap seal tape, but I got tired of the $3 per foot price and not being able to find it. For the last year I have been buying the overhead projector clear sheets from an office suppy store, giving the edge I want to glue a touch with some 180 grit sandpaper and using medium CA to secure it to the wing. If you run the bead of glue on the wing, place the strip down and rub it with a paper towel till it kicks, it will come out very nice. Been running them on my 426 planes for over a year with no failures yet!