Russel I think you are right on the covering, but every arf I ever owned I always fire up the socked iron and the edge sealing iron and go over every sq inch so maybe thats why I have such good luck in the wrinkle/seam dept. I also use a couple of sticks(6') of triangle stock on every arf, Fire wall, bulk heads get most of the triangle and I usually glass in the landing gear bay, seal the hinges, and use thin ca with a long tip on about every joint I can reach (neatly I might add) don't like glue drips or slop.............sure an extra 3 hours on a 20 hour arf is a slight pain, buts it's worth every min not having the trouble down the road.[8D]