I should have mentioned that this trick is very easy to do with ARF's Get a roll of transparent Ulracoat, cut a strip approx 2" wide and as long as the control surface you want to seal ie. aileron. Take Acetone and wipe clean the complete area so no oil or fingerprint residue is present. Now lay the piece of Ultra coat and seal it the same way as I described above.

You'll be amazed at the performance increase your controls have when there sealed.