Using the Eco-Fill to prime the wingtips and window frame as they are raw fiberglass and need to have some UV protection. I sprayed on two coats as per Stewart system info (two coats by Stewart system standards is four cross coats). I think I should have brush coated on the first coat then the two sprayed coats. The wing tips that come with the kit are crap as there are pin holes galore. I had a chance to buy a set at the Arlington fly-in in 2007 right next to me at the Bushcaddy display off of a super cub kit that fit the wing perfectly and they were primed and ready for paint.