On my first hull I sanded a bit to much into the fiberglass and when I varnished the hull I could see a lot of the fiberglass weave. It was a little more than I could live with. I removed the the varnish and applied one more coat of epoxy and was very careful not to sand to deeply into the fiberglass. When I varnished the hull it turned out much more to my liking. Sanding was the worst part of the building proccess for me. Now I wish I was a little more picky. Oh well, I'll just do a little better job on the next one. Good luck.