I found Raka went on so thin that I applied three quick fill coats before I started sanding. I was glad I did because I still went down to the glass and added two more fill coats with sanding in between. Spidey convinced me to use a fairing board with 80 grit and that is indeed the way to get a smooooth surface. I concluded the quality of the finished surface depends on the effort applied. I still like to use a scraper on the runs and bumps before fairing.