QUOTE(stownsen914 @ Sep 13 2015, 08:17 PM)
Resin doesn't tend to sand as easily as gelcoat in my experience. For the fg work I've done, I try to minimize the sanding of resin for this reason. When you do your repair, put some tape on the shiny/outside of your work to keep excess resin from leaky through and running all over the place - it will save you work later. You can also remove excess with acetone or similar before it sets completely. To fix the cracks and crevices on the shiny side of the fg, just use your favorite autobody filler. It will sand a lot easier than resin.
Scott
Ah so a little bondo on the front side. Fiberglass/resin on the back then?