When I have done the bodywork on my Kr I've got the best results by mixing resin and micro ballons (no matter what epoxy-resin you use)at first, to a very dry mixture(no chance to squeeze on to the surface).Then add "household- alcohol"(in germany it is called Spititus-about 90-95% alcohol)to get a slurry mixture. It's easy to squeeze this micro slurry on to the surfaces.It takes a little longer to harden. Never take this mixture for structural bonding!! The adventure of the hardened mixture is a very good and smooth sanding condition and it doesn't give cracks later on!(it stays smooth and flexible all the time). Avoid taking vinyl-esther or polyester resin.This resin gets harder and harder by the time and you will get cracks later on.For small repairs on a finished surface you can use "top coat" (most boat manufacturer use "gel coat"in their molds before they continue with the glass layers ,or "top coat" when they working on a moldless item).Both products are based on polyesther and need a special primer to continue with epoxy resin! To get a good surface and stay light on a moldless wing ,the best way is, to start with a very good preparation of your foamshape.That causes in a minor amount of micro and resin for your lay up and finaly just as little micro for sanding the surface to its color condition. Once again,using colered "top coat" as described results in unwanted weight and cracks later on, due to it's uncontrolled thickness.
