RE: Wood Filler
I've used the epoxy with sanding dust technique Carl described with good results. Just remember that most epoxies will break down from UV light over time. So if the filler is going to be exposed to UV, say on the outside of the boat, through a window, etc., you probably want to cover it with something--- varnish or whatever you use as your natural satin or bright finish--- to eliminate the risk of having the epoxy break down from UV over time. Most natural finishes these days have a degree of UV resistance.