polyurethane has a bonding agent that does not melt into the plastic. It creates a coating around the plastic that is more susceptible to hook rash and scratches. Makes a nice clean finish that doesn't wrinkle paint...just doesn't hold up too well. Two part epoxy is the flagship finish coat. Try Devcon 30 Minute epoxy, EnviroTex Lite, BSI 30 Minute epoxy. There are others. EnviroTex has a slower working time than either of the two others...better if you are doing lots of lures. BassCat Dad does the best epoxy clear coat I've seen...if anybody knows how to use two part epoxy its him. His finishes are awesome.