resin or hard foam baits its fine. . we mix our 4.1 in shooter cups from the dollar store. on all metals, plastics its superb with gloss finish. on metals we use a lo-bake oven. we have blades 20 years old and there still slik shiny.. it all seems to go back to your adhesion issues. normally we use lacquer based paints,and any 4.1 clearon the above mentioned works. woods are another story line. good luck i hope i helped someone out.