A guy has asked me to powdercoat some aluminum castings he has that he uses to make sand molds. He wants them coated to help the sand not stick to the aluminum when he makes his molds. He used some JB Epoxy Putty to fill some holes on the ends. JB says this will withstand the curing temps, but it is not electricaly conductive. I have out gassed the parts, and thats what the black specs are from. Has anyone tried to powdercoat over epoxy like this?