CrustyCrayon

I am a student at the Art Institute of Pittsburgh, and I am currently making some soft plastic lure molds. (no seriously the cnc machine is running right beside me.) I know I can melt down some old lures to use, and I have seen the tubs of plastic online, but what are the baits made out of. I konw every company and style is different, but they are still simular. So does any one know what it is called (ie. chemical name, like ABS plastics) , and where can I get the best deals on it?