you can get copper rods on Ebay real easy. It's a soft metal, easy to drill and easy to turn with a sharp chisel. It also conducts heat major, so it can get real hot to touch. I do not like it for pens because it gets dirty and oxidizes super fast. Lots of metals will oxidize and can make your fingers turn black over time, but none as bad as copper. Putting a finish on it is just a temporary fix and in the long run will come back to bite you. I think you can powder coat it, but the heat will change the nice bright color to be ugly and dark.