We would all like to 3D print in metal, but for now, the equipment to do that is out of reach for most of us. Instead of dealing with powder printers or metal-bearing polymers, [Robert] has a simple solution. Using a process known as mechanical plating or peen plating, he deposits a layer of copper on a PLA print. The results look good, as you can see in the video below.
This isn’t electroplating, although the result is similar. With electroplating, you have to make the 3D part conductive. You also have to deal with wet chemistry and fumes. This process uses a rock tumbler, copper powder, and small ball bearings.