I played around with copper plating last summer. Totally Muttcrew style with baking soda and an old 9v battery that had about 7v left in it. I mixed up the baking soda in distilled water – not sure whether that was necessary – connected copper wires to the battery and… dipped them in. After about 15 minutes the solution already had a clear blue color to it. Later I put a steel bolt on the cathode and… yes it did get a nice copper coating on the outside, but unfortunately rubbed off pretty quickly, so I may have to do some kind of finishing steps to get it to work properly.

One thing you can see here is that there seem to be tiny sparks going off in the gas that’s rising up from the solution. This was before I added the bolt.