[Tyler] has had his electrochemical machining hack up for a while now. His final version uses a pump to move electrolyte out through the etching head and onto the workpiece. This keeps fresh electrolyte in the etching region and clears out the insoluble material. We see how this could be attached to a CNC system and used to etch PCBs without the use of a special inkjet printer, toner transfer, or laser etching machine.

[thanks Ian]