I said screw it and got some stuff to build an EDM machine for cathode removal, total so far is $60 for the actuator and maybe 40 for the electronic parts from Mouser. Most of the rest I have here. Case is an old battery charger, power for the EDM gap will be provided by a repurposed microwave transformer wound for 50v at around 10 amps, and the actuator moves the ram to set the machining gap during operation.

http://miniman82.4t.com/images/EDM/edmparts.jpg


Still needed are the tank and ram carriage, which I should be able to fab from aluminum. The pump and filter system should also be simple to make from an automotive fuel pump and a remote oil filter mount I have laying around, some fill and drain valves for the tank are hardware store items. Gonna give this thing a shot!