Stephen,
I have used the electrolysis method for rust removal and it works quite well. Specifically, I used it to clean down to bare metal a large, ornate cast-iron flywheel that was heavily rusted, and the result looked like it had just come from the foundry. I used a $5.00 plastic wading pool for the tank, and the iron rebar electrodes were simply hung from the edge with the connecting wires - the suspension method shown in the video is more elaborate than necessary, but perhaps better lends itself to repeated use. As I recall, the sodium carbonate (washing soda) I used was sold under the Arm & Hammer label in grocery stores. I rested the heavy part to be cleaned on a couple of bricks.
But while this is a good method of rust removal, the problem at hand, as I recall from seeing the boxcar last fall, appears to be more a situation of paint removal. If the paint in question was on top of rust, electrolysis might encourage it to fall off, but in that case it probably wouldn't be adhering too well anyway.
If you decide to experiment with electrolysis, an important safety concern is that the process produces hydrogen gas, so setting it up indoors, as the video appears to show, is definitely not a good idea. If you leave the process running outdoors, you may want to suspend some sort of roof over the tank, as rain will dilute the sodium carbonate solution and reduce its effectiveness. In my experience, larger items require more time than the small nuts and bolts shown in the video - my flywheel took three or four days to come clean. Additional electrodes might have helped this along.
All in all, sandblasting is much, much quicker if the facilities are available, and will easily deal with paint just as well as rust. A cabinet is not necessarily required except for the smallest parts, as plywood or similar material can easily be set up as a sort of work enclosure to direct the nozzle toward, which will help capture most of the sand for re-use.
Jon Chase
