Posted by David Sherman on Tuesday, May 14, 2002 at 8:35PM :
In Reply to: So Has Anyone Tried Electrolysis Lately?? posted by James Fuller-Devine on Tuesday, May 14, 2002 at 7:38PM :
On the plus side, I used it very successfully to derust a bunch of tooling for an old lathe I bought. After 10 hrs or so electrolyzing in the bucket, I did a quick cleanup on the wire wheel and oiling, they had a nice, almost blued finish. No flash rust. Of course all the rust pits were still there. The only item that had any original bluing on it was a boring bar holder and the electrolytic process removed the rust from the rusty end without hurting the bluing on the good part. An acid pickle would have stripped it all to bare, etched steel.
On the other hand, I tried it on some ancient iron nautical artifact we found out on the coast a couple years ago, and it pretty much ruined it. The artifact looked like gray iron with lots of rust over it embedded in rusty sand, but it turned out the outside 1/8" or so of the iron part, with all its fine details, had really turned into magnetic iron oxide over the years of being buried in the sand. I should have noticed when I couldn't solder a wire onto it, but I went ahead and scraped down one corner to bare iron and soldered onto it. After a couple hours of electrolyzing, the black oxide layer had all crumbled, taking with it all the interesting parts of whatever it had been. I stopped then, not wanting to ruin what was left by stripping it down to a thin rounded iron core.
The main limitation of the process for practical purposes is that it's hard to make a decent electrical contact to a large number of small parts, as when cleaning up rusty bolts and nuts and small hardware. I made a small bag out of aluminum window screen and put everything in it. This works okay, but very slowly since the screen is closer to the other electrode than the parts are and most of the "action" happens on the screen rather than on the parts. Even so, a day in the bucket, shaking the bag of small parts once in a while, seems to do the job.