I bought some of this stuff recently and so far it seems to work very well! Most of the things I have used it on are not heavily rusted, though. Light rust takes a couple of hours, heavier rust takes overnight. I don't know how practical it would be for large parts, but for smaller ones it does a good job.
I also tried it on a small area on the door on my truck. I soaked a cottonball in the stuff then put it on the rusted area and covered it with saran wrap and taped it to the door, a couple of hours later and no rust. It affected the paint a little, but I just waxed the area where the stuff contacted the paint, and it looked normal(BUT, my paint is original and not in GREAT shape-so be careful if you use it on your truck). The evapo rust is also reuseable, non toxic and environmentally friendly(according to the Mnfgr.)
http://www.orisonmarketing.com/corro...vapo-rust.html
I've got pics at home of an old C-clamp I tested this stuff on and I will try and remember to post them later.
Mike