Originally Posted by
capnjonny
I just got back from 15 days in the Nevada Desert at this year's Burning Man. Actually I got back on Tuesday Sept. 2 but I picked up a nice going home present, Covid, on the way back so have been hiding out in my fortress of solitude trying not to infect my wife and kids. Finally , yesterday, I went out to the shop to work on an Indian Scout bicycle the Bike Exchange received as a donation. I wanted to de rust some chrome bits so I reached for my wide mouth container of vinegar to soak them in and here's what I saw.
I had forgotten I had the bottom bracket cups, beatrings and spindle in the sause and had left it there for over 3 weeks.
Disgusting is too mild a term for what I found. When I had put the parts in the vinegar It was fairly new and clear . when I pulled the parts out the nuts on the spindle had completely disintegrated and the spindle -- just look for yourself.
Surprisingly, the inside of the cups did not seem affected but the caged bearings were black and crusty.
Just goes to show, white vinegar is definately an acid. I still can't figure out what caused the foamimg.
Any chemists want to chime in there?
Rust…iron oxide…reacts with the vinegar, acetic acid, to form iron acetate. The acetic acid reacts with iron…not the oxide…to form iron acetate as well. However, a byproduct of the reaction is hydrogen. Since you left it in the solution for so long, you are much more likely to convert iron to iron acetate and get the hydrogen. I’d speculate that if there is some grease still on the parts, you could also form a bit of an emulsion.