Tried saving a rusted chain with vinegar and it ate through the links instead

Last month I had an old 10-speed chain that was pretty crusty from sitting in a damp shed. I read online that soaking rusty chains in white vinegar can break down the rust without damaging the metal. So I left mine in a bowl of vinegar for about 6 hours and when I came back, the chain had actually snapped in two places and some of the pins were half dissolved. Turns out vinegar is acidic enough to weaken hardened steel if you leave it too long. I should have just used a citrus degreaser and a wire brush like normal. Has anyone else had vinegar eat through something it wasn't supposed to?

3 comments

3 Comments

scott.grace13d ago

@evah40 I actually had the opposite experience with a motorcycle chain I rescued last summer. I soaked it in a 50/50 vinegar and water mix for maybe 45 minutes, scrubbed gently with a brass brush, and it came out fine. I think the key is not leaving it for hours like I did on my first try. A short soak plus rinsing right away with water and baking soda neutralizes the acid before it eats into the metal. Maybe it's just me but I still think vinegar has its place for light rust if you keep an eye on the clock.

the_john13d ago

Vinegar is a trap for sure. I did the same thing with an old lawnmower blade a few years back. Left it in a bucket of vinegar overnight and it came out looking like someone took a cheese grater to it, all pitted and weak. For light rust on bike chains, a little WD-40 and a brass brush has always worked better for me without eating into the metal. If the rust is really bad, just replace the chain, they're cheap enough to not risk snapping on you mid ride.

evah4013d ago

Yeah, "cheese grater" is exactly how I'd describe it too. I learned my lesson with a rusty pair of garden shears, vinegar stripped off all the rust and then some, left them looking like they'd been through a sandstorm. For light stuff on my bike, I've had good luck with a little bit of mineral oil and a scotch pad, gentle but gets the job done without ruining the metal.