Rust removal?

[marknotgeorge]

Citric acid works as well, in the same manner as the phosphoric acid in coke and some commercial rust converters, and the tannic acid in other commercial rust converters. Reasonably cheap, too.

 

[yadder]

Yeah citrcic acid very nice!

 

[GuyBoden]

£3 for a 125ml bottle at ToolStation.

 

[AndyBa]

If you can remove the rusty part, ie my mountain bike pedal has a metal outer and a plastic inner. Then you could soak them in a dilute molasses mix. Its what farmers use but you can just get Molasses granules from the supermarket and dilute it (Billings Molasses £1.50 a pack from Morrison's) . Leave it soaking, the longer the better. See vids on Youtube.

I've used it on some very badly rusted trike steering arms and after 2 weeks soaking in the molasses brew they were bright shiny metal.
Last week I left all 3 of our rusty bike chains (one was rigid with rust/neglect-the wife's) in for a day, scrubbed with a wire brush, rinsed and re-oiled all nice and floppy (tbh one probably needs replacing, but its brought me more time).

 

[KnackeredBike]

An angle grinder will bring them up lovely and shiny.

 

[Alan O]

Coca-Cola. Look on Youtube for a guy who derusts the chrome bumpers on his car with it.

Coke contains mild phosphoric acid*, and is only a diluted version of the active ingredient in Kurust and Jenolite. It converts iron oxide (rust) to ferric phosphate, which is inert. Paint it on, leave for a bit, wash it off and then apply oil or wax to inhibit further rust. If your rusty bits now look black, it's worked. If the pedals are chrome plated steel, then bear in mind that by the time you can see rust, the chrome layer has already been pinholed, and further rusting is inevitable, so you will need to keep on top of it.

*It's what gives the drink its tangy flavour, and is the reason why I never drink it.

I'm old enough to remember being able to buy phosphoric acid from the local chemist. I was about 12 at the time and when questioned I said my dad sent me to get it for removing rust from garden tools, and the guy fell for that and sold it to me. I actually wanted it for some home chemistry experiments (can't remember what, specifically, now), and I needed to titrate a sample to discover its molarity first - and it turned out to be surprisingly concentrated. Still, it came in one of those ribbed bottles that denoted "nasty stuff", so what could have gone wrong?

Oh, I also remember buying hydrochloric acid from a chemist, which turned out to be approximately 10 molar, and that's pretty corrosive. I can't remember what reason I gave for that, or even if I was asked, but it was around the same time - I tried local chemists because my favourite local chemicals supplier (Oakes & Eddon in Liverpool, it was) would only sell me dilute stuff.

 

[davidphilips]

Unless the pedals are very rare or expensive then why not just give them a rub them with some sand paper and put some paint on them. You could spend a bit of time and effort removing the rust but it will more than likely return unless they are painted or chrome plated any way.