Removing Rust

[Rhysito]

Thanks for all these really great responses. I have learnt a lot. I am really just trying to get superficial rust off parts. Once I have used foil / metal wool to remove the rust, do I need to seal the area?

 

[Punkawallah]

I'd go with foil rather than wire wool, at least initially. It's less harsh. Those don't look too bad, at all. As for a 'seal', a wipe over with a rag sprayed with WD40 or similar should do - don't get any on the brake surfaces, though :-)

 

[battered]

If you are dealing with small parts, I have a suggestion. Get a plastic tub, ideally with a lid, and fill it with vinegar. Normal malt vinegar from the supermarket, 25p a bottle in Aldi. I used to make the stuff in a vinegar brewery in the W Midlands. Chuck the parts in, leave them for a day or two, fish them out and brush them. Repeat as necessary. This will not hurt sound metal, but rust will come off. After you have done this you will have to coat it with something, because you are looking at totally bare steel with any plating that may have been applied no longer there and the rust removed. If you leave it in the rain overnight, it will be brown in the morning. A coat of oil will help, paint is obviously better.

 

[battered]

Oh, and those parts in the photo will clean up fine. They just need degreasing first with either petrol/paraffin followed by hot water and Fairy liquid, or a proprietary degreaser/bike cleaner like Muc-off. Then soak away. You can see that the original parts were probably BZP, meaning Bright Zinc Plated, which is a poor man's galvanising used on fasteners and small parts that need to look bright for a while. Zinc is sacrificial, so it corrodes before the steel. Once it has gone, the steel corrodes with the characteristic brown rusty stains.

Of course, if you really want to have fun, you can set up a DIY electroplating rig (look on You Tube) and restore the parts to original condition. This will however cost you more than new parts.

I have a modern steel penny that I found at the side of the road. Of course pennies used to be made of copper, but there was more than 1p of copper in them so scrap dealers started melting them down, and they went to steel and a copper plating. Leave them in the rain, they rust. The one I found I put in vinegar for a week, it started as a blob of rust and is now a clean grey metal disc with odd bits of copper still in place.