Lemon juice works too but not sure if it takes off bluing which is a type of rust itself.
I saw it on YouTube . A lady using on a shotgun
Why Do Onions Remove Rust?
Sulphenic acid, like all acids, reacts strongly with anything containing hydroxide ions. Rust happens to be such a substance, containing one hydroxide ion for every atom of iron in the compound. When a cut onion is rubbed against something rusty, the sulphenic acid within the onion breaks down the rust, causing it to flake away, leaving behind any untouched layers of iron beneath the rust coating. This process also happens to neutralize the acid. So if you're trying to remove rust from an item by this method, something with lots of rust may require more than one slice of onion.
The video here
https://youtu.be/9aCbiO8alDY
Lemon juice works too but not sure if it takes off bluing which is a type of rust itself.
Last edited by bighit; 13-09-2017 at 07:14 PM.
Bighit wrote: "...the sulphenic acid within the onion breaks down the rust, causing it to flake away, leaving behind any untouched layers of iron beneath the rust coating"
That's very interesting, but begs a question as to what to do with that nice clean 'iron" that's been exposed so it does not rust again?
Jim [making up for sleeping through middle-school chemistry]
Cold blue it. There is cold blue pens , liquids and gels.
I used acetone to degrease the area and used Philips bluing gel http://www.capdevco.co.uk/phillips-gun-products.html
I did a full Hw80 with it. The Hw80 had pitting and rust as it had been left in a barn on the farm by my nephew.
I got the rust off and degreased the full rifle then used the gel all over the rifle action and barrel.
It looks good but obviously not like a re blue by Colin malloy or RichardH from this forum.
Paul
Polish with oil now and then and after a while it will look better.
My airguns: https://barx.org/airguns/
I would have thought that Onions, lemons or acidic anything would remove the bluing, it is after all rust, that's why I scrub with oil.
G'day,
I treated the FWB with very fine steel wool and oil as gently and carefully as I could and the just visible rust specks are not visible any more.
Thank you all for your advice and I will keep the metal well clean with a wipe down after each use.
Jim.