Anyone use onions on knives?

worldwood

worldwood

Joined
Sep 30, 2012
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so i recently read that onion slices will remove rust and help prevent rust, im wondering if anyone does this? i tried it on a old leatherman and it did work i just had to rub kinda hard.
 
Interesting. I don't know about removing light rust (though it sounds plausible), but as a preventative it would have to stay on the blade and that would tend to promote a patina (oxidation, aka rust) rather than prevent it. Seems so to me anyway. I know that an apple will create a patina on carbon steel in an hour or two.
 
copied from somewhere

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.

Read more: Why Do Onions Remove Rust? | eHow.com http://www.ehow.com/how-does_4635767_why-do-onions-remove-rust.html#ixzz29cBHaPFw
 
Can you patina a knife that has red rust? Or will it just create a patina where the red rust isnt?

EX: Stick a rusty knife into a potato and make the good rust change/eat away the bad rust?

This sounds kinda far fetched to me but i am not sure.
 
Yea its funny, alot of people cut onions haha thats a good one, yes there is a knife designer as well with he name onion, haha very funny.

Back on topic, Im not sure how you use onions to force a patina can you explain?, i force patinas by heating a vinegar mixture in the microwave then dunking for 1-2 minutes, works like a charm every time. i have used potatoes apples steak sauce mustard and so on but they all take alot longer and the results are always varied in appearance.

A patina in a way is a good rust, sulphenic acids in onions react to hydroxide ions in rust eliminating and neutralizing the acids, it seems onions would prevent you from forcing a patina. now using an onion first to clean the rust off and polish the blade, then forcing a patina makes more sense i think. Now im new, so feel free to correct me.

MEJ; you could use onion slices on the red rust and rub kinda hard, but from what im seeing it takes less rubing than sanding the rust off depending on how much rust you have, then put some vinegar or apple cider vinegar in a microwavable cup for a minute or so to get it really hot, it should be steaming, then take it out and drop in the blade, wait 1-2 minutes and voila.
 
It's not efficient to use onions as a rust remover, too slow and we make things just for the task that work much better.

The same acid that eats the rust will eat the steel. Patina is steels natural reaction to corrosive substances, think of it like a sun tan. When we are exposed to sunlight our skin darkens to prevent burning though if exposed too long we still burn. Patina works kinda the same way, the steel forms a oxide layer to prevent red rust but if exposed to the right conditions red rust will prevail.

The acidic levels of most vegetables and meats is enough to patina and discolor carbon steels in minutes.

I use a slice of onion and heat the blade in hot tap water, then rub the onion on the warm blade, rinse and repeat. I like to call it a 3D patina due to the layered affect.
 
I definetly agree the man made store bought chemicals work real fast and are made for the task. But not to be rude saying onions is not effecient is kinda wrong, just google rusty knives and onions. as a natural substitue it seems to work pretty fast for me, almost instantly on some things with only a little rust. im currently running around the house testing this out on nails knives and what nots. please try it before you say it just not effecient, i agree there are faster MORE EXPENSIVE, CHEMICALS you can use but this a cheap and natural method thats been used for years, i cant find any negatives, and most people have an onion already. Its working faster than sandpaper for me and also leaving the metal looking polished instead of all scratched up like sandpaper does.

Im all about learning, thats why i posted this. if you could explain why you think im wrong or why the onion would eat the bare metal after the rust is gone id appreciate it, but i cant find that online as being a possibilty.

Thank you knifenut for joinin me on this educational conversation.
 
I like to use barkeepersfriend for removing rust on knives, using a onion is not nearly as effective on as many levels of corrosion as BKF or other products. Red surface rust and pitting are two different cases and typically require different action. Onions work very well to a point, then it becomes beyond its capabilities.

BKF is also very cheap and has more uses, such as cleaning stones.
 
I have used bar keepers friend for cleaning pots and such before but not on rusty knives. i will probably try the polish out on something badly rusted or pitted to see how it works.

I agree with this "Onions work very well to a point, then it becomes beyond its capabilities."

if the rust is really deep or if the object is covered completly in rust i wouldnt even bother using an onion. but on a few small spots i wouldnt want to use harmful chemicals and i would use an onion. I feel It has its place but its definetly NOT THE BEST. its relatively easy, cheap, and safe and DOES produce great results as a substitute in my opinion.



But i also prefer herbals over man-made medicines, home grown over store bought, sun light over LED lighting and so on.
 
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