Removing Rust from Stainless Steel

TeaSpoon

So, I found one of those multi-tools in my garage. It was rusty, so I wanted to clean it. Not wanting to use any abrasives for fear of damaging the metal, I turned to chemical solutions. I wanted to soak it in some vinegar, having read about it online, but I was all out of vinegar.

Luckily, I found some sulfamic acid in the basement, which I used to boil the multi-tool. Well, not boil exactly, but I did cook it over a fire in the hopes that heat would make the acid react faster. Something went wrong. The multi-tool is all black now. My question: Did I do permanent damage?

I'm going to try scrubbing it with some toothpaste next.

[EDIT] Also, how do I get rid of the sootish material staining my multi-tool?

tinwhiskers

Don't use toothpaste. Thats going to be hell on the tool.

TeaSpoon

Okay, I won't. Thanks.

bowen

Hmm, have any pictures of it?

tapeslinger

TeaSpoon wrote: »

So, I found one of those multi-tools in my garage. It was rusty, so I wanted to clean it. Not wanting to use any abrasives for fear of damaging the metal, I turned to chemical solutions. I wanted to soak it in some vinegar, having read about it online, but I was all out of vinegar.

Luckily, I found some sulfamic acid in the basement, which I used to boil the multi-tool. Well, not boil exactly, but I did cook it over a fire in the hopes that heat would make the acid react faster. Something went wrong. The multi-tool is all black now. My question: Did I do permanent damage?

I'm going to try scrubbing it with some toothpaste next.

the metal should be fine, it sounds like what happened is the steel reacted to the acid and caused a patina of some kind. on stainless it should not be permanent. you may be able to take the patina (and rust) off with steel wool, but itll take a little elbow grease.

there are some cleaners on the market for this sort of thing but ordinary household abrasives ought to take the rust off. you'll need to scrub though, a solution by itself won't be adequate in most situations.

TeaSpoon

It's not a very good picture, but it's the best my laptop webcam can do.

[EDIT] I burned some food a while ago and messed up some pans. Someone recommended I soak it in vinegar, heat it, and add a spoonful of baking soda. It worked to some extent. The milky substance turned gray. I'm going to try it when I get my hands on some vinegar. It should work if the blackish stuff is indeed a carbon of some kind.

I'm having a lot of fun with my kitchen chemistry.

bowen

Yeah it'll probably wear off eventually, as it is, it's nothing to worry about, it'll still function.

matt has a problem

You've basically made black oxide. Think of it as rust that protects, as opposed to destroying.

tinwhiskers

Thats not bad at all, I was picture something more along the lines off you having oxidized all the chromium. That little bit of black is probably just some magnetite, which is good rust.

bowen

Yeah it's a similar process to gun metal I think.

TeaSpoon

I'll just leave it then.

At this point, I'm more worried about the rust that'll develop in the joints from having been rinsed with water after my misguided toothpaste debacle.

matt has a problem

TeaSpoon wrote: »

I'll just leave it then.

At this point, I'm more worried about the rust that'll develop in the joints from having been rinsed with water after my misguided toothpaste debacle.

Stick it in some rice overnight, or hit the joints with some WD-40, then oil them with some 3-in-1 oil.

TeaSpoon

I'll do that. Thanks everyone.

Djeet

Is this an effect you can get on any kind of steel? I have a cromoly bike frame that was chromed and then painted; the paint is flaking badly. I think I might like to try getting this or a blued finish on it.

tapeslinger

Djeet wrote: »

Is this an effect you can get on any kind of steel? I have a cromoly bike frame that was chromed and then painted; the paint is flaking badly. I think I might like to try getting this or a blued finish on it.

there are chemicals that do this; my preference is Birchwood Casey MKP Presto Black. I would also put a weather resistant lacquer for metal on that, something like Permalac, but an oil or wax would be easier to maintain.

Metalbourne

I kinda like the finish on that leatherman now.

TeaSpoon

That's because the resolution on that picture is shit. While not absolutely horrible, it does look significantly worse in real life. The black stuff also tends to rub off on your skin.

MrOletta

Evap-o-rust works wonders. I've used it on antique (80 year old) woodworking tools. You can buy it at your local harbour freight for $10 or so. I let it soak in the liquid in a disposable aluminum baking pan for a few days then hit it with a brass brush.

Psychotic One

3 in 1 oil + a steel wool usually does the job. either that or very fine sand paper.

illig

use WD-40 to clean it and displace all the water from the joints

then use an actual lubricant (i like white lithium grease) on the joints... should be fine.