Distinguishing Super Blue colors and rust and pitting

[mcb]

I'm a noob when it comes to carbon steel can anyone explain the differences in the colors of SB and how to tell if it's really rust or pitting? What will it look like? I've tried searching but haven't found any pictures of rust on SB. I have seen some great patinas, but some of them have some reddish, yellowish and somewhat orange. Is this just the patina or is it rust? Also what exactly is pitting? If the blade has some circular rings, is that pitting or what?

Thanks guys and sorry for all the newbie question!

[Clip]

Patina starts as a haze on SB and most other carbon steels. I noticed a myriad of colors on mine. It's easy to spot rust as its the usual orange/iron oxide color. Here are a few pics of the patina after a week of carry.

[mcb]

Very nice! From my viewpoint, it looks somewhat orange near the edge. Is it safe to say that if it looks somewhat "milky" or blended, it isn't rust? Will rust be that dirty, chopping looking stuff like normal rust would be?

Also will it easy to take off that rust with some mineral oil and a cotton ball or qtip or something without affecting the patina?

[Clip]

You won't have to worry about rust as long as you wipe the blade after use. The blade is darkened at the edge fading into a bluish. It eventually got more gray and aged. I took it off with flitz polish and started over too, same results. If you've seen old kitchen knives with staining that's similar to what this will do

[mcb]

Thank you for the info Clip! Maybe I'm just thinking about it way too much lol

[Liquid Cobra]

So how does one stop any form of patina happening. I've forced a few, but if I wanted to maintain patina free how would I do that? Does super blue always have to covered in oil???

[mcb]

I've heard that tuff glide on the blade prevents patina, but it shouldn't be used for food prep.

I'm just not going to worry about it. I'm just going to use it, keep the pivot, tang oiled with mineral oil and keep it clean. Every night or a couple nights, I'll check the blade and use a pencil eraser if necessary for rust.

Is it advisable to have the jimping oiled as well? Or will keeping it clean be good enough?

[phaust]

I've heard that tuff glide on the blade prevents patina, but it shouldn't be used for food prep.

I'm just not going to worry about it. I'm just going to use it, keep the pivot, tang oiled with mineral oil and keep it clean. Every night or a couple nights, I'll check the blade and use a pencil eraser if necessary for rust.

Is it advisable to have the jimping oiled as well? Or will keeping it clean be good enough?

If you don't want rust, jimping, too, needs oil. It's generally a rougher finish than the blade, which makes it rust easier, plus you put your fingers on it, and that will also make it rust.

[Clip]

I put Tuf-Glide on the jimping, tang area of mine. Kept any oxidation from occurring as you can see in the pic I posted earlier.

[Scottie3000]

Basically, black and blue colors are patina and that will actually add some protection against orange and red colors which are rust and should be removed immediately.

[mcb]

Nice! I definitely feel that I'm over thinking it. Basically, keep the blade clean, wipe it on my pants after normal use and wash and dry after food prep correct? And rust SHOULDN'T form. If it does, just pencil erase it? Reason I'm thinking about it so much is I live on an island so I'm near the ocean but I love the patina of carbon steels so I'd like to EDC it.

Also, depending on what you cut, can there be etching but no rust?

Finally, is rust easy to spot? For instance, is rust more rough than the good kind of patina? Reason I ask is after looking at some patinas, I noticed some orange that appears to be rust, but it isn't? or the user doesn't really care lol

[Clip]

This steel behaves like any other. If you've ever spotted rust on steel, you'll be looking for the same signs on your SB blades. Hard to give specifics. Just use it normally and it will patina instead of rusting.

[mcb]

Thanks Clip! So don't worry if I see a little orange hues, it's just the patina developing?

[Clip]

That's correct

[DougC-3]

It would be good if an inorganic chemist could chime in and tell us about the different types of oxidation that are going on. Some of it doubtless involves elements other than iron and, hopefully, might even protect the blade from iron oxidation (rust ). I think the oxides of some metals, such as copper and aluminum, can be self-limiting by forming an oxide layer that keeps oxygen from reaching the surface (yes, I know there's no copper or aluminum in our blades ). Maybe that's why sometimes patina seems to stop by itself at some point, like my hair length :D

[Cliff Stamp]

What you are seeing is iron oxide, it is all rust. The main difference is that the orange type (Fe₂O₃ ) is a volume expansion and thus it is instable, you can scrape it off very easy. The black oxide (FeO ), commonly called a patina is still rust, it still weakens the steel, it in fact consumes it to make the oxide. However as it isn't a volume expansion it is fairly stable and if if forms gradually over time it will build up a thick layer and this will act to prevent (but not make it impossible) for the orange type to form.

[DougC-3]

Thanks, Cliff. I was hoping you would comment on this. So it appears that if we pay attention and watch what we're doing, we can actually get a somewhat protective patina coating on some of our non-stainless blades. I've seen some in photos that almost look like they have a thin galvanized layer on them. I know that's far from what it actually is, but it's nice to know that patina can sometimes be useful instead of just decorative.

[mcb]

So in theory since the orange stuff is easy to scrape off, at first sight, a finger nail or pencil eraser can take it off but not the black oxide?

Thanks for the explanation Cliff!

[Cliff Stamp]

This is a fairly old natural patina :