Why does O-1 steel rust easier than SK5?

G

GrReaper

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Sep 22, 2014
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Like a lot of people, I have noticed that my O-1 knives will rust much easier than my SK5 knives. Why is that? I think O-1 has slightly higher carbon content, but is that enough to make that much of a difference? My SK5 knives seem pretty resistant to rust. All I do is clean them after every use, and they rarely develop any rust spots. On the other hand, O-1 develops rust spots all the time even when it hasn't been used.
 
I frequently carry an o1 fixed blade. I find that if I let it sit, it rusts. However, when I carry and use it for days or weeks straight, not a speck appears. Nothing academic, just something I've noticed. Wipe it down with some cooking oil at the end of the day and you'll be fine.
 
My Randall in 0-1 took stains while I rinsed it... Not washed it, it was clean: Rinsed it... I think the only solution is Cerakoating...

Gaston
 
Gaston444 said:
My Randall in 0-1 took stains while I rinsed it... Not washed it, it was clean: Rinsed it... I think the only solution is Cerakoating...

Gaston
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That Randall with a 12 degree inclusive edge probably chopped down a sequoia though with no edge damage right?

I don't live on the coast but it is pretty humid where I live and the last thing that's ever bothered me with a knife steel was corrosion resistance. My uncoated carbon steel knives all get some form of patina intentionally or otherwise, it's a silly thing to make a priority. O-1 is a fantastic steel used by many custom makers, we're lucky to have it.
 
I've never had a problem with any of my O1 knives rusting. They all developed a decent patina in the first few weeks of owning them and I rub them down with mineral oil from time to time.
A little preventive maintenance goes a long way.
 
Pretty well any high carbon steel blade will rust. Just dry 'em off before you put 'em away. Or wipe down with a rust preventive if they're not going to be used for a while. BreakFree works well for me, but there are lots of other commercial rust preventives, not to mention good old mineral oil.
 
C
W. Anderson said:
I frequently carry an o1 fixed blade. I find that if I let it sit, it rusts. However, when I carry and use it for days or weeks straight, not a speck appears. Nothing academic, just something I've noticed. Wipe it down with some cooking oil at the end of the day and you'll be fine.
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Cooking oils are not a good choice for rust prevention on a carbon steel blade. They can go rancid and pose a danger of infections if used to cut food, or from nicks on the skin.
 
I have a fixed blade in O1 that developed slight surface rust, and a couple small pitting spots. It was a bit odd because the other knives I have in 1095 did not, they were stored in the same container. I don't use anything in terms of oil that will decompose or evaporate. If you use the knife for food prep, mineral oil might be a good idea and wipe the blade before and after use. If not for food prep, you can use something a little heavier duty like motor oil, 3 in 1 oil, etc. Leave a medium heavy coat for a day or so then wipe away the excess. That will help for the most part, just my 2 cents.
 
Higher carbon can cause rust, yes. So can differences in heat treats and more so final finishes. When I use my rustable blades outdoors here in NC summers I keep a silicone cloth in a baggie nearby. I wipe it down during the day after use or when needed. It works better for me than oils. When I can I keep the knife cleaned of salts/acids then paste wax. These things take seconds of my time and reduce the problems greatly.
 
I bet mete mete knows why O1 rusts easily, chemically speaking!
 
I've gone through much of my life with carbon steels. We never worried about rust or patina . For example when food preparing we would never use then let the blade just lay around . At least run under hot water which will remove most food particles if you have to later continue cutting . The hot water will mostly evaporate When cutting is complete wash and dry immediately. Don't worry about the patina !! It will form and will actually protect the blade .We never oiled the blades just make sure it's dry !
A food grade mineral oil could be used or storage in VPI paper [rust inhibiting paper ]. Soap or detergent and HOT water does a good job [never soak knife or board ! ] Make sure the knife and board are dry before putting away.
Sorry Mecha but this is how a family [many involved in restaurants etc ] survived for generations . No magic .no special ingredients !!
BTW I just read advice for food safety which we always used but apparently new info for many - after you finished your dinner immediately put food away !! Warm food laying around for a long time is great for growing things !
 
I can only guess people who don't worry about rust on carbon steels have never used their knives while it rained heavily with no shelter... My 5160 knife, a low carbon steel, was severely pitted with hundreds of orange spots throughout its 11" blade in less than two hours... The leather sheath in which this happened hardly noticed, and I hate leather because it usually goes soft like a noodle in real wet conditions...

And no, I could not wipe the blade dry before sheathing, because it was raining, remember? Like I said, a good Cerakoat fixed that problem, but obviously a lot of hard core "woodsmen" tend to go out in more ideal conditions...

One thing you do find out is that a really wet log sticks to your blade like it was concrete poured around it, but I'll let the real woodsmen tell you the neat trick to get out of that predicament...

Gaston
 
I'm one of those who force a patina. I'd always used hot apple cider vinegar until I caught wind of a guy using his knife to stir his coffee in the morning. Over time, it put such a nice, sweet, even, gray, patina on the blade, which will protect against rust.
 
Gaston444 said:
I can only guess people who don't worry about rust on carbon steels have never used their knives while it rained heavily with no shelter... My 5160 knife, a low carbon steel, was severely pitted with hundreds of orange spots throughout its 11" blade in less than two hours... The leather sheath in which this happened hardly noticed, and I hate leather because it usually goes soft like a noodle in real wet conditions...

And no, I could not wipe the blade dry before sheathing, because it was raining, remember? Like I said, a good Cerakoat fixed that problem, but obviously a lot of hard core "woodsmen" tend to go out in more ideal conditions...

One thing you do find out is that a really wet log sticks to your blade like it was concrete poured around it, but I'll let the real woodsmen tell you the neat trick to get out of that predicament...

Gaston
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I dunno, man. I've used my o-1 piece in all sorts of conditions and put it back in its sheath wet (or snowy[or sweaty] {or bloody} ) and I've only had rust if I left it as such overnight. Spots in less than two hours?

Ehh.
I do lots of stuff outdoors and sometimes have no shelter for days at a time. By choice.

I also havent owned a car since 2004...

Off topic, though.
 
New "I can only guess people who don't worry about rust on carbon steels have never used their knives while it rained heavily with no shelter... My 5160 knife, a low carbon steel, was severely pitted with hundreds of orange spots throughout its 11" blade in less than two hours... The leather sheath in which this happened hardly noticed, and I hate leather because it usually goes soft like a noodle in real wet conditions..."

Your sheath didn't notice because it was too busy depositing salts/acids on your knife which combined with the humidity to begin the corrosion. No surprise and certainly no fault of the steel. Leave the pretty hand stitched leather sheath at home.

I suspect your idea of "severely pitted" differs from mine.

Have you thought about going into those conditions with a seal like paste wax on the knife? It wears off obviously in places with use but is more resilient in protecting the steels structure than many think. Naturally one would want a clean and dry surface to wax or oil .Not really smart to just glop stuff on salt still on the blade when you are back at camp or home. Wash the steel off then lube or wax.

Some folks really seem to make this stuff more complicated and worse than it should be. Tools were maintained for centuries with less than we have in much worse conditions. Also, why would my knife be in a wet log except in emergency conditions like a plane crash? I have an axe, maul, whatever I need when I expect to have to use them. Just part of planning and preparation. If you don't have what you need except in very unusual emergencies you have done something wrong. That means camping and bushcraft even when going light. Being an unprepared fool sure isn't my idea of recreation. I've lived, worked or stayed in every climate type our world has to offer. My favorites are arctic and alpine. Least favorite? Pretty much everywhere inland near the equator. Desert isn't that bad though.

Joe
 
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I put Obanuaf's on my non stainless blades. Works great and taste good too.
 
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