blackened steel


Well-Known Member

emmm fellas, i dunno why but it happened
here is how it happened,

i wanted to cut few strawberries, thought i would test that knife too. i sliced one, was checking how thin o cpuld slice it and such then noticed the knife was about to dry so i rinced it with water and while drying it (with tissue) noticed these stains started to appear. some parts are almost black

thing is the whole thing happened in less than a minute.

any idea why or how to clean?

the knife is O1 hand sanded to 1500 (altho now im starting to think i didnt do a good job with the sanding)

Many foods are very acidic. O1 being non-stainless you'll see this almost instantly depending on what you're cutting. It's nothing to do with your finish which looks just fine, just the acid darkening the blade. Fruit and meat in particular will darken a blade, and keeping it cleaned off will be a losing battle as you'll have to re-sand. I've had a guy bring back a 440C stainless knife to show me what looked like heat-coloring up from the cutting edge, he eats steak with it at camp and just wipes it off so there's a very distinct patina starting even with the stainless.
As Frank said, it depends on the action of that particular food. I have cut strawberries with a 52100 paring knife and got a very odd sulpher like smell. The area of the cut had blackened noticably. Just certin steels and how they react to various foods. I dont bthink this has anything to do with your level of finish on the steel.

God Bless
One thing I might add is the level of polish can affect the corrosion rate. Higher grits, polish, or mirror finish provide less areas for corrosives to cling to. A very rough 60 grit finish will flash rust immediately while I water dip it when I'm roughing the grinds in on a 1095 steel knife, while the final 45 micron + buffed finish just lets the water run off. And as for that smell, definitely. I do a mustard patina and it's not noticeable if I apply it to a fine finish, but smear that on some 220 grit roughed in machete blades and it's very stinky as there's a lot of "tooth" for the acid to go to work immediately on.
Well, thats unnerving...

Thanks a lot guys. Will still need to clean it to sell it tho :)
Well, thats unnerving...

Thanks a lot guys. Will still need to clean it to sell it tho :)

This is why I personally don't use carbon steels. Especially for culinary knives.

On that one that stained, You might try doing one of the etched finishes you were asking about?

Some call it a forced patina. I call it rust!:biggrin:

Laurence, i thought abought now, but it was just so elegant looking in the high grit finish!! Lol

Its not going to be easy establishing market this way...

Shawn, lol i like all steels too, i just guess some of them dont like me
I love carbon steels.

I love stainless steels.

I love ALL steels.

I love ALL Women! But I have preference & hold my wife Cecilia only. :biggrin:

If it was easy to be a knife maker? Everyone would be doing it! It goes back to our love of steel & the art and science's of making a knife.

In my previously jobs & lives etc in this body I have made more money!
Now it's about Passion.
I have a passion for making the perfect culinary knife! That is what I have striven for everyday over sixteen years and the income & opportunity's continue to build.

Keep your nose to the grind stone my friend!



Well, i guess every steel has its ups and downs

This makes me want to know everything i can on steel i work with, which so far are 5160, sverker 21, and O1. Any thoughts on where i can find that?

Best uses, worst uses, pros, cons, etc.

Also Laurence, problem now is not making (altho i still have loo-hong way to go) its selling, convincing people this is good specially when it rusts that easily (i told one guy you need to take care of the knife and he laughed at me. Thats how minds are totally oblivius to non- stainless steels here)
Also Laurence, problem now is not making (altho i still have loo-hong way to go) its selling, convincing people this is good specially when it rusts that easily (i told one guy you need to take care of the knife and he laughed at me. Thats how minds are totally oblivius to non- stainless steels here)

You need to build to the market to some degree, In your location it may be even more important.
Like Ed Caffey wrote to you, Educating your buyer is very important. But the level of custom knife & steel knowledge where you are sounds like none. All of the reasons that some maker's tout Carbon steels sound like they are lost on your country men.

Using stainless Steels may be paramount to your ability to sell your knives. You may find a few that like carbon steel in time. BossDog carries CPM-154, And 440C Both work fine, The 440C has been around a lot longer and is less expensive But does not have as good of edge retention as CPM-154 I use both and the 440C works fine for my Culinary knives and hunters when I make them.

SHOKR, patina is a beautiful thing, especially when you cut meats as it takes on hues of blue, purple, red and yellows. Most chefs I know use carbon and love it but you have to a stickler for cleanliness when using it. I use all carbon myself in my kitchen knives and it has become second nature to keep a towel to wipe the blade down after cutting.
Thanks Mike, will see how it goes :)

I want to try patina, but not on all blades, also it will be harmful for some who wont clean.

I guess more than anything I need to learn before educating the 'masses'

Laurence, i contacted the HTer who is bohler supplier again today, he will check an get back to me for N690 & N695(440c equivalent)

Buying steel online is REALLY costly, 1 FX rate, 2 will be shipping STEEL.

This will need some thinking and planning, especially since im running out of money...

Its true, carbon steel might be ok but not for everyone, and maybe not for food.

Thanks guys
In the state I live in of California and many other states in the USA it is against code and they can be fined for a Chef to use anything other that a Stainless steel knives because of unclean nature of carbons that are not watched and cleaned constantly. The pits can harbor bacteria.

To me patina is a beautiful thing when it's on the statue of liberty! When it's on a culinary knife, It's just rust and I don't want it in my food. Strangely enough, The Japanese prefer carbon steel because they are accustom to the way it flavors the fish. Go figure??

I suggest saving up and getting a digital oven to do stainless blades. I will but I'm more skint than you. I have been researching a lot about hot caustic bluing of O1, it gives it a bit of corrosion resistance. It will take some working out about times, temperatures and mixtures but it is worth looking into. That is my plan. Jay Fisher is a prime example of how good blued knives can be and not many people do it so it would help get your name out as well.
Thats bit strange

And i guess its matter of pereference but for now no kitchen. Thing is i am not making kitchen knives, moatly EDC or utility, but its given that at one point or another someone will want to cut food with them

Also remembered yesterday that i met local knife makers once that make kitchen knives from the gang saw blades (dont know the properties but carbon is high in that or at least mild)
Thinking about meeting them again and seeing how they do the whole thing and how people deal with any patina or rust, etc. I even bought a few kilograms to try.
The oxidizing incident of the blade gave me idea for test etching, will be using the same steel to try it.

Liam, thanks for the info, Jay Fisher's site has always been a lot of help
I will eventually check that, but for now its bit too advanced and probably costly too :D
Besides, so far i have limited quantity of O1, not sure if i will buy more or not (i got these when i bought the grinder), since i will have to buy steel anyway i get my choices that suit me now :) but thats a whole other learning experience...
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SHOKR, what about etching your blades all over with FeCl so they have a even layer of oxide. I believe it oxidises to a certain point and no more. It is cheaper than bluing also.
thanks Liam,
thats the plan for the most part now, i already etched the KDM with Cola (if i remember correctly) because i have no access to ferric chloride yet, and i plan on doing it to most blades that i think will see some serious rust/oxidization inducing use.