First Time with Iron Clad Knife - Patina Questions

Proper user technique and care is essential to enjoying these high performance knives to their fullest while keeping edge damage to a minimum. Learn how here.
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ambjeb
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First Time with Iron Clad Knife - Patina Questions

Post by ambjeb »

Hi! This was my first time using an iron clad, White #1 knife. I attached pictures of what it looked like after use. I was really surprised just how reactive it was. Is this a normal, healthy occurrence? I cut two onions, wiped the knife with a damp cloth after each half, didn't let it sit. When complete, I washed with soap and hot water, before drying it completely? Knife was on the board maybe 30 sec after being wiped down before washing and drying. I had to remove something from the onion. Love the knives, love the finish, look forward to zen like sharpening with them, I just want to make sure I am caring for them properly
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Re: First Time with Iron Clad Knife - Patina Questions

Post by ken123 »

You're fine. This is normal patina. Dry the knife off more thoroughly. I highly suggest using a microfiber cloth which will dry your knife MUCH better.

---
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Re: First Time with Iron Clad Knife - Patina Questions

Post by bruin »

Common moment of doubt with one’s first reactive knife... alliums (especially juicy onions) can cause brown/tan patina that can be mistaken for rust.
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Re: First Time with Iron Clad Knife - Patina Questions

Post by Jeff B »

Very normal, you did just fine. No need to change a thing.
If God wanted me to be a vegetarian he wouldn't have made animals taste so good.
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Re: First Time with Iron Clad Knife - Patina Questions

Post by Kalaeb »

Reactivity will reduce once a stable patina is built up. It will gradually get darker and cover more area, but what you are seeing is totally normal.
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Re: First Time with Iron Clad Knife - Patina Questions

Post by ambjeb »

Wow, I knew I was going to love this community when I started exploring the site! Thanks for the quick responses! It was certainly a bit disconcerting to see at first, but I am glad I just having first knife jitters!
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Re: First Time with Iron Clad Knife - Patina Questions

Post by Jeff B »

If God wanted me to be a vegetarian he wouldn't have made animals taste so good.
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Re: First Time with Iron Clad Knife - Patina Questions

Post by Corradobrit »

Some knives are more reactive than others. A lot skip the dirty browns and go straight to rainbow blues and oranges. I find my Kato's and Honyaki's do the latter.
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Re: First Time with Iron Clad Knife - Patina Questions

Post by ambjeb »

Thanks all again! How often should I use camellia oil? If i hang the knives for a week if I am out of town? If i dont use them for a few days? I like in Germany so some days are rainy, some days arent?
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Re: First Time with Iron Clad Knife - Patina Questions

Post by d_rap »

I'm in LA, so relatively arid, but especially in a humid climate and for some days on end why not a light coat of oil (I like food grade mineral oil)? Takes a minute, and since you're hanging them there's nothing to get oil on, no mess.

That patina is beautiful by the way. On my all-reactive knives the patina makes me feel like the steel is alive. Big part of the fun!
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Re: First Time with Iron Clad Knife - Patina Questions

Post by salemj »

To answer your original question, I would call that VERY reactive.

I have never wiped off a knife with a damp cloth between cuts of a single ingredient, washed and dried immediately, and ended up with a patina like that. Even on my most reactive, brand-new knives, there was usually only the slightest patina after a first meal prep.

The good news is that it only means the patina will develop faster, and once it does, you have nothing to worry about. Given how reactive that knife is, until you have a patina on the whole knife, you will want to be careful about letting them sit out in a humid environment if you are gone for a while, but after they have developed a full patina, you shouldn't have to worry. I've been gone for 1-2 weeks frequently in a coastal climate and I have never oiled my knives during a vacation.
~Joe

Comments: I'm short, a home cook, prefer lighter, thinner blades, and own mostly Konosukes but have used over a dozen brands.
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Re: First Time with Iron Clad Knife - Patina Questions

Post by d_rap »

salemj wrote: Sat Jun 20, 2020 9:34 am To answer your original question, I would call that VERY reactive.

I have never wiped off a knife with a damp cloth between cuts of a single ingredient, washed and dried immediately, and ended up with a patina like that. Even on my most reactive, brand-new knives, there was usually only the slightest patina after a first meal prep.

The good news is that it only means the patina will develop faster, and once it does, you have nothing to worry about. Given how reactive that knife is, until you have a patina on the whole knife, you will want to be careful about letting them sit out in a humid environment if you are gone for a while, but after they have developed a full patina, you shouldn't have to worry. I've been gone for 1-2 weeks frequently in a coastal climate and I have never oiled my knives during a vacation.
Image

Totally respect your response and experience Joe, but just a different first-time experience. Here's my new Konosuke FM in Blue 2 steel with the reactive cladding featured on these knives, after my first long prep session with the knife a month ago. I cut raw pork and later sliced it cooked, minced garlic, onions, cut turnips, parsley, and a number of other ingredients, and I am very careful, even fanatical, about rinsing, wiping and drying between ingredients. My first of these famous knives, I was extremely cautious, and couldn't believe what was happening to the knife. I was afraid at first. But as I looked at pics here and around the web, and as the days went by, I became more comfortable with the way the knife was reacting. I have some later patina pics in the new knife sub-forum and I could re-post them, but the patina that has developed is absolutely gorgeous to me.

The oiling seemed like a why-not to me, easy enough, but I appreciate the response. A good patina and you're probably good to go.

And on the how reactive question: I'm sure it somewhat depends on the length of a cutting session with a particular ingredient before rinsing, the ingredients in question (proteins are highly reactive, onion family as well) environment and an array of other variables. Just to say I had a similar somewhat extreme experience and it is all working out for the best.
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Re: First Time with Iron Clad Knife - Patina Questions

Post by Radar53 »

salemj wrote: Sat Jun 20, 2020 9:34 am To answer your original question, I would call that VERY reactive.

I have never wiped off a knife with a damp cloth between cuts of a single ingredient, washed and dried immediately, and ended up with a patina like that. Even on my most reactive, brand-new knives, there was usually only the slightest patina after a first meal prep.
Yeah, I've had an experience like the OP as well with a Yauji carbon core, carbon clad knife, where it seemed VERY reactive to me as well. I'm pretty fastidious with my stuff and rinsed wiped often. I had just assumed that for some reason it was a "one off" thing, but maybe it's more common than I thought.
Cheers Grant

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Re: First Time with Iron Clad Knife - Patina Questions

Post by taz575 »

I usually use Ferric chloride acid diluted to acid etch my carbon blades for a short time so the surface reacts to that. Really seems to help tone down and control the patina and make it look more even since the steel has reacted to the acid already. Ferric chloride is used to etch circuit boards and is fairly common. I think I use 1 part acid to 10 parts water or something? It's a very dilute acid solution. Others use 1:4 acid to water to etch damascus blades. My solution is over 7 yrs old and I can't remember the ratios!
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Re: First Time with Iron Clad Knife - Patina Questions

Post by TheLegalRazor »

I have a similar question and could use some guidance. This is my Kato after one use. AS, iron cladding, and Kurouchi. For its first use, I cut tomatoes with it. I never wipe a blade between cuts, but follow a strict regimen after completing the cutting. Immediately after using the Kato, I rinsed it with soap and water, dried it, and coated it with mineral oil. The next day, there were gold and pale orange spots on the Kurouchi on one side of the knife. There are no other marks anywhere else on the knife.

Is this normal patina? Does patina develop over Kurouchi? Due to how I cared for the knife immediately after using it, I would be surprised if this was rust. If it is rust, I need to address it.

Thoughts, please?
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Re: First Time with Iron Clad Knife - Patina Questions

Post by jacko9 »

Looks fine just like my iron clad knives. For comparison this is my 45 year old 1090 steel 12" chefs knife. It sits in my knife block and gets used with just casual wiping when I think of it. There is no rust on that knife ever.
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Re: First Time with Iron Clad Knife - Patina Questions

Post by Jeff B »

I'd be surprised if that actually is iron cladding since there is no discoloring on the blade road but there is on the core steel. It looks like a it's bead blasted stainless to me. I'm not aware of Yoshimi Kato making anything that is iron clad either but I definitely could be wrong.

The discoloration on the KU is not uncommon. KU finishes can have iron or steel particles in it that will oxidize. Wipe the knife with a dry paper towel and if there is any rust it will show on the paper towel. Patinas can present in oranges and reds and not be rust.
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Re: First Time with Iron Clad Knife - Patina Questions

Post by 7x57mm@gmail.com »

I realize this is quite an old thread but I thought I would share. My Mom used (the same) carbon steel knives for close 60 years . The blades themselves were jet black, like black obsidian. When I'd come to visit, I would sharpen those knives for her. The black patina was almost plastic like. The knives took on a really cool look with a freshly ground shiny bevel. Those black patinaed knives were probably more rust resistant than stainless steel :)
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Re: First Time with Iron Clad Knife - Patina Questions

Post by 7x57mm@gmail.com »

Tojiro ITK Petty, purchased Jan 1 2021. I have used this knife daily in one fashion or another. The patina changes daily, depending on what I cut. The most dramatic change so far came from chunking up a can of San Marzano plumb tomatoes. The seeds did some cool things. Vinegars have basically done nothing (20 minute soaks). Standard yeller mustard (used the knife to spread mustard on a couple of grilled hotdog buns) had some cool effects. The Kuriochi finish on the right side of the blade has pretty much faded....left side of the blade's K finish almost looks like the day I received it 🤷🏻‍♂️

Long story short, I plan to use it, clean it, oil it and see what's what down the road....keeps the daily doldrums at bay ;)
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Re: First Time with Iron Clad Knife - Patina Questions

Post by stewssy »

Normal, once it turns brown then it’s rust
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