How to ruin your new super sharp knife within minutes

Here a story about what not to do with your new knife! I got my new Toyama Noborikoi 240mm gyuto two days ago. I really liked it right from the beggining.

I used it for a meal prep at home and it was delightfull. A real workhorse, extremely sharp right out of the box. Yesterday after having done some reading (it's my first carbon knife i forgot to say) i decided to force a patina to it, as even though i had done everything i could in order to take good care of it (wipe with damp towel after each task or every a couple of minutes max and then with a dry one) a patina had already started to form right from the first onion i cut.

So i used some mustard with a bit of water and a bubble wrap in order to force a patina. The result wasn't nice and a small rust spot also appeared, so after some extra reading i decided to remove the rust spot and the patina by using baking soda and a scotch brite. I've read that in Japan they do someting like that everyday and keep the blade shiny instead of letting a patina form. So i did and guess what, after that my knew knife cannot cut a newspaper no matter what i do when yesterday i was just pushing it down the newspaper with ease. It's impresive the difference after the procedure i followed, the razor sharp edge has completely gone just like that.

Well i'm sure i can do something to resolve this problem but i'm a bit lost know whith this situation.

Please help your stupid friend here repair his new knife

P.S. I would have tried to polish the blade with something like a 4000-6000 grit stone if i had one, but since my highest grit stone at the moment is only 2000, i'm afraid that this is not a solution till i buy a polishing stone

You can easily sharpen your knife on your 2000 grit stone. Technique is often more important than tools. You can get a very serviceable edge from a 2k stone and a bit of stropping on leather or newspaper.

Welcome novo,
I'm no expert, and there are many more experienced people here but we'd probably all agree you've likely done no lasting harm so don't panic. As far as I know, most knives out of the box are sharpened at a relatively low grit. To get your knife back in good order a 2k stone should suffice if you were happy with the edge before. Many of us here have concluded over time that sharpening technique is 1,000x more important a high grit or expensive stone set. I personally like a 4K edge for kitchen use.
Patina is up to you really, some like it some don't. My suggestion would be to avoid facing a patina, just let it happen over time. Keep the knife dry and oiled (get some tsubaki oil and make an oilcloth from a scrap towel or shirt) when not in use.
Damaging knives can have an upside, you may learn more about caring for it and become more relaxed using it afterwards.
Cheers
Matteo

+1 to the above. 2K can get you there.

To polish the blade face I start with Bar Keepers Friend (BKF) to remove patina then go with wet sandpaper. Do this first then sharpen. To establish a real patina, make some chili. Cube 3 - 5 lbs of your favorite beef then wash and dry. Repeat.

A rust eraser (Amazon) will help spot clean any uglies you pick up.

Well thanks for your answers guys, but can you explain what happened here and i transformed my super sharp knife into an absolute dull one just by using mustard, baking soda and a scotch brite sponge !!!

I really need to understand what happened here

The corrosive stuff and probably the ScotchBrite etched respectively abraded some of the fine edge. First thing to do after applying mustard is to clean the very edge, or you will end up with a very coarse edge. As for the ScotchBrite, it will round and dull any edge. Your knife is far from being ruined, just needs a good sharpening.

Benuser said:

The corrosive stuff and probably the ScotchBrite etched respectively abraded some of the fine edge. First thing to do after applying mustard is to clean the very edge, or you will end up with a very coarse edge. As for the ScotchBrite, it will round and dull any edge. Your knife is far from being ruined, just needs a good sharpening.

Click to expand...

Exactly what he said. In my experience (only limited to a White #2 Gesshin Ginga and an 01 damascus Ealy) if you even cut reasonably acidic products that can be enough to dull the edge of your knife carbon knives. Stainless seems to stand up better, but it does still dull them.

Yep, what you did might have ruined the factory edge (which was probably good, but not necessarily great), but you surely didn't ruin the knife.

Sounds ruined. I'll buy it from you at a discount. :2thumbsup:

Also, try applying baking soda with a champagne(or wine) cork. I add a drop of water to baking soda to form a slurry.
An if I were you, I'd try light edge trailing (stropping) strokes on your 2k first to see if this gets you to where you want to be. If not, go to town with that stone

I saw on television a japanese chef explaining how he cleans his knives daily. I guess in Japan they don't view a patina as desirable. What he did, and it works extremely well, was to slice off a 2 inch piece of daikon and dip that in some bar keepers friend and then use it as a polisher. The daikon is just spongy enough to make contact across the entire surface and it keeps the BKF moist enough to polish off the crud....works like a charm if you want to polish your knife.

A few comments above poo-poo'ed the 'factory' edge on the new Toyama, probably with the idea that the thread starter shouldn't worry, not all is lost, and he could end up a lot better in the future which is often true. However, I just received a Toyama and I'd have to say the edge it came with and cuttability from the start was very impressive - in fact, I think the best initial edge and condition I've seen - and so it's too bad that that was lost. Not sure to what extent Maxim might have put an edge on it, or if this was Toyama's original. Maybe the latter? Great stuff.

Agree, though that with such a good knife you needn't worry about the ability to fix it up. The patina removal - rubbing the edge, or maybe pressuring the edge against something as you scrubbed - was certainly the culprit. Sure, reactions with your mustard, etc, can have an effect too. Don't fret, though, as edges are like haircuts and won't last. Have to get to know the knife.

Smurfmacaw said:

I saw on television a japanese chef explaining how he cleans his knives daily. I guess in Japan they don't view a patina as desirable.

Click to expand...

Sure. I actually felt a little embarassed yesterday as I sent a knife photo to a maker, and there was a small bit of patina, and I definitely felt the need to apologise. Not sure of the Japanese term, so did a traslation for 'discolouration'

i was told, in no uncertain terms by my former chef, that Japanese chefs view a knife w patina simply as a lack of care.

Asteger said:

A few comments above poo-poo'ed the 'factory' edge on the new Toyama, probably with the idea that the thread starter shouldn't worry, not all is lost, and he could end up a lot better in the future which is often true. However, I just received a Toyama and I'd have to say the edge it came with and cuttability from the start was very impressive - in fact, I think the best initial edge and condition I've seen - and so it's too bad that that was lost. Not sure to what extent Maxim might have put an edge on it, or if this was Toyama's original. Maybe the latter? Great stuff.

Agree, though that with such a good knife you needn't worry about the ability to fix it up. The patina removal - rubbing the edge, or maybe pressuring the edge against something as you scrubbed - was certainly the culprit. Sure, reactions with your mustard, etc, can have an effect too. Don't fret, though, as edges are like haircuts and won't last. Have to get to know the knife.



Sure. I actually felt a little embarassed yesterday as I sent a knife photo to a maker, and there was a small bit of patina, and I definitely felt the need to apologise. Not sure of the Japanese term, so did a traslation for 'discolouration'

Click to expand...

Exactly that's the situation. The factory edge was just amazing and i'm so sorry and surprised i ruined it so easily :cry::cry:

IndoorOutdoorCook said:

Sounds ruined. I'll buy it from you at a discount. :2thumbsup:

Click to expand...

:rofl2:

novo said:

Exactly that's the situation. The factory edge was just amazing and i'm so sorry and surprised i ruined it so easily :cry::cry:

Click to expand...

No need to worry. Plenty of knives develop their full potential only after they have been sharpened a few times.

Asteger said:

A few comments above poo-poo'ed the 'factory' edge on the new Toyama, probably with the idea that the thread starter shouldn't worry, not all is lost, and he could end up a lot better in the future which is often true. However, I just received a Toyama and I'd have to say the edge it came with and cuttability from the start was very impressive - in fact, I think the best initial edge and condition I've seen - and so it's too bad that that was lost. Not sure to what extent Maxim might have put an edge on it, or if this was Toyama's original. Maybe the latter? Great stuff.

Agree, though that with such a good knife you needn't worry about the ability to fix it up. The patina removal - rubbing the edge, or maybe pressuring the edge against something as you scrubbed - was certainly the culprit. Sure, reactions with your mustard, etc, can have an effect too. Don't fret, though, as edges are like haircuts and won't last. Have to get to know the knife.



Sure. I actually felt a little embarassed yesterday as I sent a knife photo to a maker, and there was a small bit of patina, and I definitely felt the need to apologise. Not sure of the Japanese term, so did a traslation for 'discolouration'

Click to expand...

Maksim doesn't sharpen Toyama knives before sending them out. They do have a near perfect factory edge. But OP should very easily be able to bring it back.

Asteger said:

Not sure to what extent Maxim might have put an edge on it, or if this was Toyama's original. Maybe the latter? Great stuff.

Click to expand...

DamageInc said:

Maksim doesn't sharpen Toyama knives before sending them out. They do have a near perfect factory edge. But OP should very easily be able to bring it back.

Click to expand...

Good to know and, yes, it didn't look like the edge had been touched along the way from Japan.

One I thing I try to do is to remember how the knife is when it arrives, because otherwise after that it'll just be my own work and I want to know how that compares. Hope novo has some recollection of the edge and so can recreat it, considering how good it probably was.

mhpr262 said:

No need to worry. Plenty of knives develop their full potential only after they have been sharpened a few times.

Click to expand...

Already discussed above, this one could have been the exception and I think already there.

Smurfmacaw said:

I saw on television a japanese chef explaining how he cleans his knives daily. I guess in Japan they don't view a patina as desirable. What he did, and it works extremely well, was to slice off a 2 inch piece of daikon and dip that in some bar keepers friend and then use it as a polisher. The daikon is just spongy enough to make contact across the entire surface and it keeps the BKF moist enough to polish off the crud....works like a charm if you want to polish your knife.

Click to expand...

The powder that the daikon was dipped in was likely not BKF, but rather a mild abrasive like Bon Ami. BKF contains oxalic acid and will actually cause a patina.

BKF is weird in that it removes an existing patina and can add a new special BKF patina. The issue is that the BKF patina will come off all over your first onion.
Use BKF to remove existing patina and light rust, but then baking soda after to clean off the funky BKF patina and neutralize the Oxalic acid. Dry and oil right away. Now sharpen and enjoy.

Asteger said:

Already discussed above, this one could have been the exception and I think already there.

Click to expand...

I'm not talking just about sharpness, but also about durability and brittleness/microchipping. If it was that sharp out of the box, it will always be possible to get it at least as sharp again.

Hey Novo, sorry this happened to your brand new knife. I recommend using camelia oil its an amazing non toxic way to force a patina on your carbon steel knives without doing any damage to them! You can literally just spritz a little on the blade let it sit then wipe it off with a cotton material rag. I have also found using a 3000/8000 combo polishing stone works the best at bringing back that shiny polish. Good luck!

mhpr262 said:

If it was that sharp out of the box, it will always be possible to get it at least as sharp again.

Click to expand...

Definitely, and I look forward to sharpening this one - although, unusually, not to seeing the edge it came with wear away. I've used it a few times now, and nothing heavy, but no real signs of wear yet though. Just the right combo of fineness, durability so far and very little brittleness. Impressed again; I seem to sharpen all new knives the day I get them but not with this one.

About bringing back any polish, these are nicely done with some fine jnat material of some sort; not exactly sure of the technique. But the design and finish really is made so that it's pretty straightforward to care for and restore, and it's not a big chore and can be a little enjoyable to do.

There's been many a time when I've sharpened my knife, then decided it wasn't shiny enough or I noticed a scratch and started going at it with sandpaper and/or barkeeper's friend. I almost inevitably dulled my edge in doing this, so now my rule is rub out any spots or scratches first, then sharpen. I've recently decided to give up trying to keep my carbons shiny anyway. The freshly exposed steel tends to react with some foods, transferring odors, turning onions brown, etc. You're better off allowing a patina to develop, in my opinion. For my Tanaka 7" Santoku (blue #2) I placed the bade in a glass full of cider vinegar for about an hour, with some paper at the bottom of the glass to protect the tip, and being careful not to get any vinegar on the handle. I was pleased with the result and the edge did not dull.

Scotchbrite pads are very abrasive and you can think of them as a spongy sandpaper. That is likely what dulled your edge so immediately. A quick sharpen on your 2000 stone and strop will fix it right up.

JeffSwanson, thank you for that tip. I knew I always wanted a bottle of camelia oil for some reason... !:laugh:

For the future if you decided to just remove patina (natural or forced one) than just get some very fine polishing paste (e.g. simichrome) or just when you next time flatten your 2000 stone (or finer should you get one), than do it dry and save the stone powder. You can use that powder with a cloth and little water to clean the blade from the patina. Since the stone poweder does not etche the blade you will not harm the edge doing so.

But the best would probably be to let natural patina form over time and once it settles the knife will be less reactive (in particular the cladding).