Remove KU and refinish with cloudy finish?

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CiderBear

CiderBear

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Hi all,

A couple days ago I got a one off Watanabe iron clad Nakiri in white steel. The cladding is very reactive - this is what it looks like after 3 meals

JsQxv3k.jpg

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However, I'm not into the KU finish on this - it's very blotchy, and completely different from the KU on his Wat Pro nakiri in Blue steel.

I would like to remove the KU finish, and if possible refinish the entire blade in a finish similar to the part that already has patina - I'm guessing this is called a kasumi finish?

I currently have a Gesshin 1000/6000 combo stone, and some wet sandpaper.

I would be grateful if you experts could chime in on how I should go about doing this. Some fine folks have given me advice on the "Show your newest knife buy" threads, but I didn't want to clog that thread with follow up questions, so I thought I would make a separate thread here.

Some bonus questions:
1) Any idea why the KU finish is so blotchy on this knife? There are patches of KU in blue color, so I'm not sure if this is related to the KU process or what.
2) Anyone has advice on how to polish the horn ferrule? It has a sweet half blonde half black ferrule, but it doesn't look as nicely polished as the horn ferrules on my Kochi and Hinoura.

Thank you!
 
I personally think that the post kurochi finish looks like crap whenever I've seen it done. But some folks like it. IIRC it's a matter of some BKF and some scrubbing to get it off. Maybe some sandpaper for the reluctant bits.

And. Any potential resale value will go down the tubes. Perhaps press the Easy button and move it along as is?
 
I don’t get it. What’s the reason a removed KU finish looks bad? Do people just not take it far enough? I mean, if you really wail on it eventually you’ll just have a polished finish, right?
 
ian said:
I don’t get it. What’s the reason a removed KU finish looks bad? Do people just not take it far enough? I mean, if you really wail on it eventually you’ll just have a polished finish, right?
Click to expand...

Yes and no... depends on the knife. KU can hide a multitude of sins. Removing it brings them to light. I tried on a Moritaka. I was happy with how it came out, but it took forever by hand (even with low grit) and then took forever to get looking nice enough. The KU hid file marks, a few deep pits, etc... these only became noticeable after the KU came off. Power tools would be easier.

Long story short, it won’t look identical to an iron-clad knife. I’m with DaveB—if it bothers you, sell it and try again.
 
Yes. Watanabe nakiri are already thin.
It will take ages, not sure the finish will be good looking and the knife will lose value.
I wouldn‘t do it.
 
Honestly, I bought the knife without intending to sell it anyway. Out of all my knives, this is probably the one I'm most comfortable experimenting with, hence the question.
 
i have done it before on a shigefusa KU. It takes a very long time and the end result is not as nice as you would like since the blade is likely not very flat and there are spots where you just can't get rid of (get to).
 
I think it looks cool the way it is. The evolution of the KU finish tells a story similar to the way the evolution of the patina does on the blade road.

I don't know the source of the cladding he used, but it could vary in quality and be non-homogenous so you get different colors across it? There's supposedly some type of blackening that Japanese bladesmiths use on KU finishes sometimes, but I don't know what that is, could be similar to cold bluing solution used on firearms which is known to be very prone to inconsistency and blotchiness.

Guessing it's as-forged, so when you try to sand it down, you'll reveal all the high and low spots and could take forever to get it even as everybody else suggested. If you have a friend with a sandblasting cabinet, that is probably the quickest way to remove all the KU.
 
I have a similar looking knife I bought at eBay for $10 and was wondering what made such an uneven KU finish. It's blackened by some sort of bluing liquid?

Anyway, KU knives tend to have uneven surface as well. It can be hell to polish it.
 
I‘m going to tackle the horn ferrule polishing question:
I use a dremel like tool with a felt brush and a beeswax based furniture polish for this. This combination takes the ferrule to high gloss polish in no time.
I guess this will also work by hand with a clean cloth but will take some serious rubbing to accomplish.
 
Here are two attempts I have worked on that had badly damaged kurouchi finishes. I don't have before pictures. I already did quite a bit of work on them to get them to this state of presentability. To make them "pretty" would require a lot more.

The first is a santoku. I used a dremel with some kind of little attachment I don't remember but you can see the marks it leaves if you look close. I smoothed it over a bit with sandpaper and then did the bevel polishing with stones. It had a hammered texture underneath the kurouchi. This was also my first wa handle attempt. Horn ferrule with curly maple.

IMG_20190705_082541.jpg


Here's a Chinese cleaver. This one is all sandpaper. I put this handle on it (spalted sycamore) and then decided a year or two later that I wanted to remove the finish and redo it. It made gettting rid of the kurouchi near the bolster very difficult. I left it pretty rustic. I wish I had before pictures.

IMG_20190802_080605.jpg


Anyways, it's your knife. Do what you want to it. Have fun. Be safe. Show us pictures.
 
Thank you all again for your help. I was under the assumption that KU finish on top of nashiji finish would be difficult to work on (like @stringer's 2 knives), but a flat/ smooth KU finish like Watanabe or Shig might be better.

It seems like I was wrong - as @pkjames did with his Shig and @milkbaby suggested - what's underneath my KU finish my not be smooth. @childermass what was your experience with removing the KU from your Wat Standard nakiri? Were there obvious high/ low spots?

As you can see from the knife, there are "forging marks" (not sure what to call them) near the spine, around the kanji. If I do remove the finish, I will try to leave that part alone. Watanabe has some one-off knives he calls "gabi gyuto/ petite" that seem to have a polished blade except for the areas near the spine https://www.kitchen-knife.jp/special/damascuschefknife.htm[URL]https://www.kitchen-knife.jp/special/damascuschefknife.htm [/URL]- I'm wondering if he left the KU there for the same reason?
 
I've done a few. It's really hard to know what you find. Some were better than others for sure. There is so much work involved and I only did those due to some type of damage.
 
if you dont like it just grind it off. I suggest a small orbital sander. I have a small blue bosch. and it would eat that away in a few minutes. Or get a few sandpapers. probably gonna take a few hours to get to stringers look if doing this by hand unless its a smooth surface under there.
 
CiderBear said:
@childermass[/USER] what was your experience with removing the KU from your Wat Standard nakiri? Were there obvious high/ low spots?
Click to expand...

The Kurouchi on this particular knife sanded off very easy, it just took a few minutes to get rid of it. The surface of the blade was nowhere near even though. It had something more like a Nasiji look as with stringer's blades, just not that pronounced, plus some hammer marks. The Nashiji effect is due to lots of small pores in the cladding and it's almost impossible to get the Kurouchi out of those. As I liked the way it looked I left it this way and sanded it finer to make it look nicer. Evening out everything to achieve a smoooth and somewhat polished finish would have taken very long and would have meant to sacrifice a lot of material.
If you are fine with a little rustic look, it would be worth a try to see what's underneath the Kurouchi. Unfortunately this can't be reversed and as daveb and nutmeg already mentioned will have an impact on the resale value of the knife.
 
Ku finishes seem to wear off eventually w regular use.
Unless the knife is precious, why not move in that direction to clean things up?
Wabi Sabi.

Here are a few from my kitchen w ku removed.
The gyutos came used w ku partially gone, and I simply cleaned them further.
The others I hit w the stones, sandpaper, etc., leaving just enough for that rustic look.
Never looked back. They all slide through food w less drag now too.
Looks are subjective, right?


upload_2019-8-7_11-58-35.png
 
Third from left is Yamashin funayuki.
Fifth from left is Matsubara B2, one of my favorite knives.
Makes me laugh when I hear folks disparage small knives.
These 2 fly.
 
It's natural the KU should be uneven surface because it's typically forge scale from forging and heat treatment (dark oxides that form on the surface). Some western knifemakers think it's ugly and a shortcut because the bladesmith doesn't take the time to grind the entire blade to a consistent surface and finish, and it's true a KU knife is usually just forged and the bevels ground without extensively evening out the surface. Compare that to a Konosuke Fujiyama where the entire surface has been meticulously finished leaving no traces that it was ever forged (except for the wavy lamination line on the clad knives).

The problem with forging is that you can easily have a hammer strike that goes deeper than intended. Then when you try to grind everything even, the low spot will be too low, i.e. if you try to grind it out, then the knife will get too thin, so then you just leave it.
 
Here’s a Takeda “Yanagi” with removed KU. I kinda like it! My opinion for utility purposes: it seems silly to tiptoe around preserving a finish as if the tool were BNIB. But I’m way more favoring of the performance end of the performance vs presentation spectrum. Obviously there’s risk of imperfection revelation when a KU is removed (I think that’s part of what KU is all about), but I see the imperfections as birthmarks of the knife.
777E1337-1429-47A3-9B6D-4F88606B8D7D.jpeg 00F16ABE-ED7D-47AC-A340-6AB712B2E5AC.jpeg 6BB3BAC5-321F-4E52-B34E-20D166CA5CD9.jpeg
 
I'm pretty sure a nashiji finish is a KU that has been media blasted by the finisher. Most of the readily available nashiji finished knives are stainless clad, but you could try that if you wanted. This way, the low spots won't matter and will be blasted clean. Keep in mind it will readily patina.
 
SilverSwarfer said:
Here’s a Takeda “Yanagi” with removed KU. I kinda like it! My opinion for utility purposes: it seems silly to tiptoe around preserving a finish as if the tool were BNIB. But I’m way more favoring of the performance end of the performance vs presentation spectrum. Obviously there’s risk of imperfection revelation when a KU is removed (I think that’s part of what KU is all about), but I see the imperfections as birthmarks of the knife.
View attachment 58632 View attachment 58633 View attachment 58634
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I really like the look of that!
 
Thanks for the feedback. This is actually the easiest maintenance knife I have ever had, in terms of keeping it looking good. Surface texture automatically eliminates worries about scuffs or stains. When it’s time to polish, I can be as aggressive as I want since scratch patterns are totally obscured.
 
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