kasumi, kurouchi, low carbon steel/iron

[olpappy]

Do most here keep their kasumi knives pristine or let them patina?

I have noted that many including myself have had problems with kurouchi cladding rusting. I am under the impression that the low carbon steel used to clad KU knives is close to or the same material used to form the soft layer of a kasumi knife, anyone know if this is right or wrong? I know some here have visited some of the manufacturers in Japan and seen knives being made, perhaps someone knows the answer. My assumption is that the only difference between a KU and a migaki knife is the finishing process, not the materials.

Right now I have KU blade which is rusted and the black is more than halfway gone. The surface itself is not terribly irregular, no really deep hammer marks. I am thinking of rubbing it on coarse and fine stones to make a migaki finish. If I do this it shouldn't be any harder to maintain than a kasumi type knife, should it?

 

[vicv]

Pretty much. The kurouchi is the forge scale being left on. Kasumi is the scale being ground off then polished

 

[ecrphoto]

Is it possible then to remove kurouchi with a diamond plate and turn it into a kasumi? Or is that just a great way to ruin a knife?

 

[Badgertooth]

It's doable. @nutmeg has done it with a Watanabe knife that came out amazingly.

 

[zetieum]

It's doable. @nutmeg has done it with a Watanabe knife that came out amazingly.

Doable fore sure! But one would better be skilled, patient and rather well equipped.
If I add to do smth like that for a a knife that is valuable: I would like it send it to a professional.

 

[K813zra]

I have never removed a KU finish so I will not be any help there. However, you asked who keeps their knives polished or lets them patina. I let my Kasumi knives patina and then clean them up every time they get a full sharpening. Kind of like a rinse and repeat sort of thing. Maybe I am just lucky but I have not had a KU knife rust. (Knock on wood.) I think if I wanted to keep my knife patina free I would just go with something stainless clad. I don't particularly care for orange and black onions. :lol2:

 

[LifeByA1000Cuts]

A fine stone won't usually do a migaki finish - you would most likely end up with all-over kasumi (blade face will look like blade road). And even that requires absolute flatness (nearly guaranteed not to be there. Make sure not to destroy an s grind that way!), which can turn out to be far more work than intended.

For Migaki-like, usually sandpaper (lot of work!) is recommended; see all what has been written on knife thinning and refinishing. BTW, authentic migaki (likely rare on a hocho) is a metal-on-metal polishing technique (no, haven't bothered trying it after all).

Hands off new/untested/cheap diamond stones for that - they can make out-of-grit scratches that will take you hours to grind out.


...


Usually grinding the blade road clean on any knife with a shinogi when doing full sharpening, not bothering with removing patina inside an urasuki, dealing with superficial rust on cladding with toothpaste.