u/Slow-Highlight250

Knife: Mazaki 270 w2

Lads and ladies of the sub. I present to you my folly and my attempt to fix it.

This weekend I set out to refresh the kasumi I had put on this knife 9 months ago. That Kasumi had finished at a cerax 1k. A muddy stone I have had my best results with. I just wanted to crisp up the kasumi so o thought I would just start out at the 1k again.

That was either my first mistake or I just did a shit job at it. My scratch patter seemed even but definitely sitting on top of my older kasumi finish. I was running out of time for the project so I figured I would revisit it another day.

I have used flitz metal polish to remove the patina from this knife a few times just to let it re-patina so I thought maybe I’ll just give the whole knife a polish with that and see how it affects my shit kasumi.

It gave the knife a uniform look but was pretty un-remarkable. I cleaned it throughly and immediately went into a very large meal prep with it. Lots of veggies and a few acidic ingredients. I was constantly wiping down the blade and a new patina formed immediately. Mostly brown with some greenish blues and other colors. I figured I would revisit-try my polishing another day.

The knife was stored dry in a knife rack.

The next day my patina looked suspiciously more orange but nothing came off on a paper towel and I had diced like 5 onions with it immediately after resetting the patina.

Then today we have this, full blown rust formation.

I assume the flitz application into immediate use and then drying but not oiling allowed the somewhat humid air temp to create an environment where rust can form quickly on a highly reactive knife. I don’t have this problem on any other knife but this is the most reactive knife I own.

So this evening I set to the task of atonement for my ignorance.

I started by using an old cork and rubbing with some mineral oil and that removed most of the rust but not all.

Then I progressed to cork and baking side and that pretty much did the trick. However now my migaki finish was rather streaky.

Since I was in the weeds I went ahead and set to work on re-doing my kasumi.

I started on a naniwa 400 and got a very neat scratch pattern.

Jumped up to my cerax 1k and it was looking descent.

I have a suhiro 5k stone I never use so i though I would try it out. I’m not sure if it was user error but I hated how it looked.

So I went back to the 400 and then to the 1k again.

Now the kasumi was ok. Not my best and not great but I was ready to move on. However I now had 2 scuff marks near the spine of the knife. The area above the Shinogi was also still a little streaky from the rust removal.

I set about the process of very carefully using 1500,2000,2500 grit sandpaper to brush down the top half of the knife. This was the part I was petrified of. I have never tried any polishing above the Shinogi and was sure I would screw the 2 tone finish.

However it wound up working out and the scuff marks are masked now.

Gave it a slight polish with flitz, washed the heck out of it then dried and oiled it.

Will let it ride for a little bit until I can stick it in a roast to start my next round of patina responsibly.

Pictures are crap because there is no natural light and the Kasumi isn’t great but overall km pretty happy with the progress made tonight. I’m glad I wasn’t to cowardly to put my favorite knife to the stones in order to fix things.

Hello TCK hove mind.

I come to the elders with a small question on polishing.

This is my mazaki 270 W2 and it is my most used and favorite knife.

I put this kasumi on the knife about 9 months ago. I’m most likely going to refresh that Kasumi this weekend. I will most likely just use my muddy cerax 1k stone for that.

My question is on polishing the knife above the Shinogi line. I have used some flitz metal polish to reset the patina above the Shinogi line a few times.

A few scratches and streaks were revealed. What is my best option for maintaining the finish above the Shinogi line? I’m concerned a rust eraser might be too much and leave deep scratches. I assume the answer might be nagura stones? I don’t have any experience with those.

Odds are I will just hit it with some flitz after resetting my kasumi and enjoying regardless but I’m curious on other options.

Ok this feels like a dumb question but I am not coming up with a satisfactory answer. Please educate me.

I have and love several carbon steel knives that are made in San-mai construction. So carbon steel clad and carbon core steel.

I have seen carbon core knives that are stainless clad

I have several full stainless knives like this tetsujin kasumi.

Now my assumption is that knives with a hamon line are clad knives. And that this tetsujin is ginsan core and clad in stainless because the stainless cladding is less expensive than the ginsan core, the traditional knife making tradition is San mai and there are probably many other factors. If I am wrong here please correct me.

Now my question is: how come we never see a stainless core with carbon cladding? I assume it would look silly and why bother with a stainless core steel when you’re going to have the maintenance of a carbon cladding knife. But is there more to the reasoning?