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T85

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hello my fellow knives enthusiast! I have a couple of honyaki sujihiki and yanagiba that I want to mirror polish. I have no idea of to do it. Can some body here tell me how to do it? What would I need? Any answers or links would be helpful, thanks guys.
 

M1k3

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I've done mirror polishing before. It was very satisfying. That said, I'd only do it again if I was paid a decent amount to do it.
 

Garner Harrison

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If no one minds I could also do with some help with polishing, just got my Mazaki knife and I want to know more about how to polish it properly. Without scratching the Hira/Tsura and messing up the Shinogi line.
 

T85

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What sort of finish are you starting from?
I want to start with my 1095 honyaki sujihiki. It’s has a nice patina right now, so I guess the first step would be to remove the patina, but I don’t know what the best way to do it as I’m also new to this
 

T85

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If no one minds I could also do with some help with polishing, just got my Mazaki knife and I want to know more about how to polish it properly. Without scratching the Hira/Tsura and messing up the Shinogi line.
Jump right in bro! This rabbit hole is wide
 

ian

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I want to start with my 1095 honyaki sujihiki. It’s has a nice patina right now, so I guess the first step would be to remove the patina, but I don’t know what the best way to do it as I’m also new to this
The patina will come off no matter what if you’re going to start polishing. If you want to take it off without changing the existing finish much, use flitz or simichrome or another metal polish. But don’t bother if you’re then going to polish it.

I’ve only ever tried to mirror polish something with sandpaper, which works, but is a huge pain. You just start at a low grit and go higher and higher till you can’t see scratches. It helps if you alternate the direction of movement when you switch grits so you can verify that you have removed the previous scratches. I was only doing a 135 mm petty... I wish you luck on your yanagiba....

Probably most will say that to preserve the crisp shinogi on your yanagiba you should at least use sandpaper attached to a hard, flat backing, or preferably use stones instead. I’ll let them tell you that, though. I have no real experience here.
 

Dendrobatez

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If you're looking to go the sandpaper route for this then Nick Wheeler videos are a good place to start for hand sanding technique.
I agree with @M1k3 though, in that it's a long process and would have to be something special for me to take it to a mirror.
 

gman

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i'm don't have a ton of experience, but the couple of knives i've polished so far i did entirely on stones, and using that method, the first thing you will discover is whether the grind has high and low spots. probably start with a medium grit and you will find out pretty quickly if there are spots where a flat stone just can't reach. from there decide whether you want to go to the effort of dropping down to a course grit stone to flatten the bevel, or if you want to switch to sandpaper. i believe you can keep a crisper shinogi if you stick with nice flat stones, but it will be a lot more work.
 

Garner Harrison

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Sorry if it seems like I'm trying to hijack the thread but I really want some advice on polishing my new knife and I think the advice I get could also help out T85. :D

Ive attached some pictures of the knife for reference. The blade is sharpened via the hamaguri technique from the store and I know how to maintain that thanks to Jon's videos, but the source of my trouble is the tip section and the "fake" shinogi line. The shinogi line is like others have said in other threads, there and is not there at the same time as it is rounded. Ive talked to others about this and so far I'm towards removing the near mirror polish on the hira if it seems like I cant maintain it since I plan on getting finger stones later.

The finish I'm going for is a kasumi finish, so I want to mainly focus on that and Im wondering if I just do hamaguri sharpening would it be likely I start to mess with the unique shinogi line. Another question would be if I do sharpening it would I eventually end up with a harder shinogi line if I do not round it while sharpening? I wont try and make this happen as I dont plan on removing that much material just for aesthetic. Finally is there any videos, tips and other threads I have missed that would help me with polishing/sharpening the tip section of this knife? Specifically this style bevel towards the tip, as I'm a very unsure about it (e.g. where to apply pressure and how to hamaguri sharpen it).

Thanks in advance to whoever responds! And I hope T85 also gets some nice help out of this :D
 

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T85

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i'm don't have a ton of experience, but the couple of knives i've polished so far i did entirely on stones, and using that method, the first thing you will discover is whether the grind has high and low spots. probably start with a medium grit and you will find out pretty quickly if there are spots where a flat stone just can't reach. from there decide whether you want to go to the effort of dropping down to a course grit stone to flatten the bevel, or if you want to switch to sandpaper. i believe you can keep a crisper shinogi if you stick with nice flat stones, but it will be a lot more work.
Thanks. I highest grit stone that I have now is 6000. Do I need a higher grit? Perhaps buying super high grit sand paper is cheapest way, but I do want to nice shinogi to stick out
 

M1k3

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Use a stiff backing on the sandpaper. Cork, piece of wood, rubber block, etc.
 
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T85

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If you're looking to go the sandpaper route for this then Nick Wheeler videos are a good place to start for hand sanding technique.
I agree with @M1k3 though, in that it's a long process and would have to be something special for me to take it to a mirror.
I’m definitely going to watch those videos tomorrow!
 

T85

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So How many hours (average) would it take to take 270mm to a mirror polish?
 

Alder26

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It takes longer as the grits get higher. But as an example it took me 2 hours to do a 1000 grit polish on one side of my watanabe
 

Dendrobatez

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4 hours for a 240mm k tip like this, key is to make sure you get all of those lower grit scratches out - a lot of times you wont see them again until you hit 2k grit. If it's pretty reactive like this mazaki itll get a fairly smooth patina real quick.

IMG_20180410_122849.jpg

IMG_20180429_192717.jpg
 

nutmeg

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I want to start with my 1095 honyaki sujihiki. It’s has a nice patina right now, so I guess the first step would be to remove the patina, but I don’t know what the best way to do it as I’m also new to this
Mirror on honyaki is hardcore.
The problem is the surface. One may believe the core on his clad knife is mega clean but put on a larger surface like a honyaki, every single scratch will appear at many angles of view. You may have seen pictures here and there on Instagram and you thought it's clean but in reality it's scratchy.
(I'm not saying all the mirror on any honyaki you've seen look lazy and ugly in real but more than you think)
And a clean mirror to maintain is challenging if you want to use the knife.

I don't know what grit/stone I would use. Generally above 3k the surface began to look scratchy so I finished cleanly on soft Uchigumori.
I tried high grit synth, some other very fine Jnats.. never got a clean surface.
Also, using stones means that the geometry is perfect, without any low spots and this doesn't exist, even on very expensive knives.

If I had to do the job, I would do it only with buffer wheel and try to keep in mind that scratches- even large are not such a big problem.
 

nutmeg

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So How many hours (average) would it take to take 270mm to a mirror polish?
The time depends on your strategy and on how flexible your mind is with cleanness and mirror intensity.
Admitting you have a full time job, you need sleep, eat etc.. and you don't have any buffer wheel or machine:
it's now 10:15 pm..
 
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gman

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a conservative estimate would be 2 hours per side, per grit. i have a 10 stone progression from extra extra course diamond to 12k synthetic, so that's 40 hours total, but i spread that over a few weeks. i'm sure there are faster ways to do it, but i enjoy the meditative process as much as the final result.

if you want to do the choil and spine too that would be all wet/dry sandpaper work, and best to do it first to avoid accidentally scratching the blade later.
 

pentryumf

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*chime*
I would echo Nutmeg, it took me close to 32 hrs to take a2 270 gyuto to near mirror, using 400 to 20000. A close to mirror is more than doable if you can put in the time.......a long time.
Optical fibre polishing pads to 0.1 micron will produce mirror, and would be absurd. Near mirror, sandpaper and patience, the last of my shinogi came out with okudo suita finger stones. It was a blast but I won't do it again.
 
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SilverSwarfer

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Here’s a Shi.han I sanded to “near mirror.” I put about 6hrs into this, using 800-1k-1.5k-3k sandpapers of various types. I wrapped some durable disposable foodservice towels around a 1” square wooden block about 3.5” long. I found that using some Autosol and adding some 3k SIC powder made the work go faster. As I progressed grits I went perpendicular to the last, always “pulling” with pressure (sanding pressure 1 direction only). Work was spread over about 3 weeks.

Pics aren’t great. Apologies. There is a pic showing original finish.
 

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da_mich*

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Honyaki? Sujihiki? Yanagiba? Mirror polish? :haironfire::haironfire::haironfire: That sounds very crazy. I know how to mirror polish a blade very fast and easy but i don´t tell you how to rape your Honyaki knife :haironfire::haironfire::haironfire:. I will not go to jail for aid to rape.
 
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