Best stones for polishing? Looking for my first "premium" polishing stones

[weeeeeeum]

For a long time I have been using semi cheap sharpening stones. They are of decent quality, coming from good brands but as I begin using more valuable knives I've been wanting something better for some time now. I have used cheap stones because stones in general are a gamble without knowing about them, thus this post.

I am looking for a better 5k/6k grit stone and a 8k/10k stone. I already have 2x 6k stones but both are somewhat on the cheap side and oftentimes leaves something to be desired. Specifically they are King S-1 6k and Imanishi Suita Rengen 6k (this one looks like vanilla and pepto bismol dippin dots pressed into an ice cream bar). They are very similar to each other in both feel and finish and both suffer the same problem

They do not handle large bevels very well and often become really sticky and form dry spots. During polishing the knife will begin to stick after 10 to 20 seconds and my finish becomes very streaky. I hate the feeling of my knife suddenly getting sucked into the stone and stuck. I especially have lots of problems with my Nakiri and its wide bevels and sometimes with my Yanagiba.

If possible I would really like a stone that has a very smooth consistent feel and perhaps less dense, like a soaking stone. I have a cerax 600 soaker and I love the feeling of this stone and how consistent it is, I have never had my knife stick, contrary to my splash and go's. It would also be preferable to have a nice kasumi finish with it.

I have heard of Arishiyama 6k and that it uses ground natural stones for its abrasive in a book, however have never seen the stone described in such way. I have also heard that it may be even worse when it comes to suction and I wonder if anyone has encountered that as well.

One last stone I would like is a step above 6k and around 8k/10k/12k. I would like to be able to get a mirror kasumi and also a stone that feels really nice without those sticking issues. I've been looking at the Kitiyama 8k because it seems to be very popular but I would also like to hear some personal feedback about it too, and whether or not it suffers from the issues I mentioned. Budget is $100-120 per stone, would be willing to go higher depending on value.

Thanks to everyone in advanced.

[atang]

Hello weeeum and welcome to the forum.

A brief checklist of some questions could help us clarify the causes of these symptoms.

Are your stones flat? Flattening gives the stone face a usable geometry for shaping and polishing. Dished stones will leave streaks.

Do you try soaking your 6k stones? A short soak could potentially slow down overly thirsty stones. Also raise some mud after flattening can help cushion the feeing of sticky stone. The use of a nagura can help reduce glazing if that something you’re experiencing.

Are the knife bevels flat? Wide bevels that have been flattened can create issues with suction against the stone. A wide bevel should have a slight convex shape. Blade performance will improve both polishing on stones and cutting ingredients.

What knives are you polishing? Some stones play better with certain steel types. Polishing stainless steels and cladding to a stone finish is a headache. More so if it’s Damascus.

Could you clarify what are your visual expectations from the final polish stage? Most metal can be brought to a near mirror finish using stones. However a kasumi finish will be hazy and misty. This will be evident on both the soft metal and the hard metal. Most synthetic stones will reveal contrast between the 2 metals. Again that is also dependent on the combination of metal compositions and stones used.

What stones are you currently using? Polishing could require a more extensive and involving game plan depending on what you want to see. Personally I think the Arishiyama is a nice stone.

I believe the issues you experienced can be reduced prior to buying a solution. As for polishing a knife, it may require more than a 1 stone replacement.

[weeeeeeum]

Thank you for your reply

My stones are very flat, I used a diamond plate and used a pencil to make sure they are completely flat.

I have tried giving them a brief soak. I'll pour some water on the surface and let it soak it for 10 or so minutes. While the stones don't absorb much they do seem slightly softer afterwards. I have used a nagura to build a pretty thick slurry and it helps to make the entire bevel very hazy, with little to no contrast on the hagane.

My knife bevels are also slightly convex. I work the knife a lot on my cerax 600 brick. I intentionally let the stone dish some and get some convex on my bevels. If you were to put a straight edge on them you would be able to see a hair's or less thickness of light on the edges.

My knives are all vintage so I do not know the steel other than "pretty hard carbon steel". I do have an Usuba that has Shirogami number one and my deba and yanigiba feel and look very similar after polishing. The yanagiba and usuba both have that stone sticking issue which makes me thinks its something to do with a wide bevel. Another problem could be the width and thickness of the hagane. The biggest issue I have is with my nakiri and most of the polishing bevel is the hagane. Additionally the steel of the nakiri does seem to be marginally softer.

The expectation I have from more premium and finer stones are a high level of contrast between the jigane and hagane. Each one having a fine finish in their own right. Additionally very consistent as well. So a very misty and hazy jigane and a very bright and mirror like hagane. My current finishing stones can leave a good consistent kasumi on some knives(I would like it to be finer however) But they struggle with wider bevels and that nakiri I mentioned. Additionally they can sometimes be inconsistent with streaks and sticking.

The stones I currently use are a Cerax 600 brick soaker, Naniwa Chosera 800 splash, king S-1 6k splash. I recognize I need a 2k/3k stone and I'm getting a naniwa green brick at the same time as a new polishing stone.

Some other stones I have and use are a Aoto Amakusa orange ~800 natural, a mystery chinese natural stone around ~5k, previously mentioned Imanishi Suite Rengen 6k splash (very similar to king 6k), Atoma 140 diamond plate and a (suehiro?) 800 grit diamond plate.

[ex1580]

Here is an interesting video about polishing:

[atang]

I saw the pics you posted of the knives you’re working on. They do appear to be flat in the bevel with the normal wear/sharpening patterns of more heavily used knives. Without the geometry corrections, they will tend to have the sticking/suction due to being flat against a flat stone. Very similar to what we experience when using a (non atoma) flattening plate to flatten the stone surface. You’ll have to break out that Atoma plate and correct blade profile, shinogi line, and the face geometry to free up the sticking on the yanagiba. The nakiri doesn’t look too bad. Allow the convex to exist not only from shinogi to edge but also slightly convex from heel to tip below the shinogi line. Hope that makes sense.

When you get to the polishing stages try using shorter strokes with extremely light pressure as if you’re trying to float the knife on the mud without contacting the stone. Almost impossible task, though that’s the mental goal to alleviate the sticking. Don’t use too much water as this inhibits the mud’s ability to hydroplane.

You’re correct that you’ll need a stone to refine the scratches such as the green brick. An additional pre-polisher such as a 4k would help before moving to the 6k on up to 8k/10k+. The green brick would be a great option though the sticking will still be present; particularly so with the green brick. It’s a great stone. But I too have experienced sticking while working flatter bevels on that one. A very muddy stone, easy to gouge even on smaller angle errors. Pressure control, water control, and patience are needed to reach the green brick’s full potential.

Before I get into any stone recommendations the contrast of a hazy jigane and a crystal mirror reflective hagane off one single final stone is asking a lot. Higher contrast on jigane can come from a soft medium grit stone such as the green brick or a natural arato or soft nakado. A highly reflective mirror on hagane can be less painstakingly achieved with sub micron diamond polishing medium. If you’re looking for something similar to a fresh factory finish, sorry to say it’s going to be a lot of work without the machines to create the blasted finish of a brand new knife. Personally I may attempt it using finger polishing on only the hagane just like on antique nihonto or Japanese swords. Naturals can give you some of the best polishing results though the natural kasumi polish will create hagane that is highly reflective and white. Not the crystal clear mirror you may be seeking. If you’re interested in an acid etch approach that’s possible as well. Bear in mind that the finer the particle size, the jigane will also become more shiny as working the entire blade road as one surface may still result in the streaking you’re experiencing. Apologies that may have been overly long winded. Hope I didn’t lose you there.

I feel you may at least get close to what you’re looking for as far as sharpening enjoyment and aesthetic quality if you are able to fill some of the gaps in the stones you mentioned in order to tighten up the progression. This could take 2-3 synthetics and a natural pre-finish or final finish stone. The chosera 800 is a great final shaping stone which makes for an easy anchor point to build a stone set that you can grow with but also not outgrow too fast.

Let me know what you think if this interests you and how far down the rabbit hole you’d like to go.

[weeeeeeum]

That's sort of the reality I was naively trying to avoid. Currently for my kasumi finish I build up a thick slurry on my 6k stone and float the knife on it. It makes the whole edge very misty and then I use a pencil eraser, a lint free makeup wipe and a dab of knife polishing paste. I scrub the hagane vigorously and it eventually gets pretty shiny. It would take an excruciatingly long time to get a perfect mirror though, currently I just get it shiny. I could also experiment with the inverse too. Get the whole bevel very shiny and make the jigane hazy. I have tried this before, using more paste, a drop more water and using just finger pressure with my fingertips instead of the pencil eraser.

I have somewhat thought of using a mild acid etch, with a patina there is a very high degree of contrast between the two steels on my nakiri. The Hagane is extremely reactive and becomes very colorful when cutting vegetables while the jigane appears more dull.

Regarding how "deep" I want to get into this stuff, its already up to my neck haha. In total I have 4 nakiris, 4 debas, 3 yanagiba, 2 kiritsukes, 2 usubas and half a dozen kanna blades, a dozen or two chisels and other wood working tools. Most of my collection is yet to be restored and I plan to either sell or gift many of them. I bought most of them because I find a ton of high quality and handforged blades being sold for cheap and it feels blasphemous that these are languishing and soon going to be thrown out after the listing gets too old. Additionally I've noticed them getting more and more expensive as time goes on. I got a beautiful hand forged heavy hon deba for 20$ and now from the same and similar sellers its around $60. So I've carefully been picking out really nice blades for cheap. I bought my whole knife collection for around $500 which is pretty damn incredible considering they are handforged and extremely well made (they often have extremely clean ura's, hand engraved kanji and buffalo horn handles).

This was also why I was preparing to invest in some new stones, in the last week I got the green brick 2k, imanishi 220, morihei hishiboshi 9k. I am also preparing to find a well suited belt sander for the agonizing amount of thinning that awaits me.

[atang]

That's sort of the reality I was naively trying to avoid. Currently for my kasumi finish I build up a thick slurry on my 6k stone and float the knife on it. It makes the whole edge very misty and then I use a pencil eraser, a lint free makeup wipe and a dab of knife polishing paste. I scrub the hagane vigorously and it eventually gets pretty shiny. It would take an excruciatingly long time to get a perfect mirror though, currently I just get it shiny. I could also experiment with the inverse too. Get the whole bevel very shiny and make the jigane hazy. I have tried this before, using more paste, a drop more water and using just finger pressure with my fingertips instead of the pencil eraser.

I have somewhat thought of using a mild acid etch, with a patina there is a very high degree of contrast between the two steels on my nakiri. The Hagane is extremely reactive and becomes very colorful when cutting vegetables while the jigane appears more dull.

Regarding how "deep" I want to get into this stuff, its already up to my neck haha. In total I have 4 nakiris, 4 debas, 3 yanagiba, 2 kiritsukes, 2 usubas and half a dozen kanna blades, a dozen or two chisels and other wood working tools. Most of my collection is yet to be restored and I plan to either sell or gift many of them. I bought most of them because I find a ton of high quality and handforged blades being sold for cheap and it feels blasphemous that these are languishing and soon going to be thrown out after the listing gets too old. Additionally I've noticed them getting more and more expensive as time goes on. I got a beautiful hand forged heavy hon deba for 20$ and now from the same and similar sellers its around $60. So I've carefully been picking out really nice blades for cheap. I bought my whole knife collection for around $500 which is pretty damn incredible considering they are handforged and extremely well made (they often have extremely clean ura's, hand engraved kanji and buffalo horn handles).

This was also why I was preparing to invest in some new stones, in the last week I got the green brick 2k, imanishi 220, morihei hishiboshi 9k. I am also preparing to find a well suited belt sander for the agonizing amount of thinning that awaits me.

That’s superb. Always a good feeling to give those old pieces a second life I second the clean ura

I think you’ll like the green brick. IME 15+ minute surface hydration gets the mud going a little faster.

[weeeeeeum]

Also as an update and goofing around with the stone again. I have noticed that the longer I use the stone the more water it will absorb. I initially observed this during use and I would look at the side of the stone and see that the upper 1/3 of the surface was visibly hydrated. After noticing this I tried giving it a 10 minute, full submersion, soak. It was still kind of sticky so I gave it another 10 mins (total 20). After that it behaved a lot better.

I never have tried this because while researching the stone a store was very adamant "DO NOT SOAK THE STONE". Because of that I was very hesitant to give it a proper soak. That being said it does still occasionally stick and streak but it is remarkably more well behaved than before.

[atang]

That’s great the stone is becoming more user friendly for you. As long as you let it completely dry after use to prevent it from falling apart. The stone won’t be able to sustain long term moisture and will likely crack and crumble or even warp. Give it at least 3-4 days between uses especially when you decide to saturate it more than usual. I only have one magnesia stone which I will ‘soak’ by submerging only the sharpening surface face down (~4mm) in water. Glad to hear your positive experience and observation.

[gladius]

Check out the Naniwa Super Stones <<. They are IMO the best synthetic stone for polishing. Follow with diamond on balsa strop << if you want to take it further.

[weeeeeeum]

Check out the Naniwa Super Stones <<. They are IMO the best synthetic stone for polishing. Follow with diamond on balsa strop << if you want to take it further.

I'll look into them but it could be a while because I have already made an order for some polishing stones. I do remember hearing that these give a much finer polish than the grit rating would suggest as they are loaded with polishing compounds. If I were to replace a "standard" 6k polishing stone would I get a 6k super stone or a 4k/3k stone to account for the greater polishing performance these stones offer?

I may also get one because I might need another stone between my 2k and 6k but we'll see once they arrive and I use them.

[gladius]

I'll look into them but it could be a while because I have already made an order for some polishing stones. I do remember hearing that these give a much finer polish than the grit rating would suggest as they are loaded with polishing compounds.

If I were to replace a "standard" 6k polishing stone would I get a 6k super stone or a 4k/3k stone to account for the greater polishing performance these stones offer?

I may also get one because I might need another stone between my 2k and 6k but we'll see once they arrive and I use them.

---
What polishing stones did you order?

Get either a 5k or 8k. I jump to a fine range from a 2k; most knives I finish at ~5k but some of the higher-end carbons I go to 8k or higher with compound or natural stones.

You may find you do not need a stone between your 2k (any brand) and 5k or 8k Super Stones.

[weeeeeeum]

A 220 pink imanishi brick, Naniwa 2k green brick of joy and a morihei hishiboshi 9k. I'll see if I will need a new 6k stone considering it is no longer my final polish stone.

My final progression would be 220 brick, cerax 600 soak, naniwa chosera p800 (more like 1200 grit), 2k naniwa green brick, King 6k or suita rengen 6k, morihei 9k.

[ex1580]

That's a bunch of stones! Just wait until you get a new knife in a different steel and it doesn't work as well. That's how I ended up with a bin full of stones, haha. Have you looked at the Arashiyama stones? I think for the money they are really nice, although I rarely use a 6k. I like a 1k, 4k, 8/9k progression because it seems to work on all of my knives, whereas the 6k is sometimes further than I want to go. You have different knives though.

[weeeeeeum]

That's a bunch of stones! Just wait until you get a new knife in a different steel and it doesn't work as well. That's how I ended up with a bin full of stones, haha. Have you looked at the Arashiyama stones? I think for the money they are really nice, although I rarely use a 6k. I like a 1k, 4k, 8/9k progression because it seems to work on all of my knives, whereas the 6k is sometimes further than I want to go. You have different knives though.

Yes I have looked at them and had a lot of interest because in a book I read the author mentioned that the grit particles are made of natural stones and that it may perform closely to one. Right now I'll wait to use my new stones if they will solve the issues I have been having, because I can get a consistent hazy finish on my 6k stones if I soak them and build a fat slurry. If I can get a good finish with my new 9k afterwards than I would not need another 6k stone.

I am very curious to see how my current stones will perform on HAP40, as I have a knife blank made out of it (still need to thin and polish it however).

[ex1580]

In case you didn't see the recent conversation about sharpening HAP40 I will leave this here: https://www.chefknivestogoforums.com/vi ... hp?t=17728

I think you can probably shape the blade with the stones you have but it might not be as fast. There is also some speculation that a diamond edge would be sharper, but you might be able to just strop it with diamonds at the end to get that. I would use Shapton Glass on a wide bevel HAP40 if I had to but would rather send it to someone with power tools. Wide bevel knives made of wear resistant steel make me think the knife maker is playing a mean joke on me.