Sharpening Stones - Soaking vs Splash'nGo - Some Info

Resinoid based stones respond to soaking and drying differently from ceramic, clay based, and magnesia based stones. Magnesia based stones, like the chocera, will crack when over-soaked due to magnesia (the binding agent) leaching out in the water. After a while, the stone looses structural stability. Clay based and ceramic stones do not have any cracking problems unless dropped (or sometimes when they are worn thin and you exert too much pressure in an unsupported section). Vitrified stones work in a similar way to the ceramic and clay based stones, but are often less firm and can break more easily when dropped and/or worn too thin. Resinoid based stones, like the gesshin 6000, arashiyama, kitayama, and even some of maxim's stones, respond to soaking differently. The soaking is actually not the issue at all. Soaking helps soften the stone, causing it to release more abrasive more quickly, improving tactile feedback, and helping create more mud. However, repeated soaking and drying, drying too quickly, or changes in humidity based on environment cause the stone to dry out unevenly. Because resinoid based stones are not as porous, air can not penetrate as quickly, nor can water escape in the same way. As water leaves the outer portion of the stone, the loss of mass causes the outside of the stone to shrink faster than the inside of the stone, which is the main cause of cracking with stones like this. Therefore, when it comes to resinoid based stones, you need to pick one of the following ways of dealing with them:
-soak permanently
-use as a splash and go stone
-soak and dry, but dry very carefully and slowly, while paying attention to general humidity

I got today from you a Naniwa Professional stone 400 and I want to know if we need to soak it permanently, for several hours, or 15 minutes (I heard all of the above on the web…). I also have a stone that I bought in Tokyo in a professional shop many years ago, it is 2 sided (one side is thicker and brown and 1000 grit and the other side is pink and thinner, 6000 grit) but I have no idea what brand it is (kenji only) ?? What should be the best way to address soaking?

My second question is about flattening my stone ? I know now that I will use this 400 that I just received to flatten my 1000 and my 6000 but what can I use to flatten my 400 ? is there a simple tool, trick?

While we are here, my third question is : I got beautiful Haruyuki Kasumi-Uchi Gyuto (210 mm) today, it is very nice. I understand that the bevels are 50-50 like European knifes. But what angle should I use to sharpen it? I heard somewhere that German or European blades (I have some nice Enckel chef knives) should be sharpened at an angle close to 20 degrees? And Japanese knives rather close to 15 degrees? Is that so? Does this applies to my new Gyuto?

Thanks for your attention!

the naniwa professional is a magnesia based stone and should not be soaked, as the binding agent will leach out if soaked. However, many like the feel of the stone after soaking. That being said, soaking would be a mistake.

As for the combo stone, a picture might help me know what stone it is.

For flattening, try using the 3 stone method for flattening. I.e. flatten stone a and b together, than a and c together, and finally stone b with stone c.

As for the angle of sharpening, you will want to be somewhere in the 10-15 degree range per side.

Hope this helps.

Thanks for your quick answer, of course it helps!!
I looked at my japanese stone and actually it is a KING... fairly well-known...
I thought there was only Kenji on it, but here it is...
What about soaking or not?

The 3 stone method cannot apply that is why I was asking for advice because my King is a DOUBLE-SIDED 1000/6000.
Therefore I only have 2 stones... now

Naniwa 400
King 1000/6000

how should I go about flattening?


thanks!

JEFX said:

Thanks for your quick answer, of course it helps!!
I looked at my japanese stone and actually it is a KING... fairly well-known...
I thought there was only Kenji on it, but here it is...
What about soaking or not?

The 3 stone method cannot apply that is why I was asking for advice because my King is a DOUBLE-SIDED 1000/6000.
Therefore I only have 2 stones... now

Naniwa 400
King 1000/6000

how should I go about flattening?


thanks!

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king makes a number of different stones... do you know which one you have? Again, a picture might help here.

Why not use something like sandpaper for flattening? I think i cover that in the stone flattening video i have here:
[video=youtube;ZFahNJEkTGg]https://www.youtube.com/watch?v=ZFahNJEkTGg&list=PLEBF55079F53216AB&index=18[/video]

here it is

sorry I realize that I cannot attach an image?
Can you tell me how (I dont see the little attach file icon?)

image hosting is your best bet

ok here is my first try, tell me if it worked

no dice yet... try something like facebook (publicly shared images) or imageshack

If you can't see it in "preview", no one else can see it either. Dropbox works for me. Some help available in "support forum"

let me make another try:

still didnt work... the link should have been this:
https://i.imgur.com/rAWvUvg.jpg

like this:


and soaking stone is the answer... well technically, the red side should be soaked and the tan size is a resinoid based splash and go stone, but both sides can be soaked... just make sure to dry the tan side as slowly as possible (wrapping with a damp towel helps)

Thanks for the info!!

I found in IMGUR where to look for the right DIRECT LINK, thanks for your patience!
One has to click on the photo and it gives you a popup window with all the links on the righthand side
I guess the one I should use is DIRECT LINK.
I just learned thanks!
I just dont understand why you have https:// and they give http:// ?

Hi again,
I just watched your flattening stones video and it is very informative and well-done thanks!
Unfortunately, you dont talk about sand paper in it, what do you recommend for me to flatten my 400 Naniwa?
thanks again in advance!

I'm thinking of moving from a King 1k/6k combo to gesshin stones. The 3 gesshin stone set is attractive but are soaking stones. I dont mind soaking for 15 minutes, but I am questioning the proper drying aspect. Would it be ok if I wrapped each stone in a damp cloth towel and put in an uncovered plastic tub to dry? Or is there more to it than that?

The 3 stones we have in the set are not hard to deal with... no wrapping... just take em out of water and leave em until they're dry. Heck, you can even stick them in the oven at a low temp if you want. They're ceramic stones... they'll be fine. The splash and go set is different though.

JBroida said:

The 3 stones we have in the set are not hard to deal with... no wrapping... just take em out of water and leave em until they're dry. Heck, you can even stick them in the oven at a low temp if you want. They're ceramic stones... they'll be fine. The splash and go set is different though.

Click to expand...

Great news. Thanks.

I thought resinoid stones couldn't be permasoaked. The Superstones by Naniwa are resinoid and are splash and go, but they could be permasoak too? I thought they would fall apart like the choseras, though I know the choseras are magnesia.

ABranson said:

I thought resinoid stones couldn't be permasoaked. The Superstones by Naniwa are resinoid and are splash and go, but they could be permasoak too? I thought they would fall apart like the choseras, though I know the choseras are magnesia.

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i wouldnt recommend soaking them, but you can. They are already soft and get really soft when soaked. Its not great for them.

Got ya. So some resinoids can be soaked indefinitely, just not good for these guys?

my 2 Cents:
I find 95% of Ohira Uchigumori hazuya (yes JNATS!) give better results when soaked 15-30 minutes depending on the size of the stone in fresh water before use.
That way the slurry breaks down much later.
I've hardly never met other Jnats that take benefit of soaking. Eventually a soft Maruo Yama Shiro Suita but these stones are very agressive and don't need much tricks to work efficiently.

In my experience of maybe 4-500 Jnats none broke oder cracked, even used in hardcore condition so, soaking is not risky at all.

nutmeg said:

In my experience of maybe 4-500 Jnats none broke oder cracked, even used in hardcore condition so, soaking is not risky at all.

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What about a red aoto? Do you think there could be any risks to it with soaking, or even a permasoak? My aoto is so thirsty. It seems like the stone might have some improvement if soaked.

What about silicon carbide stones? Whats the difference between synthetic stones and silicon carbide?

Silicon Carbide is just a type of abrasive used in sharpening stones. Aluminum Oxide is also a common abrasive used.

M1k3 said:

Silicon Carbide is just a type of abrasive used in sharpening stones. Aluminum Oxide is also a common abrasive used.

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Yeah I meant these kind of stones. Can we use these just like other synthetics?

julius777 said:

Yeah I meant these kind of stones. Can we use these just like other synthetics?View attachment 101933

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Yes you can. They feel like death in use though. Especially those, quite coarse.

M1k3 said:

Yes you can. They feel like death in use though. Especially those, quite coarse.

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Thanks. Best for those cheap stainless steel knives then

"Best" does not apply.

daveb said:

"Best" does not apply.

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I was going to give you a thumbs up, but I can't seem to find it for some reason.... that weird.