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:
-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
how should I go about flattening?
king makes a number of different stones... do you know which one you have? Again, a picture might help here.
Originally Posted by JEFX
Why not use something like sandpaper for flattening? I think i cover that in the stone flattening video i have here:
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