Ohishi vs Shapton Professional water stones

[Erich Weidner]

...They can't be stored in water, on the other hand, or they get quite soft. Frankly, my Norton stones are better behaved in this regard, but I like the Ohishi 10,000 grit stone for a final polish. The Nortons stay wet after a soaking and don't get too soft.

Is this a permanent condition? Or just until they dry out? I've certainly forgotten about them soaking and come back hours later. Stones seemed to work fine. If they are softer from a soak does that just mean they don't cut as well? Or the stone breaks down faster?

[Michael Bulatowicz]

Is this a permanent condition? Or just until they dry out? I've certainly forgotten about them soaking and come back hours later. Stones seemed to work fine. If they are softer from a soak does that just mean they don't cut as well? Or the stone breaks down faster?

According to what I have read, stones with a magnesia binder release grit in part by having the binder dissolve in water. This would imply that prolonged soaking of the stone (whatever “prolonged” means in this case) would dissolve a large quantity of the binder, making the stone break down quickly in use even after it dries out. I don’t know whether or not the Oishi stones fall into this category, I don’t have any Oishi stones, and I don't have any experience with magnesia-binder stones in general, so this is all based on reading and speculation. The product description says not to soak them, however, so I would guess (but don’t actually know) that soaking will slowly break them down.

Other bonding media break down more by mechanical means (the process of sharpening tools, for example) and are fine with being stored in water. My water stones stay wet for weeks or even months on end. I usually add water at least once a day so that they’re always ready to go when I have a chance to squeeze some woodworking into my day—they do better when saturated with water and I don’t want to have to wait to sharpen my tools. Two to three years of this (depending on the stone) and they have never had a problem, but I specifically purchased stones that are fine with staying in water at all times.

[George Yetka]

I have had the naniwa pros (1000,3000,5000) for 4 years now. The 10000 I got about 2 years ago. So far so good. Very nice to work with but the only thing i have to compare them too is the dmt diasharps and the crazy sharp system.

I also only bring them out every 4 months and sharpen everything. I mean everything. Chisels, planes, kitchen knives(good and bad ones), carry knives, anything any one is willing to bring over. So dont let me guide you

[Elise Anna Boer]

The Hibiki lines of stones made by Naniwa are my favourite. These are made specifically for tools and are very hard. The Hibiki stones release abrasive at a slow rate so they take a long time to develop a hollow. I especially like the 8000 stone because it feels so nice to sharpen on.