Thread: Natural Japanese waterstones

Its not my fault. Something happened to me when I watched that flying kokeshi doll stool show

I'm obviously losing my grit on reality

Steve

"I do, I do like green rouge on ham"

OK. Seriously.

I have the following natural awase-do from Nakaoka-san: Shinden suita and Ozaki ShouhonzanShinso (Sogoro) Tomae. Both have toxic elements (good price).
Also two from LV Tools - one is Narutaki, can't remember the other (lost the label and ground off the stamps).

Also have an omura, binsui, aoto and iyoto. Plus natural nagura (from LV Tools a few years back).

I, on the other hand, am too addlepated to remember, ever, to make note of what I have: only think of it when I'm here.

But list forthcoming... I promise.

Steve -- so sorry about flying fotobuquet brain injury... feel free to contact my attorney at 1-(800)-NO WAY2.

B

I tried that number, but I was put on hold and told, although my call was valuable, I was number 47 in line. No way, I'm not that bad. Besides, I think the flying kokeshis might just take off and then you'll be too rich for me to litigate.

Steve

On the upside, the latest phones have voice recognition so I can still make calls in a straight jacket.

Hi Wilbur/Becky/Pam/Steve – Re particle size/number discussion.

I thought Wilbur’s graphic was very useful in illustrating the difference between synthetic and natural stones. The more I look at that graph in comparison with what I understand the more accurate I think it is, including the increased number of particles pre and post use.

I do, however, have a couple of qualifiers. Perhaps obvious, but worth stating, the ‘used natural stone’ line on the graph only represent the ‘free’ particles suspended in the slurry + , to a lesser extent, the particles in the very thin top surface layer of the stone. In relation to the latter, I think that the particles only partly break down in situ and are more likely to separate away from the body of the stone as larger particles before breaking down into smaller particles as they are worked in the slurry. If I am right about this last point it has implications for how we use natural stones.

Second point, pedantic I must admit, there must be some breakdown in particle size with synthetic stones but perhaps not significant enough to be represented on the graph or taken into account in our discussions.

Back to the increasing number of particles created with use - I am not sure that it’s anywhere near as important as the shift in grit size, but my two cents worth on that discussion is that if any particle is broken down into two or more smaller particles there has to be less of that size particle and twice the number, or more, smaller particles. If anything, the ‘after use’ line should peak many times higher than the before use line. We are not talking here about the stone as a whole (just the slurry + top micron or so of the stone) nor conservation of matter or volume, just how many particles there are in each grit size.

So, are there any advantages in the up-shift in grit size during use? Yes, if you start with a clean stone and want to go in one session from fine to superfine polish on the one stone. No, if you leave the slurry on the stone from last use and are not ready for the superfine polish stage.

If I am right about most of the breakdown in particle size occurring in the slurry phase then the initial creation of the slurry with a diamond plate should enhance this process.

Neil

Originally Posted by Sheets

On other tangents (worthy of entry to the loony bin no doubt*), can there be some chemical reaction because of the water? (other than straight oxidation - but even that on a near molecular scale must have an effect?)

Not sure about a chemical reaction, but the water does soften the bonding component of the matrix to release the harder grit particles. I think I am right in saying that this is what waterstones do. It's also the reason I don't store my natural stones in water.

On the mechanical process of particle release, I visual it more like a road grader running its blade over the surface of the stone rather than a road roller crushing down the particles of stone, although there is probably both effects. The grader drags out any large lose rocks from the road surface while those that remain embedded provide the most aggressive and long deep cuts. Once released, these particles are tumbled around in the slurry knocking against each other, the base stone and tool to progressively break down into smaller particles like they would in a pestle and mortar (changed metaphor ). In the 'free' state the grit particles are also less aggressive and create a different abrasion pattern as they tumble and slide between the tool and hard stone....maybe.

Neil

Originally Posted by NeilS

Second point, pedantic I must admit, there must be some breakdown in particle size with synthetic stones but perhaps not significant enough to be represented on the graph or taken into account in our discussions.

There were two reasons for my thinking this as I was working this through. First, to my understanding, the particles in the man-made stones were ceramic, as opposed to the natural waterstones, which are sedimentary in nature. Second, to my knowledge, no one has ever reported this feeling that the grit size gets smaller with use with any man-made stone. There are other man-made substances that do have this behavior, the most familiar of which to members of this forum is probably the use of carbide particles on a kanaban.

I have stones from many of the usual supliers, and am working with So-san currently (one of those indescribably fine stones that he has tucked away). I agree with pretty much everything that's been concluded thus far, excellent discussion!

I should say that the stones that I got from Nakaoka-san were a little disapointing as compared to the images he provides. They all work pretty well (Aoto, Iyoto, Narutaki), so I can't complain too much, but it should be noted that there are other supliers who have a more "user friendly" approach.

As for the nagura, I find that a good diamond plate accomplishes everything that the nagura does, without the problem of mixing grits. And on top pf that it keeps the stone flat as well, two birds with one stone... er... bad joke, sorry.

Originally Posted by wilburpan

There were two reasons for my thinking this as I was working this through. First, to my understanding, the particles in the man-made stones were ceramic, as opposed to the natural waterstones, which are sedimentary in nature. Second, to my knowledge, no one has ever reported this feeling that the grit size gets smaller with use with any man-made stone. There are other man-made substances that do have this behavior, the most familiar of which to members of this forum is probably the use of carbide particles on a kanaban.

Wilbur - It's not a major effect in man-made waterstones, nor worth much comment, but I believe it is there. I can think of two plane makers (Terry Gordon and Ron Hock) who recommend starving man-made waterstones of water to get a final finer polish on the blade. Here is a quote from the Hock notes:

"FINAL SMOOTHING. The second part of this process is to do a final smoothing on the 1000-grit stone. This is the same as the first step, just don't rinse the stone. Instead, let a "slurry" of particles collect on the surface of the stone as you hone.

This "slurry" is sort of a mud made up of broken fragments from the waterstone. Since these fragments are small, they produce a finer finish than working on a clean, freshly-rinsed waterstone." http://www.hocktools.com/sharpen2.htm

But, as I have said, it's a minor effect that that is worth noting but otherwise can be ignored in this discussion.

Neil

Originally Posted by yojimbo

...Does this mean we're dabbling in atom-splitting? Or is it just hair-splitting? Or maybe it's just my personality splitting: .

Becky (and whoever else is in here with me)

Yeah, I have a strong governor, too. I think it means we haven't sufficiently identified the issues. I prefer to think of stones as sedimentary, built from silt and compacted by more silt on top; therefore, all we can do is separate the silt, reverse the process.

Pam

These stones, while sedimentary in origin, are really much more changed than just their original, uncompacted/uncompressed material. Time (eons) and the great pressure of million tons of material piled up on top and tectonic shifting causing further pressure can morph stone into a form almost completely, if not completely (in many cases) different than the layers of genesis silt. Interaction between the elements (water of various degrees of ph, metals, air, climate, etc.) results in a molecular structure which, in our case (focussing on natural whetstone) can't simply return to its original state (not by mechanical means alone). So, no matter how small the particles of stone become as they get released from whatever structure cements them together, they are still, molecularly, unchanged.
Now, this brings me back to my point about the water. Added to the mix, does it make some sort of chemical soup with the constituents of the stone (and O2, CO2 in the air) and the steel (iron and carbon) which might cause a chemical (molecular) change which affects the steel, even if on a small scale?


Steve

Sheets, I can see that being somewhat valid.

The Japanese stones seem to have an affect thats similar to etching on steel (damascus patterns and general lamination lines are brought out) which would imply some kind of ph difference, but that would be easily measurable. I'll try to remember to litmus test the slurry from my stones next time I use them.

Could there be another reason the Japanese stones bring out lamination lines when man-made stones do not?

Originally Posted by Sheets

These stones, while sedimentary in origin,

..snip...
.
Now, this brings me back to my point about the water. Added to the mix, does it make some sort of chemical soup with the constituents of the stone (and O2, CO2 in the air) and the steel (iron and carbon) which might cause a chemical (molecular) change which affects the steel, even if on a small scale?

Steve - Not quite sure what affects you had in mind....like, make the steel rusty?... or did I miss that in one of your earlier posts?

On the sedimentary origins, as we know the composition of the stones vary widely depending on the mine and stratum. At the coarse end, stones are little more than sandstone, and at the other end are the fine finishing stones from deep strata comprising mainly quartz/silica shales (basically metamorphosised silt clays). Here are more details from So-san if anyone wants to follow up on that:

http://www.geocities.com/soatoz/tech...i/Awasedo.html

Casting my mind back to my days in ceramics, once a clay is fully metamorphosised(through pressure and/or heat) you can't reverse the process by just dissolving it again in water. From my limited experience of natural waterstones, it seems to me that the super-hard stones are fully metamorphosised and will remain that way even if you leave them in a bucket of water for all of eternity. On the other hand my softer stone feels like it has not fully metamorphosised...the bonds are weaker. The slurry forms quickly and feels a bit clay like (ie slippery) and I expect that it wouldn't take too kindly to being left in a bucket of water for any length of time. So, the particle breakdown is mainly mechanical but perhaps aided by the weakening of molecular bonds in water of some 'softer' stones.

Not sure if any of that is adding anything to anyone's thinking on the subject or just stating the bleating obvious.

Neil

Neil -- (and Sheets, Pam, Russell, Wilburpan) --

What you say makes sense (effects of storing coarse vs. fine stones in water), and clarifies (?) to me the fact that in that sedimentary rock you have layers of silt in differing phases of compression. I assume that the fine stones are from the deepest strata, and have gradually undergone such compaction that all air, larger inclusions, and even the minute pockets left between individual grains of silt have all been squeezed out through compaction.

The more coarse stones (the better of which have very few visible inclusions), still retain the open shape of the original, larger silt because they haven't be compacted as much. I have a zebra stone in which you can actually see the open structure (or, rather, I should say, get the impression of its open structure) when looking at a flattened face. It's quite aggressive, but breaks down fairly fast and needs flattening often -- sometimes, though rarely, during the course of correcting a single blade.

The thing is, I still can't make logic out of the thought that, aside from the massive compaction, the substance of the stone has changed at all -- assuming there's been no particular heat in the process.

So I'm kind of with Pam on this -- that what we are doing is basically returning the stone to its original silt-like state. After all, what is the slurry but a thickened silt soup? (Cue Steve for raging series of unappetizing puns.)

Am I missing something?

Originally Posted by yojimbo

The thing is, I still can't make logic out of the thought that, aside from the massive compaction, the substance of the stone has changed at all -- assuming there's been no particular heat in the process.

Becky

Yep, plenty of heat in the volcanic and tectonic (think earthquakes) geology of Japan.

Pressure + Heat = Irreversible Metamorphic Change in crystalline structure of sedimentary deposits, the heat being the most important factor in the process. The deeper the stratum the greater the heat and pressure and the more complete the metamorphic change.

Although the chemical composition of the sediments are retained, the mineral properties are irreversibly changed. Think of the chemical carbon, from which both soot and diamonds are made. Same chemical, different crystalline structures and minerals.

Hope that makes the process I was referring to clearer.

Neil