# Communities > Bladesmiths, Blacksmiths, Artisans and Professionals > Japanese-Style Sword Makers Cafe >  Water Stones

## Dan Pfanenstiel

How come my artificial 6000 grit stone just kind of smears with an oily kind of black film? Blade is clean. Tried nagura and without and same thing.

Dan

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## Joseph Renner

probably a lubricant I have some water stones that do that. 6000, isnt that more like burnishing than polishing.

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## Dan Pfanenstiel

Ya, dug out my water stones after a phone conversation with John D and all I got is 1500 grit and the 6000. Maybe the 6000 is too fine.

Dan

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## JohnD

> _Originally posted by Dan Pfanenstiel_ 
> *Ya, dug out my water stones after a phone conversation with John D and all I got is 1500 grit and the 6000. Maybe the 6000 is too fine.
> 
> Dan*


I wish I could help but I've never used water stones before. I'm hoping that you're not jumping from 1500-6000. The one I could think of happening is that you don't have enough slury on your stone. Another thing to consider is that, traditional polishing stones (may it be synthetic or natural) have a different shape of its particles. Their more rounded rather than sharp. So what's happening is that you're more like scrubbing the steel rather than scratching it.

Taking a blade this high could get very tricky specially if you don't have the right stone to match you're blade. Try adding more slury on your stone and use light preasure. Don't work the same spot on the stone all the time, spread it around and try to use the whole stone. 

Hope that helps.

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## Dan Pfanenstiel

waitaminute John, you don't use water stones? What'r you using?

I think going from 1500 to 6000 is probably bad, just playing with them. Just weird that the fine stone reacts the way it does.

Dan

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## JohnD

> _Originally posted by Dan Pfanenstiel_ 
> *waitaminute John, you don't use water stones? What'r you using?
> 
> I think going from 1500 to 6000 is probably bad, just playing with them. Just weird that the fine stone reacts the way it does.
> 
> Dan*


I use a combination of synthetic and natural stones from Japan. For synthetic, I use Asahi brand from kongo-do to kasei-do. I use Asahi Chu-nagura-do and Koma-nagura-do but I also use natural nagura-do depending on the blade that I'm polishing. From Uchigumori to hazuya and jizuya its all natural. 

I'm not sure exactly what kind/brand of warerstones you're using but if they are the kind that you could pick up at a place like Japan woodworker (for example) then they are different. These kinds or water stones are more for sharpening rather than polishing. While Japanese Polishing stones sharpen the edge as well, it does work differently than water stones. I hope that makes sense :Smilie:  

Let me know how it works for you ok Dan :Smilie: 

Cheers,

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## Dan Pfanenstiel

Think I got mine from Aquastone in the S.F. bay area. Box says "Suehiro sharpening stone" guess that explains it. Made in Japan though...

Dan

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## JohnD

> _Originally posted by Dan Pfanenstiel_ 
> *Think I got mine from Aquastone in the S.F. bay area. Box says "Suehiro sharpening stone" guess that explains it. Made in Japan though...
> 
> Dan*


Yup I think I know which stones you're talking about. I think those stones are used to sharpen chisels and plane blades.

I got my first batch of fingerstones from Mori when I was just starting. After that I started getting all my stones from Japan. Mori carries a lot of stuff and if you could catch him at a show, you could hand pick stones from his table. 

Here's a list of stones (and other polishing tools) that I use and works great with most of the blades I've worked on.

My About Page

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## Patrick Hastings

> _Originally posted by JohnD_ 
> *
> 
> I use a combination of synthetic and natural stones from Japan. For synthetic, I use Asahi brand from kongo-do to kasei-do. I use Asahi Chu-nagura-do and Koma-nagura-do but I also use natural nagura-do depending on the blade that I'm polishing. From Uchigumori to hazuya and jizuya its all natural. 
> 
> I'm not sure exactly what kind/brand of warerstones you're using but if they are the kind that you could pick up at a place like Japan woodworker (for example) then they are different. These kinds or water stones are more for sharpening rather than polishing. While Japanese Polishing stones sharpen the edge as well, it does work differently than water stones. I hope that makes sense 
> 
> Let me know how it works for you ok Dan
> 
> Cheers,*



John I think The word you might be looking for is friable. sharpening stones are generally a sintered cystaline mass. They dont  break down easily. On a microspopic level the tiney fractures of the crytals are iregular from one area to the next. This makes the stone jagged. So some areas bite deaper into the metal and leave you with scratches. The cutting action primarily comes from the stone directly, and a slurry dosnt help since as the stone breaks down it realeases a small quanity of durable  sharp irregular chunks that get pushed in deep into your blade and generally rip up the surface. 

 The stones that you want actually have Small individual particals of abrasive suspended in a friable matrix. The natural ones are sedimentary stones and they are held together by cementation rather than Sintering.  this allows them to break down faster and "release"  uniform sized particles rather than breaking off irregular chunks of extra hard grit. These regular particals form the slurry with the broken down matrix and roll around under the blade like ball bearings. The loose particals are what do the work.  They are uniform in size and spread out evenly distributing the the cutting action across the slurry between the stone and the blade. The better stones have more uniform particals in size and shape. The friable matrix lets the particals loose evenly arcoss the stone without jagged hard fractures. The synthetic polishing stones are meant to appoximate this effect, but I cant get a line on if there just lightly sintered or a type of cemented composite. 
   Anyway just so you know(not you John), Im not a polisher persay, but I do study abrasive theory, Cermics, and mineral/rock formations  :Smilie:  I have slowly been working on my own synthetic stones. I have produced a few sucessful prototypes. I hope to devote some more time to them one day. time is so short lately.

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## JohnD

> _Originally posted by Patrick Hastings_ 
> *
> 
> 
> John I think The word you might be looking for is friable. sharpening stones are generally a sintered cystaline mass. They dont  break down easily. On a microspopic level the tiney fractures of the crytals are iregular from one area to the next. This makes the stone jagged. So some areas bite deaper into the metal and leave you with scratches. The cutting action primarily comes from the stone directly, and a slurry dosnt help since as the stone breaks down it realeases a small quanity of durable  sharp irregular chunks that get pushed in deep into your blade and generally rip up the surface. 
> 
>  The stones that you want actually have Small individual particals of abrasive suspended in a friable matrix. The natural ones are sedimentary stones and they are held together by cementation rather than Sintering.  this allows them to break down faster and "release"  uniform sized particles rather than breaking off irregular chunks of extra hard grit. These regular particals form the slurry with the broken down matrix and roll around under the blade like ball bearings. The loose particals are what do the work.  They are uniform in size and spread out evenly distributing the the cutting action across the slurry between the stone and the blade. The better stones have more uniform particals in size and shape. The friable matrix lets the particals loose evenly arcoss the stone without jagged hard fractures. The synthetic polishing stones are meant to appoximate this effect, but I cant get a line on if there just lightly sintered or a type of cemented composite. 
>    Anyway just so you know(not you John), Im not a polisher persay, but I do study abrasive theory, Cermics, and mineral/rock formations  I have slowly been working on my own synthetic stones. I have produced a few sucessful prototypes. I hope to devote some more time to them one day. time is so short lately.*


Just like you said man!!! I wish I could have explained it like you did :Smilie:  I'm a sorry excuse for a polisher, can't even explain what it is I do :Frown:  I just scrub steel the best way I know how :Smilie: 

I totally agree with you Patrick. The slury is what does the work. The water acts like a shock absorber between the steel and the stone. 

Keep working on that synthetic stone man. You might come up with a stone that could manipulate the effects of the Uchigumori stone. That would be really cool!

Thanks for the explanation Patrick :Smilie:

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## Keith Larman

Actually what I was told by the makers of the asahi and tokkyu-hin synthetics was that the ideal use of most synthetic stones is without letting slurry build up, especially the coarser stones like the kongo-do and binsui-do from both asahi and tokyu-hin. They are built to break down quickly and are made from very fine, uniform particles, but using a slurry on them generally doesn't make much difference except for deepening some scratches making them harder to get out on the next stone and loading up the surface negatively affecting the stone's ability to cut. And the reason for the kongo-do and binsui in particular is material removal and shaping, so keeping the stone wet but clear of slurry will greatly reduce loading up and keep the stone cutting cleanly. It also happens a bit on synthetic kaisei in particular as the stones are finer but a "chunk" in the slurry can really make a deep scratch. If you don't keep the stone well washed and the surface dressed you'll likely be covering the blade with deeper scratches than you need to. That's why if you go over a blade initially on nagura you'll sometimes see some scratches that seem significantly harder to get out.

That's one reason the synthetic nagura stones are ultimately of limited value. They're fine, clean, but they don't develop a slurry that has the effect of a well matched to the blade natural nagura (which is very friable). So they tend to just burnish the blade without bringing out the activities and the really cool stuff that be hard to see. That burnishing effect can also burnish over scratches making them hard to see but then reappear in uchigumori as the stone opens them back up. "Hey, where'd that come from..."

The synthetic nagura are good in some respects as they are relatively inexpensive (compared to quality natural nagura) and they are uniform, but they don't have the effects that you traditionally want to start seeing at this stage of the polish. Heck, even within the natural nagura there's something like 9 different grades of nagura relating to hardness, friability, fineness, etc. And which one you pick will have a profound effect on how the hamon, hada and hataraki will appear later. The wrong stone can dig out too much material in the tani while leaving behind more hike. All really hard on a blade's lifespan. And an experienced person can look deeply into those areas and generally tell how talented the polisher was in picking stones. Its not obvious, but the guys who know their stuff can tell. Its an ongoing battle on each blade to keep those areas uniform and part of stone matching has a lot to do with the hamon type, activities, etc. in the blade as well as the steel's "feel". The stone that's perfect on suguha might be really not a good choice on an active choji. Or at least its use should be very different.

The right nagura will pull the scratches and open the steel. I have used my synthetic nagura as an initial run to clear some more persistant kaisei scratches and to keep the surface uniform, but then always now go to my natural chu and koma stones to pull up what the synthetics tend to burnish over. And I've found that the use of a top notch quality natural nagura can make or break the polish as much as the uchigumori. I've got a blade I'm working on now with profuse nie that the asahi nagura tended to suppress like I was running it over high grit sandpaper. Smeared. On some of the natural chu and koma I have the nie just "popped" out, bright and sparkly. Marvelous.

And again the uchigumori itself needs to be "matched" to the essence of the blade. Some introduce hike into the ji like there's no tomorrow and no amount of metoshi on the jido will pull those out. Hmm, which reminds me of why there are sometimes two steps in the work with the jido and jizuya. Different strokes, speed and different uses of tojiru vs. just clear water. Each method depends on what you're doing and relates to what Patrick is talking about. Slurry has one effect, clear water another.

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## JohnD

Good explanation as well and I totally agree with you're "different strokes for different folks" theory.  

I haven't had any problems (knock on wood) of "chasing scratches left by the previous stone" or burnishing hataraki at higher level. I also haven't had any problems of cutting clean or getting deep scratches by building up slury on my stone. It all depends on the blade I'm working on; I do get various results and looks at each stage. I have a series of 3-6 brands/types of each stone to choose from which gives me a good selection for the sword I'm working on. Like you said, "even the highest quality of stone could make or brake a polish". 

I guess I could say that technique has a big part on it as well. I was taught by a couple of well-respected polishers on how to avoid those problems. How to attack the blade angle, speed, stroke, amount of water/slury etc. and its been working great for me :Smilie:  

Anyway, Thanks again for the follow up explanation Keith. You always give good explanations of how things work :Smilie: 

Cheers,

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## Keith Larman

But regardless...




> _Originally posted by JohnD_ 
> *I guess I could say that technique has a big part on it as well. I was taught by a couple of well-respected polishers on how to avoid those problems. How to attack the blade angle, speed, stroke, amount of water/slury etc. and its been working great for me*


You must be learning a hell of a lot faster than me then because I still haven't figured that out. Glad its working for you because as always its a hell of a tricky thing for me.

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## JohnD

> _Originally posted by Keith Larman_ 
> *You must be learning a hell of a lot faster than me then because I still haven't figured that out. Glad its working for you because as always its a hell of a tricky thing for me.*


I must be seing double already from all this moving, sorry about that Keith :Smilie: 

However, I can't say that I'm learning faster than you though, I just have a lot of time to polish. That's all I do when I get off work and on weekends, just polish. Practice, experiment, pratice, read, practice, learn, then practice some more :Smilie:   But, there's always something new everyday and every blade. Its a never ending learning thing. I find it all to be good clean fun though :Smilie:  

Thanks again Keith :Smilie:

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## A. Ko

> _Originally posted by Dan Pfanenstiel_ 
> *How come my artificial 6000 grit stone just kind of smears with an oily kind of black film? Blade is clean. Tried nagura and without and same thing.
> 
> Dan*




I know this may sound brain dead, but there are water stones and there are stones that are require oil.  I've only used water sharpening stones - those are really bad for polishing it turns out as they tend to gouge steel.  It pays to get some good polishing stones.

Also, check to see if it's a waterstone or not.  If it's not, treating it as such could be a problem.

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