Question about What makes a Naniwa Crumble

[Lyon Heart]

I've been honing straight razors for a little over 5 years. I have a progression of Naniwa stones (600, 1000, 5000, 8000 & 12000). Overall, I am very happy with them. A couple years ago, I added the 5000 Naniwa when I had to replace an internet-purchased stone. When I realized that I was generating a lot of slurry and wearing the stone a lot more than creating an edge. I went down to a local knife store and was informed that some stones are much harder than others and ended up buying the 5000.

Two years after purchase it has developed an alligator pattern of fishers and last month a few chunks started falling off of it. I am wondering if I have treated it incorrectly. I was informed that the stone doesn't need to be soaked before use. I spray it with water a few times prior to use. I keep a slurry stone sitting in an inch of water beside it and between the slurry stone and spray bottle I hone with a very slurry. After use, I rinse it off in the kitchen sink and stand it on edge on a paper towel to dry overnight. After every four or five uses I run water over it and a flattening plate to keep it flat.

If you have any idea what I am doing that may be causing the crumbling I would appreciate your input.

 

[Huntdad]

I have used those stones and others for over 20 years and I have never had one do that. I follow the same process you are using for drying etc. Maybe you got a bad one? I highly recommend a coticule if you don't have one.

 

[Gamma]

Naniwa Chosera & Professional stones have been fraught with crazing and cracking issues for many years. It is not a new story at all. I recall the Chosera 5k being the main offender initially, guys were gluing them to boards so they didn't split apart.
Not every single Chosera/Pro does this though. So it's sorta like a hit-or-miss situation.
Back in 2010-2012 people were reporting cracking in their Chosera stones, it's been an ongoing issue for a long time.

 

[H Brad Boonshaft]

I suspect the stone got too wet or was in soapy water. My Snow White looks worse than yours. You can super glue the cracks and lap well, lap over a tray and save the slurry once dry, to fill deep cracks.

My old Snow White with all its cracks and filled divots still produces a near mirror bevel and super straight edge. It’s been cracked like that for years.

Try setting on edge on a couple chopsticks to allow air to get under the stone, the wet paper towel is like sitting in water. I dry on a wooden plate rack.

 

[Gamma]

Chosera stones have arrived new, unused, in original packaging, crazed and cracked. My first 10k arrived cracked. I know others who had to send new Chosera stones back because of crazing/cracking.

Naniwa has had an issue with the Pro/Cho stones for over a decade.
Compounding the obvious manufacturing issues, a lot of people don't follow the directions. They're not supposed to be soaked. Forced drying is another problem. Seems that most people don't read the instructions, choosing to take advice from other that have not read the instructions either.

FWIW, my 400C, 600C and 800C all spent several hours at at time in use, saturated to the gills. Not soaked, just wet from being wetted continually for a long while. No issues. My 1k and 3k, multiples of each, less time wet - mostly all fissured.

But - many users that never soaked their Chosera/Pro stones have seen them craze, crack. Sometimes the crazing stays stable, other times not. Sometimes it can be lapped out, other times it comes back.
I've seen mounted 5k Choseras that were never soaked split in half. So you never know what to expect really.

I would assume that any stone with a network of hairline cracks is working on borrowed time. If pieces of the stone are crumbling, then I would dispose of it.

Seems to be a Naniwa thing, there have been several reports recently of their Hayabusa 4k stones cracking. And they have a different binder.

 

[Loner16]

All this is news to me...

I have the Chosera/Professional series in 1,3 and 5K. The 5K is used quite often, the others less so as we go down in grit. I have no cracking/crazing whatsoever of any kind. None, nada, zilch nil, nyet... NOTHING. The original Snow White is another issue, but my crazing is slight and nearly imperceptible. But, I'm very careful with these synthetics, as the OP seems to have been. He can't be faulted for his care of the stones..
I do submerge mine in water for perhaps a minute before use, because they are thirsty, but I dry them naturally for days before putting them away. Do I have the secret formula?? I don't think so!

In any case, I'm glad this issue has not reared it's ugly heard for me... I happen to like the Chosera/Professional series stones...

 

[JPO]

All this is news to me...

I have the Chosera/Professional series in 1,3 and 5K. The 5K is used quite often, the others less so as we go down in grit. I have no cracking/crazing whatsoever of any kind. None, nada, zilch nil, nyet... NOTHING. The original Snow White is another issue, but my crazing is slight and nearly imperceptible. But, I'm very careful with these synthetics, as the OP seems to have been. He can't be faulted for his care of the stones..
I do submerge mine in water for perhaps a minute before use, because they are thirsty, but I dry them naturally for days before putting them away. Do I have the secret formula?? I don't think so!

In any case, I'm glad this issue has not reared it's ugly heard for me... I happen to like the Chosera/Professional series stones...

I guess I have been lucky with my Chosera/Professional. Even the snow white don't show any sign of cracking or crazing.
I am not sure if it makes a difference. I don't submerge them in water, and they don't stay wet that long.
They are also drying in a cool environment slowly.

 

[life2short1971]

I've been honing straight razors for a little over 5 years. I have a progression of Naniwa stones (600, 1000, 5000, 8000 & 12000). Overall, I am very happy with them. A couple years ago, I added the 5000 Naniwa when I had to replace an internet-purchased stone. When I realized that I was generating a lot of slurry and wearing the stone a lot more than creating an edge. I went down to a local knife store and was informed that some stones are much harder than others and ended up buying the 5000.

Two years after purchase it has developed an alligator pattern of fishers and last month a few chunks started falling off of it. I am wondering if I have treated it incorrectly. I was informed that the stone doesn't need to be soaked before use. I spray it with water a few times prior to use. I keep a slurry stone sitting in an inch of water beside it and between the slurry stone and spray bottle I hone with a very slurry. After use, I rinse it off in the kitchen sink and stand it on edge on a paper towel to dry overnight. After every four or five uses I run water over it and a flattening plate to keep it flat.

If you have any idea what I am doing that may be causing the crumbling I would appreciate your input.

The Snow White 10k does that with me. I have been through 4-5 over the years and I don’t know why they crack. I’ve had other Naniwa without any issue whatsoever. I have a 12k I use frequently with none of the checking the 10k gets.
Good luck but you may never find your answer.

 

[life2short1971]

The Snow White 10k does that with me. I have been through 4-5 over the years and I don’t know why they crack. I’ve had other Naniwa without any issue whatsoever. I have a 12k I use frequently with none of the checking the 10k gets.
Good luck but you may never find your answer.

Its too late for me to correct my mistake but it was the 8k. My apologies.

 

[cotedupy]

Naniwa Crumble

Take 5 or 6 large cooking apples and cut into rough chunks. Simmer for about 5 mins with a little water, lemon juice, sugar and cinnamon. Place in a baking tray.

Crush your Naniwa stones into a fine powder and mix in your hands with salted butter and demerara sugar. You're aiming for a breadcrumb-like consistency here.

Cover the apples with with the crumble mixture and bake at a medium heat for about 45 mins.

---

You can tweak this recipe as you fancy; rhubarb makes a nice addition, or blackberries in the autumn. And indeed any other brand of useless whetstone will work just as well.

 

[Frito Ray]

My first thought was that the soaked stone was not fully dry before being exposed to freezing temperatures. But based on the number of folks it happened to, it points more to a manufacturing defect.

 

[Steve56]

Naniwa Crumble

Take 5 or 6 large cooking apples and cut into rough chunks. Simmer for about 5 mins with a little water, lemon juice, sugar and cinnamon. Place in a baking tray.

Crush your Naniwa stones into a fine powder and mix in your hands with salted butter and demerara sugar. You're aiming for a breadcrumb-like consistency here.

Cover the apples with with the crumble mixture and bake at a medium heat for about 45 mins.

---

You can tweak this recipe as you fancy; rhubarb makes a nice addition, or blackberries in the autumn. And indeed any other brand of useless whetstone will work just as well.

And clean your teeth too !

 

[JPO]

Naniwa Crumble

Take 5 or 6 large cooking apples and cut into rough chunks. Simmer for about 5 mins with a little water, lemon juice, sugar and cinnamon. Place in a baking tray.

Crush your Naniwa stones into a fine powder and mix in your hands with salted butter and demerara sugar. You're aiming for a breadcrumb-like consistency here.

Cover the apples with with the crumble mixture and bake at a medium heat for about 45 mins.

---

You can tweak this recipe as you fancy; rhubarb makes a nice addition, or blackberries in the autumn. And indeed any other brand of useless whetstone will work just as well.

That is the recipe Morihei uses. They also add some jnat crushed rock and some grey die.
This is where all the Ozuku small bits go.
And don't forget the angel dust and unicorn oil.
Shaken, not stirred.

 

[Loner16]

Speaking of recipes, when I was a younger man, we used to gout on big water in layout boats to shoot coot.. better known as sea ducks. It was quite challenging hunting, but the ducks themselves were not very palatable. We used to give ours to a gent that had a Filipino wife, who could make them edible.

In any case, there is a great recipe for coot...

Boil them in a large pot of water... After a while, throw in a brick. When fully cooked, throw away the coot and eat the brick!

 

[cotedupy]

Speaking of recipes, when I was a younger man, we used to gout on big water in layout boats to shoot coot.. better known as sea ducks. It was quite challenging hunting, but the ducks themselves were not very palatable. We used to give ours to a gent that had a Filipino wife, who could make them edible.

In any case, there is a great recipe for coot...

Boil them in a large pot of water... After a while, throw in a brick. When fully cooked, throw away the coot and eat the brick!

Excellent! Which in turn reminds me of an old '50s cookbook I found at my gran's one time, which as far as I could work out was half serious, half p*ss-take. There was a recipe for grilled eel which began:

First kill and skin your eel. As with the earlier recipe for cooking cats there are likewise many ways to skin an eel, but the following is recommended...


[You will be relieved to hear that there wasn't actually a recipe for cooking cats. There was bear meat though.]

 

[Gamma]

The Snow White 8k does that with me. I have been through 4-5 over the years and I don’t know why they crack. I’ve had other Naniwa without any issue whatsoever. I have a 12k I use frequently with none of the checking the 8k gets.
Good luck but you may never find your answer.

FTFY

The Chosera/Pro/Finishing Stone (Snow White) are all magnesia binder stones, the Super Stones are what people call resinoid. Historically, magnesia binder stones have been prone to issues. Shapton Pro had the same problem early on but it was resolved somehow, it seems. Other brands had similar situations. There are too many theories about why to post here, but the magnesia binder seems to be a core element in the story though.
Odd thing - on the sides of Chosera and Jyunpaku, there is a recommendation to not soak for more than an hour. But Naniwa's instruction sheet (how to sharpen PDF) says differently; the Professional, Super, and Finishing Stone have a 'no soak, just spritz' recommendation.

Chosera stones seem to be in production still but only for the Japanese market and only on bases.

The Superstones, being resin, seem to not be prone to cracking, but some of them will warp.

 

[cotedupy]

Shapton Pro had the same problem early on but it was resolved somehow, it seems.

Oh are the SPs the same kind of Magnesia bind as NP? Didn’t know that. Certainly I’ve left Shaptons in water pretty much all day, taken them out, then done the same thing again a few days later without any issues at all.

Sounds like there must be something else going on with the Naniwas too then...

 

[JPO]

Does the type of water factor in?
In my area the water is generally rich in minerals, an we do not use water softeners.

 

[Gamma]

Naniwas, and other magnesia binder hones, have been cracking all over the globe, so I'd guess the type of water is not a factor.

Magnesia Binder - infers that there is Magnesium Oxide in the binder. As to the rest of what is in there, dunno. But - I think, based on feel, that Shapton's binder is at least 'similar' to Naniwa's for the Pro/Cho line. But maybe enhanced. Maybe because they're 15mm thick and not 20mm or 25 mm thick, maybe thinner stones dry better... dunno.

The binder info comes from sources 'in the business' but not Shapton directly; they once said the binder is 'clay'... which is not very descriptive. I am inclined to think it contains Magnesium Oxide though.

I know a few guys that permasoak Shapton Pro stones without issue. I wouldn't do that, but I've seen their kits first hand and their stones are fine. One of them keeps a 30k Pro sitting in a box with water 24/7/365...no issues. Doesn't mean it will work for everyone I guess.

 

[cotedupy]

Does the type of water factor in?
In my area the water is generally rich in minerals, an we do not use water softeners.

Doubt it.

Naniwa are just playing everybody for fools I think. Much like the way 50% of Apple products inexplicably stop working within 24hrs of the warranty period being up, but the other half go on for years.

There are just enough known unknowns for people to persevere...