What can I expect from a hairline crack in a stone?

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Rufus Leaking
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What can I expect from a hairline crack in a stone?

Post by Rufus Leaking » Thu Jul 13, 2017 9:29 pm

I have an oishi combo stone- nice stone, 3k/8k, and I just discovered a hairline crack that runs from one side of the stone to the other, really small, looks just like a hair is laying on the stone. It only runs halfway through the stone. This is a splash & go, and while I've never left it to soak intentionally for any real time, it has been wet for periods of a half-hour to an hour. I usually just spray it with a mister, but the last two times I've used it, I let it soak with my other stones. I find it hard to believe that such a short period of time in water could damage a water stone. After all, it is called a water stone.

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Kit Craft
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Re: What can I expect from a hairline crack in a stone?

Post by Kit Craft » Thu Jul 13, 2017 9:53 pm

Rufus Leaking wrote:
Thu Jul 13, 2017 9:29 pm
I have an oishi combo stone- nice stone, 3k/8k, and I just discovered a hairline crack that runs from one side of the stone to the other, really small, looks just like a hair is laying on the stone. It only runs halfway through the stone. This is a splash & go, and while I've never left it to soak intentionally for any real time, it has been wet for periods of a half-hour to an hour. I usually just spray it with a mister, but the last two times I've used it, I let it soak with my other stones. I find it hard to believe that such a short period of time in water could damage a water stone. After all, it is called a water stone.
I had this happen with a Naniwa 1k/3k combo and it split on me a few weeks later. Normally if I get a crack then I lacquer the sides and bottom of the stone. Not so much a possibility with a combo stone. I guess you could do so with just the sides but I do not know how much help it would be.

On the other hand, I have a shapton glass 2k with mega cracks, three of them, that has not shown any issues in over 2 years. Now, these cracks were caused by me dropping the stone on the floor. However, this stone is mounted on glass so even if it has split in half it is held together by the glass plate. Not so much an option for a combo stone. :(

Rufus Leaking
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Re: What can I expect from a hairline crack in a stone?

Post by Rufus Leaking » Thu Jul 13, 2017 10:08 pm

Yeah, Kit- I'm pretty pissed. I never dropped this stone, never mistreated it, used it mebbe a half-dozen times, and it ran $100. If it continues, and breaks, there's not much I can do. I could epoxy it, I guess, but I'm tryna figure out WTF caused this. Was your Naniwa a soaker? I think they all are, aren't they? The only thing I can think is the stone can't take being wet, which would have been nice to know. Swear to god the thing wasn't underwater an hour- EVER- and it has always had a bunch of time to dry between uses. Another thing that gets me is - how did BOTH sides wind up with a crack? There must be some adhesive between the two sides- seems as if that would stop any crack(s) from spreading....

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Kit Craft
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Re: What can I expect from a hairline crack in a stone?

Post by Kit Craft » Thu Jul 13, 2017 10:20 pm

It has been quite awhile but yes, I think it was a soaker.

nevrknow
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Re: What can I expect from a hairline crack in a stone?

Post by nevrknow » Fri Jul 14, 2017 8:37 am

Do you have a way to lap/flatten the stone? In my limited experience if I have one with a crack I lap it flat and then always sharpen at an angle over the crack. The thinking being 2 edges but at the same height. Never straight into the crack with the blade. But I always sharpen at an angle on stones.

No issues with that way. Like I said just the way I do it if it helps any.

Rufus Leaking
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Re: What can I expect from a hairline crack in a stone?

Post by Rufus Leaking » Fri Jul 14, 2017 9:02 am

Yeah- I have the DMT plate. What's strange is - when the stone is dry, the crack pretty much disappears- evidently, the stone swells considerably when wet. I think I'm going to retire it, I got it from Lie Nielsen for sharpening plane blades. It really doesn't fit my progression for knives. I'm going to replace it with the Rika 5k. I'll never buy another combination stone.

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Jeff B
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Re: What can I expect from a hairline crack in a stone?

Post by Jeff B » Fri Jul 14, 2017 3:31 pm

Rufus Leaking wrote:
Thu Jul 13, 2017 10:08 pm
...Was your Naniwa a soaker? ...
Naniwa does not make soaking stones, they are all splash-n-go because most have a magnesium binder that degrades in water. They don't recommend soaking any of their stones. Several people soak the Naniwa Aotoshi 2K Green Brick before using and get away with but it's size probably aids in that. There have been many complaints over the past few years about Naniwas cracking and soaking or prolonged exposure to water/moisture over time is usually a factor.
If God wanted me to be a vegetarian he wouldn't have made animals taste so good.

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Kit Craft
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Re: What can I expect from a hairline crack in a stone?

Post by Kit Craft » Fri Jul 14, 2017 5:15 pm

Jeff B wrote:
Fri Jul 14, 2017 3:31 pm
Rufus Leaking wrote:
Thu Jul 13, 2017 10:08 pm
...Was your Naniwa a soaker? ...
Naniwa does not make soaking stones, they are all splash-n-go because most have a magnesium binder that degrades in water. They don't recommend soaking any of their stones. Several people soak the Naniwa Aotoshi 2K Green Brick before using and get away with but it's size probably aids in that. There have been many complaints over the past few years about Naniwas cracking and soaking or prolonged exposure to water/moisture over time is usually a factor.
The traditional stones are listed as needing a soak not only on this site but on many others. The same with the Economical stones. I don't know what Naniwa says about this, just saying what I have read on the vendor sties.

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Jeff B
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Re: What can I expect from a hairline crack in a stone?

Post by Jeff B » Fri Jul 14, 2017 9:08 pm

You are correct Kit and I'm thinking this might have been one of the changes with some of their stones back when they "improved" them and changed the original names. It's been awhile since I've been on the Naniwa site, looks like I need to go back and research changes to the stone line ups.
If God wanted me to be a vegetarian he wouldn't have made animals taste so good.

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Kit Craft
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Re: What can I expect from a hairline crack in a stone?

Post by Kit Craft » Fri Jul 14, 2017 9:49 pm

Jeff B wrote:
Fri Jul 14, 2017 9:08 pm
You are correct Kit and I'm thinking this might have been one of the changes with some of their stones back when they "improved" them and changed the original names. It's been awhile since I've been on the Naniwa site, looks like I need to go back and research changes to the stone line ups.
I'm not sure I would bother...the traditional stones are not what I would call improved. :lol: The economy lineup even less so. The only reason I got the 1/3k combo is because it came with a 220 (I think) a fixer and a universal stone holder. This was an early set before I even found this place or J-knives. I used it on my Mora and other "bushcraft" knives. The whole package was something like $50. I got what I paid for. :lol:

Chefcallari
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Re: What can I expect from a hairline crack in a stone?

Post by Chefcallari » Sun Jul 16, 2017 3:28 pm

Jeff B wrote:
Fri Jul 14, 2017 3:31 pm
Rufus Leaking wrote:
Thu Jul 13, 2017 10:08 pm
...Was your Naniwa a soaker? ...
Naniwa does not make soaking stones, they are all splash-n-go because most have a magnesium binder that degrades in water. They don't recommend soaking any of their stones. Several people soak the Naniwa Aotoshi 2K Green Brick before using and get away with but it's size probably aids in that. There have been many complaints over the past few years about Naniwas cracking and soaking or prolonged exposure to water/moisture over time is usually a factor.
Im pretty sure only the "Professional" aka choseras are magnesium bonded... Thats part of there claim to fame. The super stones have a different binder and the traditional are just that...traditional clay baked. I think the reason alot of combo stones crack is because its 2 different grits being bonded and soaked... So when they get soaked and dried the expand and contract at different rates. Lol never been a combo stone fan.

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ken123
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Re: What can I expect from a hairline crack in a stone?

Post by ken123 » Sun Jul 16, 2017 6:30 pm

If you want to make the effort, you could get the sides of the stone lacquered, which will give it some support. You don't have to lacquer all sides.

Not all combo stones will have this problem. For instance the 150/1200 Nubatama combo stone has an interface layer between the stones, blocking crack propagation. You also see this between the Shapton GlassStones and the glass plate, however even so if the glass shatters, it can take the stone with it, since tempered glass will not tolerate cracks without catastrophic results.

You could just put some nail polish around the stone, cross your fingers and call it a day :( If it was an expensive stone I would cut it in half between the stones and glue it to two separate backings, repairing the stones if they cracked further. But that's me :)

I'll pass on commenting further on the Naniwa stones here.

---
Ken


Rufus Leaking
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Re: What can I expect from a hairline crack in a stone?

Post by Rufus Leaking » Sun Jul 16, 2017 7:03 pm

Sadly, no on the pics. I'm not that sophisticated here on this format, but the crack has probably been there for a while. It is really hairline, like Yul Brenner hair- really fine. It goes from halfway on one side to a little less than halfway on the other side, and it includes the side, running through both grits . It is toward the last 1/4 of the stone if that helps. I will continue to use it for woodworking, but I'm buying the Rika 5k tomorrow, and that is a better finish for my progression of- the kohetsu 800(which I REALLY LIKE) to the Bester 1200, the GBOJ, then the Rika 5k. The 3k/8k is unnecessary.

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Kit Craft
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Re: What can I expect from a hairline crack in a stone?

Post by Kit Craft » Sun Jul 16, 2017 7:55 pm

Rufus Leaking wrote:
Sun Jul 16, 2017 7:03 pm
Sadly, no on the pics. I'm not that sophisticated here on this format, but the crack has probably been there for a while. It is really hairline, like Yul Brenner hair- really fine. It goes from halfway on one side to a little less than halfway on the other side, and it includes the side, running through both grits . It is toward the last 1/4 of the stone if that helps. I will continue to use it for woodworking, but I'm buying the Rika 5k tomorrow, and that is a better finish for my progression of- the kohetsu 800(which I REALLY LIKE) to the Bester 1200, the GBOJ, then the Rika 5k. The 3k/8k is unnecessary.
You will enjoy the rika, it is a great stone.


Rufus Leaking
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Re: What can I expect from a hairline crack in a stone?

Post by Rufus Leaking » Sun Jul 16, 2017 9:22 pm

Thanks, Ken- will do. @ Kit- I think the Rika will be a suitable end here.

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