Naniwa Chosera 3000 cracking?

Discussion in 'Sharpening Station' started by tbott, Jan 6, 2014.

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  1. Jan 6, 2014 #1

    tbott

    tbott

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    Soooooooo what gives? Seem to be getting hairline cracks in the stone. There also seems to be some kind of dark spot/stain in the other side. I treat it exactly the same as my Chosera 1000, and nothing has happened to that stone. Am I doing something wrong? I soak the stone for about 30 minutes, flatten probably every other time I use it with a DMT XX course, and when I'm done I let the stones dry completely. Any suggestions would be nice, not trying to destroy an expensive stone. Thanks!

    T
     
  2. Jan 6, 2014 #2

    tagheuer

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  3. Jan 6, 2014 #3

    bahamaroot

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    Seems to be becoming a more common problem with Chocera.
     
  4. Jan 6, 2014 #4

    Dave Martell

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    I'm positive that these problems (cracking Choseras) are due in great part to them being baseless. You see the based version was all that was sold until an fake surgeon (AKA - an idiot) came along and convinced the first US retailer to order a batch of baseless Choseras. This then set the precedence of baseless Naniwas being sold in the US as demand (and competition) was high. Now the customers are paying the price of the stupidity of others.

    These stones flex and warp and even disintegrate if soaked long enough. They are so much more stable if mounted to a base. Only order Choseras that are mounted on a base OR mount them immediately!
     
  5. Jan 6, 2014 #5
    Dave, is that also true of the Superstones?
     
  6. Jan 6, 2014 #6

    Dreezzzzz

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    The Chosera's are splash and go stones. They should not be soaked. I know some people think it works better when soaked. According to the vender I bought them knives & tools. Dutch branch of Eden webshop Naniwa states these stones should not be soaked. This could explain the cracking. The 3000 seems to be softer than the 1000. This could explain the 3000 crash cracking earlier.
    Off coarse I haven't sold them like Dave, so mounting sounds like a "stable" thing to do! All my chosera's are with a base


    Sent from my SM-N9005 using Tapatalk
     
  7. Jan 7, 2014 #7

    Benuser

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    The base won't prevent them from cracking, but will make the consequences less dramatic.
     
  8. Jan 7, 2014 #8

    Ruso

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    I've seen a lot of posts about choseras cracking. So seems like a common thing. The only one that seems to be less likely to crack is Chosera 800. I would follow Dave advice and mount it. For myself I made a decision that if I buy another chosera (unlikely atm) it will be a mounted one.

    While Dave will have better info. Superstones seems to be pretty crack resistant. Do not soak them for more then 5 minutes though.
     
  9. Jan 7, 2014 #9

    Dreezzzzz

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    I read this on Fine-Tools:

    IMPORTANT NOTE on storage and lubrication: Chosera sharpening stones are bound with magnesium and so have more cutting particles per unit of surface than resin-bound stones. But magnesium-bound stones are much more sensitive to prolonged exposure to water as other types of stones. So Chosera stones should NOT be left to soak in water for prolonged periods and must be stored dry. If this advice is not followed the stones can develop hairline cracks or the binding material can be leached out of the stone. It is more than enough to pour a little water on the surface or briefly dip the stones in water, they do not need to be soaked. If you are not sure that you can keep this always in mind, perhaps because you have a number of different kinds of sharpening stones, it may be better to opt for the more tolerant Super Stones.

    From a other forum I read that it could also be caused by not drying evenly. To prevent the outside drying much faster than the inside you can dry the stone with a microfiber cloth after sharpening. Then wrap the stone with this damp cloth to prevent the outside drying much faster.

    You should flatten your stone to get rid of the hairlines and stop them getting any bigger
     
  10. Jan 7, 2014 #10

    Dave Martell

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    I can't recall ever hearing about a Superstone cracking although maybe I have and just forgot, sure doesn't ring a bell as being a problem like the Choseras are.
     
  11. Jan 7, 2014 #11

    tbott

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    Thanks all! I'm glad this seems to be a recurring problem and not just user stupidity (though there's still some of that). I'll work on getting it mounted. Can one buy empty bases and just glue them one, or is the same time and effort to just make one? Also I'll stop soaking them. Is the DMT xx coarse too rough to flatten a 3000 grit stone? Should I look for something finer? I'm about to make a higher grit stone purchase, and I think I'll opt for the 5000 super stone instead of Chosera. Thanks for all the help!

    T
     
  12. Feb 4, 2014 #12

    berko

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  13. Feb 4, 2014 #13

    Dave Martell

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  14. Feb 22, 2014 #14

    bahamaroot

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    tbott - " I soak the stone for about 30 minutes."

    Choceras are suppose to be slash-n-go, I think people are soaking them to long. To many long soaking and long drying sessions.
     
  15. Jan 17, 2019 #15

    Drayquan

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    I had this for a few weeks then this happened. I never soaked it, and I let it dry properly after using.

    [​IMG]
    [​IMG]
    [​IMG]
     
  16. Jan 17, 2019 #16

    Knife2meatu

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    That's sucks.

    Out of curiousity, what's the date printed on the stone? How long were your sharpening sessions? How, exactly, did you let it dry?

    In the second picture, at the bottom of the stone, where there's a gap between the base and the stone, it looks a little shiny and there's what looks like a dark line made by water/slurry coming off the stone -- would you say that liquid pooled there and soaked into the stone for prolonged periods?
     
  17. Jan 17, 2019 #17

    Grunt173

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    I have a Chosera 400,800 and 3k pros and they have all cracked. Have only just briefly splashed and go,no soaking whatsoever.I have three more,a 400,800 and a 3k but they have the base and have never been out of the box yet.Don't know if they will be either.Might even end up selling them if I get the notion.
     
  18. Jan 18, 2019 #18

    Drayquan

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    I treated this as a finishing stone for everyday stainless, so it really didn’t get that much use before these cracks appeared. Just light burr removal, light edge refinement / stropping on this one.

    I did use it on some higher end carbon blades 62-64hrc as a progression towards 8k, but even then it was used gently, with a little squeeze bottle of water to splash n’ go.

    After using it, I’d dab it with a dry towel (not rub, just lightly dab), then store it on a shelf at room temperature.

    I suppose it’s possible that moisture may have pooled slightly in that bottom area of the chosera plastic base around the edges.
     
    Last edited: Jan 18, 2019
  19. Jan 18, 2019 #19

    Nemo

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    Out of interest, was the stone sealed?
     
  20. Jan 18, 2019 #20

    Drayquan

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    Do sharpeners “seal” stones? Is that a thing? What kind of sealant?
     
  21. Jan 18, 2019 #21

    kdeleon

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    I haven't done it with artificial stones but with naturals, I know many use shellac to prevent cracking.
     
  22. Jan 18, 2019 #22

    Drayquan

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    Shellac around the base/sides of the stone? I can’t imagine anyone using shellac on a chosera’s surface....?
     
  23. Jan 18, 2019 #23

    kdeleon

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    Correct, side and base. Well this one has the plastic base so that side is covered. And yes, not the surface.
     
  24. Jan 18, 2019 #24

    Knife2meatu

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    I think a lot of the problem is the adhesive under the stones doesn't actually cover the entire surface. Every Chosera/Superstone which I've removed from their base has had, at most, maybe 50% of the interface covered in adhesive: the adhesive is applied along the long axis of the stone, toward the center; and has some significant thickness, perhaps 1/32". So there's a void along the edges of the undersides of the stones, where water will enter, remain, and absorb into the stone unless some little effort is made to remove it. This is compounded by the small lip molded around the top of the base, which catches water.

    Furthermore, from what I've seen, Naniwa's production process always places the stones off-center prior to gluing; which means that although one side is right against the lip, the other side has a wider opening. This wider-open side happens to be the one above pictured.

    Now consider how the stone dries if water pools under it -- it will have time to thoroughly soak in, and dry very slowly -- while the top, most exposed to air, has water drawn down and away from it by gravity: the top will be totally dry as the bottom will still be quite saturated. Or so it seems to me, anyway.

    For what it's worth, I've been using Choseras with bases (400 to 5000 + baseless 8k Snow White) for around 18 months now, systematically drying them upside down, and have seen virtually not a single sign of even minor crazing -- the single exception being a tiny spider web once on my 3K.
     
  25. Jan 18, 2019 #25

    Nemo

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    I sealed mine with marine grade lacquer. It would have sealed the interface between the base and the sides. I have had zero cracking (but I don't know whether the sealing is responsible for this or not).
     
  26. Jan 18, 2019 #26

    kdeleon

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    I have two of their stones and haven't tried to seal it. Actually didn't even know cracking was a problem for these stones until I started seeing these threads. But how did you remove the base? I would think, for me, that would introduce more risk of cracking than just chancing it as is.

    Finally, I do dry my stones out on their sides. So I wonder if that helps some of the pooling issues you mention. Maybe at least partially.
     
  27. Jan 18, 2019 #27

    Grunt173

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    I also stack and dry my baseless pro choseras on their sides in a drying rack,still cracked. I have since started drying my Choseras with a damp towel around them so the drying is slowed down and evenly dried, hoping that it helps.
     
  28. Mar 24, 2019 #28

    kwk1

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    Lacquer sounds like a good idea.
    I wonder if silicone would work around the base.
     
  29. Mar 24, 2019 #29

    Knife2meatu

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    Seeing this thread pop back up reminds me of something I saw a couple months back, related to Japanese Youtube sharpening enthusiast virtuovice, whose cracking Choseras it was which were mentioned higher up in this thread:
    I was watching one of his recent Japanese videos (www.youtube.com/watch?v=v-GEZmNIMf4&feature=youtu.be&t=423) and noticed that his green Shapton 2k has some pretty significant cracking running across its surface:
    [​IMG]
    It doesn't seem to hurt his use of the stone too much however. He follows up the 2k Shapton with a 3k Chosera which also shows significant cracking, but occurring in more of a spider web pattern which I recognize from my own Choseras.
     
  30. Mar 24, 2019 #30

    Nemo

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    The lacquer seems to do a good enough job.
     

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