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Recommendation? Condition Ceramic stone

Discussion in 'Maintenance, Tinkering & Embellishment' started by samuraistuart, Feb 19, 2019.

  1. samuraistuart

    samuraistuart KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Dec 21, 2006
    I did an advanced search on this subforum, in the thread titles, "Condition ceramic" and got nothing. I know it's been discussed before, but maybe not in a dedicated post.

    What is the best method to condition a ceramic stone, specifically sintered ceramics like the Spyderco stones? How do you know when it needs to be done?

    My guess is to use a cheapo diamond plate, but I wonder which grit is best. Coarse? Fine? Extra Fine? I'm a bit puzzled as to how the coarser grits of the diamond plate would change the fine, or ultra fine, Spyerdco stone surface "grit rating".

    Would SiC powder and a lapping plate be another option?

    As far as when you should recondition, I guess the simple answer is "when the stone stops cutting". But the F and UF stones don't really "cut", but rather give more of a polish. I guess the next answer would be "when they stop polishing". Maybe the correct answer is "when the stone is loaded". I really don't know. I have both the F and UF stones, I use mineral oil to keep swarf suspended, and if/when I do see the occasional black streak, it gets cleaned with Bar Keeper's Friend. So both stones are maintained to look like they're brand new, but wanted a more informed opinion as to the best time and method to condition them.

    Thanks ahead of time for your thoughts.
    115Italian likes this.
  2. Mr.Wizard


    Feb 28, 2015
    Loose silicon carbide grit worked for me. I would start coarse, like #60, and let it break down as you work, only using a finer grade if necessary. This leaves a smooth matte finish that seems to cut pretty well.
    samuraistuart likes this.
  3. FortyTwoBlades

    FortyTwoBlades Baryonyx walkeri Dealer / Materials Provider

    Mar 8, 2008
    Loose SiC grit will work best. A fine diamond plate will work well, too, but the grit of the plate will impact the performance of the ceramic. The fine and ultra-fine Spyderco stones are compositionally identical, with the UF having been machined smooth. Think of it acting more like a file with the scratches from the diamond plate making the "teeth".
  4. Haffner


    Feb 13, 2007
    The Spyderco stones are ready to use, so conditioning is not needed.
    Beware, that lapping the stones anyway will change the way they grind, which may not be desirable.

    Many people use Barkeepers Friend or a similar product to clean their Spyderco stones
  5. Chris "Anagarika"

    Chris "Anagarika"

    Mar 7, 2001

    You’re lucky. David did remind us about this recently.

    There was an old thread about making Spyderco F into UF (or the other way around?) but I cannot remember by whom .. :eek:

    This is good but not the one I remember

    Nor this one

    Found it
    Last edited: Feb 21, 2019
    Mr.Wizard likes this.
  6. David Martin

    David Martin Gold Member Gold Member

    Apr 7, 2008
    I leveled my Spyderco fine (it only needed it on one side) using a coarse then fine diamond plate. I was able to bring that side to a extra fine
    level. Some have done this instead of purchasing the ultra fine ceramic stone for 70$. This worked but a fine SiC stone may work as well. DM
    Chris "Anagarika" likes this.
  7. My experience mirrors David Martin's post above, in using DMT's Coarse (and/or Fine) hones to produce something emulating a UF finish on Spyderco's ceramics.

    I've mentioned it before, but I used either/both sides of DMT C/F DiaFold hone to do this with one of my Spyderco DoubleStuff hones. I started that project sort of blind at the time, intent mainly on flattening both sides of the DoubleStuff (which were somewhat upturned at the edges), but not knowing how it would affect the finish. I put everything in a pan of water, to do the work fully immersed. That helped to keep the diamond hone free of collected swarf, which also helped me minimize use of pressure on the diamond hone. The DiaFold was noticeably worn after the work was done, but still functional as a hone. Didn't kill the hone, either, which itself impressed me in it's durability, considering the limited surface area doing such a heavy job.

    Both sides of that DoubleStuff came away from lapping with a working finish noticeably finer than the factory's original 'Fine' side of the hone. They also cut very well in sharpening blades (evidenced by large amounts of very, very fine swarf generated), but to a much finer finish than I'd previously seen from either the Medium side or the Fine side of that hone.

    So, if one happens to be intent on making a 'UF' out of a Spyderco Medium or Fine, then that seems to be one way to get it done.
    Last edited: Feb 21, 2019
    Chris "Anagarika" likes this.
  8. FortyTwoBlades

    FortyTwoBlades Baryonyx walkeri Dealer / Materials Provider

    Mar 8, 2008
    It's worth noting that in most cases fully flattening these stones isn't necessary because the degree to which they're out of true is less than the natural variation your hands end up making, and also less than what commonly happens to most sharpening stones' surface after a single sharpening job, or even during it. Absolute dead flat is only needed in very exacting circumstances that are not at all common.
    Chris "Anagarika" likes this.
  9. The reason I was intent on flattening my DoubleStuff hone, is because it's upturned edges (dished or 'cupped', in essence) were rolling the edge on every knife I tried to sharpen with it. The crisp, upturned edge of the hone becomes a pressure-focus point, laterally against the blade's edge, if it makes even momentary contact during the sharpening pass. Much more an issue on dead-straight edge profiles (sheepsfoot or wharncliffe blades, for example), of which their profile demands flush & flat contact along a lengthy portion of the blade's edge. On such a blade, the only contact is at each upturned edge of the dished hone, with a visible gap underneath the blade in the central portion of the hone.

    If the hone were slightly crowned instead, i.e., higher in the central portion and low at the edges, I wouldn't have worried about it.

    These days, with every new stone I buy, I always look for those upturned edges first thing. If I see it, the stone immediately gets resurfaced, at least with the intent of knocking those high edges down. Either that, or I'll sometimes just radius the edges of the stone slightly, which also sets it up for work on blades with some recurve in them.
    Chris "Anagarika" and lex2006 like this.
  10. samuraistuart

    samuraistuart KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Dec 21, 2006
    New they are ready to use of course. I have a “fine” that has been used for years upon years and didn’t cut well any longer. I used a fine diamond plate and it seemed to help, temporarily. Bar keepers friend is also one of my favorite stone cleaning (and blade cleaning) products. Erasers work well too.

    Chris, thanks for the threads.

    The diamond plate I used was one of the cheaper brands (Smith’s?). Fine. I also kept running water while trying to condition the ceramic. I wasn’t necessarily trying to flatten so much as to just try to bring it back to a better cutter like I remembered.

    Then I bought the UF. I had heard both the fine and ultra fine were the same stone, but the UF was lapped to a finer surface finish or whatever. Honestly I can’t tell the difference between the two. Except the blue vs black boxes! It may be that the fine stone is just so old, and my attempt using a fine diamond plate, made it finer than it came when new. It’s been so long since it was new....

    When I get the time I will try loose 60 grit and then 120 grit SiC, as I have some that came with a sigma power ceramic 120 that I don’t use much any longer. Maybe that will give me better results than a fine diamond plate. The plate seemed to work fairly well, but I remember a more aggressive cut with that stone.
    Chris "Anagarika" likes this.
  11. drail


    Feb 23, 2008
    FortyTwoBlades is right on the money. These are pearls he's giving you here boys and girls. The man knows his stones. And if you haven't been to his website - get over there.
    samuraistuart likes this.
  12. David Martin

    David Martin Gold Member Gold Member

    Apr 7, 2008
    I wanted a flat stone and a finer surfaced side on my ceramic stone. I sharpen razors on this stone and use a guide setting on the lifted edge. I could see my straight not touching the stone in places. So, I corrected this malady on my stone. In doing so I learned a lot about
    the stone. Also, how edges are affected moving across a flat surface. Acquiring this knowledge I would not trade. It cost me some wear on my stones but gaining experience is never cheap. I'm glad I did it. DM
    Chris "Anagarika" likes this.
  13. samuraistuart

    samuraistuart KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Dec 21, 2006
    This afternoon I took some 60 grit and then 120 grit SiC powder on a glass plate to the Spyderco Fine stone. (I had previously attempted flattening and conditioning with a cheap fine diamond plate). I used marker to make a cross cross pattern on the surface just to see how out of flat it might be. It wasn’t bad at all. Older stone, previously diamond lapped.

    I only spent about 30 minutes or so on one surface. It wasn’t too out of flat at all, but it’s flat now! I’m in the process of finishing a new knife for a client in 61hrc 52100. Once it’s ready to sharpen, I’ll finish on this stone and report back. Can’t wait to try it!
    Last edited: Feb 21, 2019
    Chris "Anagarika" likes this.
  14. samuraistuart

    samuraistuart KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Dec 21, 2006
    Totally agreed. I’ve learned a lot from him when he started posting. I have a few Baronyx stones. I forget their names tho. I have the synthetic ruby stone. The super aggressive 60 grit green and black SiC stone. And the diamond/SiC stone (Mutt?). I don’t have the Arctic Fox yet. Would LOVE for them to do a higher grit SiC stone, like 1000 ANSI. Hard bond of course, for apexing. Something to try besides diamond plates for a more refined edge, especially on the harder and/or higher carbide % steels.

    And also David Martin and Obsessed With Edges. Much thanks to your contributions as well. Solidly good, and much appreciated, input.

    Heavy Handed too!
  15. FortyTwoBlades

    FortyTwoBlades Baryonyx walkeri Dealer / Materials Provider

    Mar 8, 2008
    In about a month or so I ought to have a little surprise along those lines. Not saying any more about it for now, though, other than it's just dandy for apexing! :)

    As far as names go, the ruby grit is the Bull Thistle blend, the black and green SiC is the Manticore blend, and the stone made from unsorted recycled grit (aluminum oxide, silicon carbide, and a little bit of trace diamond shed from the wheel that does the grinding which generates this waste material) is the American Mutt blend.
    samuraistuart likes this.
  16. Chris "Anagarika"

    Chris "Anagarika"

    Mar 7, 2001
    @FortyTwoBlades ,

    Respectfully disagree on the notion that stone not very flat is ok, as the free hand introduces more wobble. If the hand wobbles, would it would be better that the stone is 100% flat, so the only fluctuations is by the hand and nothing else. Statistically, the stone not very flat may cancel the effect on wobble but may also add to it, as it is going to be random.

    The dishing of waterstone on the other hand may help compensating hand wobble, at least the way I sharpen, observing my hand rocking motion.
    David Martin and annr like this.
  17. annr

    annr Basic Member Basic Member

    Nov 15, 2006
    Could not agree more. When I was old enough to realize that the stones and blade edges were not factory made “true” and switched to flat only sharpening media, all
    —or most—of my problems magically disappeared. (There are still problems related to steel, design, grind, etc., but are much simpler without some X factor variable I’m compensating for.)
  18. David Martin

    David Martin Gold Member Gold Member

    Apr 7, 2008
    My experience is; when starting from a flat surface, this helps toward producing cleaner bevels. DM
  19. FortyTwoBlades

    FortyTwoBlades Baryonyx walkeri Dealer / Materials Provider

    Mar 8, 2008
    If it's significantly out of flat, yes, that's a problem. If it's only a tiny bit, like in most cases, it really isn't. Most people aren't flattening their stones every single time they use them. Even relatively hard stones typically end up less flat than a lot of sintered stones are fresh from the factory after a single sharpening job. As in many things in life, dosage makes the poison. If it's way out of flat, then yes it obviously needs fixing. If you barely have any light peeking out under a straight edge laid on the stone (as is usually the case) then it's negligible and not in need of correcting unless you're doing something like razor honing or similar.
  20. ckdexterhaven


    Feb 16, 2019
    I just bought this used Spyderco UF in the German knife forum: https://translate.google.com/translate?hl=en&sl=auto&tl=en&u=http://kochmalscharf.freeforums.net/thread/1796/spyderco-uf

    In this thread it is described how it was flattened with DMT 120 and then made finer with DMT 325, Atoma 600, (probably Naniwa 1000), Naniwa 5000, Naniwa 10000, lapping film and 0.5 micron diamond spray.

    This is the edge the factory UF produced:


    This is the edge it then produced:


    The stone also got slower the finer it got.

    I am now flattening the other side and will bring up to around 6000 (I think a little finer than regular UF) so it can be used before the finer side.
    bucketstove likes this.

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