Recommendation? Ceramic stone question

Discussion in 'Maintenance, Tinkering & Embellishment' started by ktataragasi, Jun 23, 2020.

  1. ktataragasi

    ktataragasi

    133
    May 26, 2019
    Hello all. I have been getting into some free hand sharpening and I have had and been using some diamond plates. I have course, medium, fine and super fine diamond plates. I find that even the super fine stone leaves a super toothy edge.

    I have been looking at the Spyderco 302 series stones and I am wondering if it is worth getting the medium ceramic stone or just go for the fine and maybe ultra fine stone with what I already have? Any recommendations?
     
  2. FortyTwoBlades

    FortyTwoBlades Baryonyx walkeri Dealer / Materials Provider

    Mar 8, 2008
    The fine and ultra fine are the same stones but the fine is as-fired finish and the ultra-fine has been surface-ground. The surface conditioning of sintered ceramics has a large effect on their performance, and in general you should be using them for final stages of honing only, to minimize the wear on the surface layer of abrasives since they do not shed grit and require periodic surface conditioning to expose fresh grit.
     
    mycough, Hurrul and kreisler like this.
  3. ktataragasi

    ktataragasi

    133
    May 26, 2019
    Thanks for the info.

    I am able to get my knife to chave off of the course dmt. Just wondering if the medium ceramic is already covered by my super fine stone or if it would still help refine the ege a bit more and maybe be a better touch up stone.
     
  4. Barmaley

    Barmaley

    131
    Dec 31, 2016
    I heard somewhere on youtube that Spyderco ceramic stones never need service and stay as new despite if use. Is not it true? Based on previous advice I was trying to change grit of generic ceramic rods which I bought on Ebay and they came coarse. I used Silicon Carbide sand paper first 400 grit and then 180 grit to re-surface rods. They became very smooth like extremely fine, but they are let me say became dull. Before sand paper treatment they were cutting fast and visible grey markings in the rods were developed immediately, now they are like not cutting almost at all. Was it wrong type of ceramic (not-serviceable) or I was doing something wrong?
     
  5. UncleBoots

    UncleBoots Gold Member Gold Member

    42
    May 27, 2020
    How is surface conditioning done on these stones?
     
  6. UncleBoots

    UncleBoots Gold Member Gold Member

    42
    May 27, 2020
    I'd definitely go for the medium stone. It's not really a coarse stone, unless you compare it to the others. I have all three, and I'm happy to have them, but if I could only have one, it would be the medium. It's in a nice sweet spot for touching up blades.
     
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  7. FortyTwoBlades

    FortyTwoBlades Baryonyx walkeri Dealer / Materials Provider

    Mar 8, 2008
    Lapidary diamond on a piece of plate glass (or stone tile if you can get it at comparable pricing) with a little water and figure-eight motions. The grit of the diamond you finish with will determine the surface finish. You can also use a diamond plate to abrade the surface, but that yields less consistent results and takes much longer if you're trying to do anything more than just taking off the very surface layer of grit to expose fresh cutting surface.

    As the surface layer of abrasive grains dull from use, the stone will begin to merely burnish your edge without actually removing steel effectively, and will be prone to forming a gummy wire edge instead of a nice crisp apex.
     
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  8. JJ_Colt45

    JJ_Colt45 Gold Member Gold Member

    Sep 11, 2014
    The Spyderco Ceramic stones will finish much finer than what they rate so medium may surprise you... but it depends on what steels you are wanting to sharpen whether it would be a stone I would use or recommend.
     
    Last edited: Jun 23, 2020
  9. Alberta Ed

    Alberta Ed

    Jun 29, 1999
    Stick with the DMTs. All you really need.
     
    MTHall720 likes this.
  10. FortyTwoBlades

    FortyTwoBlades Baryonyx walkeri Dealer / Materials Provider

    Mar 8, 2008
    Sintered ceramics can be lovely finishing stones, and much more pleasant to use than extra-fine diamond. They're extra good for light touchups and final apexing, as well as final polishing of push-cutting edges. The question of whether they're needed or not depends on context, but I'd personally never go back to not owning at least a single sintered ceramic stone for the circumstances in which they really shine.
     
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  11. Backyard

    Backyard

    107
    Jul 19, 2019
    Have you tried stropping to rid the toothy edge? I find I can strop right after the fine and get a very smooth edge if I want.
     
    MTHall720 likes this.
  12. Craig James

    Craig James

    128
    Oct 30, 2018
    FortyTwo, where would you put the equivalent grit ratings, whilst appreciating that sintered ceramics do not have a grit rating in the true sense of the word?

    I tend to finish my vegetable slicers at 6k (King) and have been considering the F or UF for touch ups rather than taking the back to the water stone

    thanks
     
  13. David Martin

    David Martin Moderator Moderator Gold Member

    Apr 7, 2008
    I've finished my Spyderco ceramic stone finer on one side and I would say it gives about a 2K grit ANSI. Which I don't use much except for
    my shaving razor. DM
     
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  14. Barmaley

    Barmaley

    131
    Dec 31, 2016
    As I understand Spyderco uses two types of ceramic for their stones: one for fine and extra fine and another for medium. What is the difference in the ceramic used for in them? It is possible to re-surface medium stone to become fine or fine stone to medium grit?
     
  15. FortyTwoBlades

    FortyTwoBlades Baryonyx walkeri Dealer / Materials Provider

    Mar 8, 2008
    I honestly don't like using grit ratings as a reference point because grit is only one variable in the finish produced and you can have technically coarser stones that will produce finer polishes than higher grits. Sintered stones use a mix of grain sizes that aid in the sintering, with the bulk of the material being around 3mµ in size, but they function more like a file. So it's like asking what the different grit ratings of a file are--it just doesn't work that way, and a given stone of a given grit may produce a different finish than a stone of equal grain size but different binder, density, bond strength, and abrasive type. However, you could say that the medium is a good choice for general utility cutting while the fine and ultra-fine are suitable for woodworking and straight razors. The medium, if used on straight razors, would be a good intermediary between setting a fresh bevel and going up through polishing grits.
     
    Last edited: Jun 24, 2020
    Craig James likes this.
  16. Spyderco's own Sal Glesser has mentioned, years ago, they use the exact same raw grit (type & size) for each of the medium, fine and UF hones. The main difference with the brown/grey medium is the binder used and maybe the firing/sintering process for that specific hone. Otherwise, the differences in working 'grit' rating are mainly about the final surface finishing of each one. The Fine & UF hones would be otherwise identical, save for the final surface finishing for each.

    The medium can be lapped or refinished to a finer working surface, even as fine or finer than the stock Fine or UF hones. Many have done so, including myself. I don't know if anyone has tried refinishing one of the finer hones to something coarser; but I see no reason why that couldn't be done as well. It's tricky, though. To go coarser, some very coarse lapping grit must be used (many use something like 60/80 SiC grit for this). It's real easy to unintentionally make the surface finish a LOT finer than was planned, if the lapping grit isn't sufficiently coarse as compared to the desired outcome (lapping with 60/80-grit loose SiC to emulate something like the factory medium grit, in other words).
     
    Last edited: Jun 24, 2020
    kreisler likes this.
  17. FortyTwoBlades

    FortyTwoBlades Baryonyx walkeri Dealer / Materials Provider

    Mar 8, 2008
    Different carriers and firing process for the medium, but same actual abrasive grains. Not quite the same as binder, but the carrier aids in generating the desired structure in the end product. The abrasive grains are actually fused in sintering and that's what holds it together. :)
     
    Obsessed with Edges likes this.
  18. Craig James

    Craig James

    128
    Oct 30, 2018
    Thanks FortyTwo, fully understand the processes involved in sintering as a materials engineer and the impropriety in referring to them with a grit rating but was looking for some sort of equivalency in finish as a reference which you have happily provided.

    Cheers
     
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  19. ktataragasi

    ktataragasi

    133
    May 26, 2019
    I do enjoy an edge that has some bite to it but is still smooth when slicing through paper and stuff. I have heard the medium is good. Do you think the medium would refine the edge off of my super fine dmt? How does the fine compare?

    I have a range of steels. 20CV, S30v, S35vn, 14c28n, 8cr13mov, some carbon steels/case cv.... So a bit of everything.

    I have been messing with pressure trying to go as light as possible on the last few finishing passes with decent results but I guess I'm wondering if the ceramics wouldn't be better for touch-ups.

    I do a few final strokes on a strop. I can easily get a shaving edge but when slicing media I just notice a certain amount of drag. I am fairly new to hand sharpening so maybe it is just me needing to learn lighter pressure. I can get a shaving sharp edge off of even the course stone though so I don't think I'm off to a bad start.

    I guess I just don't know what to expect going from diamond to ceramic. Thanks everyone for the advice so far. I'm still not sure what direction to go in...
     
  20. ktataragasi

    ktataragasi

    133
    May 26, 2019
    Also as a follow up question to those who suggested just using a strop after the dmt what micron do you recommend for that?
     

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