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Thread: Ceramic kitchen knife, how to sharpen?

  1. #1
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    Ceramic kitchen knife, how to sharpen?


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    I bought a yoshi blade on a whim, and I was pleasantly surprised. It's very sharp.

    But, how do I keep it that way with the materials I have?


    Edge Pro Apex 4
    Smiths small diamond hone
    Strop with green compound

    Can someone tell me if it's ok to use the diamond hone and green compound on this ceramic knife? Thanks all.

  2. #2
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    never did, but from what i've been told when i asked, you can sharpen them only with diamonds, and you should avoid the coarsest grits. the lightest touch is required or you'll get microchips. if i where you i would buy the diamond stones and diamond tapes from edproinc.com, they are specificaly chosen for ceramic knives.

    hope this helps.

  3. #3
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    Quote Originally Posted by CrimsonTideShooter View Post
    I bought a yoshi blade on a whim, and I was pleasantly surprised. It's very sharp.

    But, how do I keep it that way with the materials I have?


    Edge Pro Apex 4
    Smiths small diamond hone
    Strop with green compound

    Can someone tell me if it's ok to use the diamond hone and green compound on this ceramic knife? Thanks all.
    I'd also recommend being VERY CAREFUL with the diamond hone. I have read some discussion here, along similar lines, about sharpening ultra-hard (and thin) blades with diamond hones. There's a real danger in chipping the edge, especially with coarse diamonds.

    As for the green compound, I'm betting it won't work. The green compound is chromium oxide, the ceramic blade is (I believe) made of 'alumina' (another term for aluminum oxide). Assuming that to be the case, aluminum oxide is actually a bit harder than the chromium oxide. So, I don't think the green will touch it. For that matter, I don't even know if a ceramic blade actually needs to be stropped. I don't think it tends to form any burrs. You might have some luck using diamond compound (paste/spray), to polish the edge a bit.

    Edit:
    Just looked at a description of the Yoshi Blade on Amazon, and it say's it's made of 'diamond hard Zirconium Oxide'(). I'm betting the green compound probably won't touch that, either.
    Last edited by Obsessed with Edges; 04-04-2011 at 09:16 PM.

  4. #4
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    According to their (FAQ) section, it should never need sharpening.

  5. #5
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    Quote Originally Posted by big wes View Post
    According to their (FAQ) section, it should never need sharpening.
    No doubt a great marketing pitch, but we as knife enthusiasts know that there is no blade that "never needs sharpening".

  6. #6
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    Quote Originally Posted by CrimsonTideShooter View Post
    No doubt a great marketing pitch, but we as knife enthusiasts know that there is no blade that "never needs sharpening".
    I understand.

    To a true knife nut, the phrase "never needs sharpening" sounds more like a challenge. Just have to find out if it can be MADE sharper, regardless...
    Last edited by Obsessed with Edges; 04-05-2011 at 01:50 PM.

  7. #7
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    No doubt a great marketing pitch, but we as knife enthusiasts know that there is no blade that "never needs sharpening"
    Yeah I love to sharpen my knives, I get great enjoyment from it, but that being said, on one of those TV specials I'd send it back to them telling them it didn't hold up to all their hype and see what they'd do about it.

  8. #8
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    Everything I have ever read about ceramic blades says "No touchy" send back to factory for sharpening. Obviously they have something back at the factory that sharpened the blade, what that is I guess is the question. If a "steel" can sharpen a steel knife I wonder if a ceramic can touch up a ceramic? If it was my knife, thats where I'd start. Diamonds would not be my first step.

    According to eHow-
    Purchase a silicon carbide wheel or stone to sharpen your ceramic knives--if you don't want to use a diamond stone. Silcon carbide stones are made of a softer aluminum oxide and may not be as abrasive. If your diamond blade leaves any scratches, the silicon carbide wheel will remove any fine scratches left by the diamond blade.
    Buff with a paper wheel.
    Last edited by RubiconSS; 04-05-2011 at 02:26 PM. Reason: eHow

  9. #9
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    Knife steels work mainly to scrub burrs off, or re-align the edge on a knife. Not much metal removal (sharpening) involved there.

    I tried, on a whim, to see if aluminum oxide wet/dry sandpaper would lap a ceramic hone (also aluminum oxide, aka 'alumina'). Didn't phase the hone or the sandpaper. Sort of like rubbing two pieces of glass together. Lots of effort, with no noticable effect. I don't think ceramic on ceramic will do much.

    I have seen a reference on the web, about using silicon carbide wet/dry sandpaper to sharpen a ceramic knife. Don't know specifically what type of ceramic, but the SiC might be a tad harder than some ceramics, at least. That might be worth some 'experimentation'.

  10. #10
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    I'll try it and post back with the results.


    Anyone wanting to play around with a ceramic blade should pick one of these up. I got mine at best buy for 12 dollars. Out of the box it was nearly as sharp as the knives that come off my edge pro, and that's saying something! It would slice TP cleanly; never seen that with a production knife.



    Quote Originally Posted by Obsessed with Edges View Post
    Knife steels work mainly to scrub burrs off, or re-align the edge on a knife. Not much metal removal (sharpening) involved there.

    I tried, on a whim, to see if aluminum oxide wet/dry sandpaper would lap a ceramic hone (also aluminum oxide, aka 'alumina'). Didn't phase the hone or the sandpaper. Sort of like rubbing two pieces of glass together. Lots of effort, with no noticable effect. I don't think ceramic on ceramic will do much.

    I have seen a reference on the web, about using silicon carbide wet/dry sandpaper to sharpen a ceramic knife. Don't know specifically what type of ceramic, but the SiC might be a tad harder than some ceramics, at least. That might be worth some 'experimentation'.

  11. #11
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    Quote Originally Posted by rubiconss View Post
    Everything I have ever read about ceramic blades says "No touchy" send back to factory for sharpening. Obviously they have something back at the factory that sharpened the blade, what that is I guess is the question. If a "steel" can sharpen a steel knife I wonder if a ceramic can touch up a ceramic? If it was my knife, thats where I'd start. Diamonds would not be my first step.

    According to eHow-
    Purchase a silicon carbide wheel or stone to sharpen your ceramic knives--if you don't want to use a diamond stone. Silcon carbide stones are made of a softer aluminum oxide and may not be as abrasive. If your diamond blade leaves any scratches, the silicon carbide wheel will remove any fine scratches left by the diamond blade.
    Buff with a paper wheel.
    "Silicon carbide stones are made of a softer aluminum oxide" (???)

    If so, it wouldn't be a silicon carbide stone. It would be an aluminum oxide stone. Two completely different compounds (chemically & physically).

  12. #12
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    Quote Originally Posted by Obsessed with Edges View Post
    "Silicon carbide stones are made of a softer aluminum oxide" (???)

    If so, it wouldn't be a silicon carbide stone. It would be an aluminum oxide stone. Two completely different compounds (chemically & physically).
    Dunno. Was a copy and paste quote from sHow.

  13. #13
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    Quote Originally Posted by rubiconss View Post
    Dunno. Was a copy and paste quote from sHow.
    I didn't intend to pick on you. If it came across that way, I apologize for that. My remark was directed at the eHow article itself. I saw that article, and the more I looked at it, the more ambiguous & confused it seemed. He mentioned marks being left by the 'diamond blade' (again, ???), and using the silicon carbide stone/wheel to remove them. I'm assuming the author intended to point out that the silicon carbide was 'softer' than the (originally recommended) diamond hone, but I think he's confused about what a 'silicon carbide' stone is made of. Either that, or it was a typo or momentary brain-fade. Still trying to figure out what he was really trying to convey.

  14. #14
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    Cubic Zirconia usually are used as mini stones to embellish the jewellry if using real diamond is too expensive. I think only diamond can sharpen your knife, but that's just a guess.

  15. #15
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    Last I looked into it, these blades were made of transformation toughened Zirconia. This is a mixture (alloy if you like) of Zirconia and Alumina. The addition of the Alumina in the proper proportion allows for the transformation that increases the toughness. Even with this, it's still 1/10 as tough as steel. From the research I've read on it, the edge must be polished to a very high finish or the scratches are enough of a flaw to cause fracture when used for cutting. It does not form a burr, and a coarse edge will not work on it. It just breaks off.

    http://www.youtube.com/watch?v=JFnT5INymiY

    Here is some info on the ceramic knives, though take it with a grain of salt. It's a marketing video after all.

  16. #16
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    Quote Originally Posted by Obsessed with Edges View Post
    I didn't intend to pick on you. If it came across that way, I apologize for that. My remark was directed at the eHow article itself. I saw that article, and the more I looked at it, the more ambiguous & confused it seemed. He mentioned marks being left by the 'diamond blade' (again, ???), and using the silicon carbide stone/wheel to remove them. I'm assuming the author intended to point out that the silicon carbide was 'softer' than the (originally recommended) diamond hone, but I think he's confused about what a 'silicon carbide' stone is made of. Either that, or it was a typo or momentary brain-fade. Still trying to figure out what he was really trying to convey.
    Thank you OwE, no offense taken my friend. I too thought the HowTo was a bit clugey. It almost seemed to more a list of steps 1-10 with a progression starting with the extreme and ending with "simply send it back and let them sharpen it". Not much help perhaps. The one entry that seemed to stick out was the one we both noticed. All very mysterious these eHow HowTo YouDo IWill help you websites.
    I am off now to research the At Home Labotomy.com site

  17. #17
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    cts, do you have a dremel tool with a mandrel for small cut off discs? i have a few really fine diamond discs that i have been using on a boker ceramic knife that was as dull as a butter knife when i got it. now it has a decent working edge. i would part with 1 if you want to give it a try. pm me your addy and i'll put one in an envelope and send it to you. they are the size of a quarter.
    I offer professional knife sharpening 40 years of experience, 22 with the paper wheels. $1. per inch for a v edge, $2 for a convex. I sharpen all edges & "Ti" knives, serrations. plus i do regrinds. Check out my website.http://sites.google.com/site/richardjsknives/Home

  18. #18
    Quote Originally Posted by Obsessed with Edges View Post

    To a true knife nut, the phrase "never needs sharpening" sounds more like a challenge. Just have to find out if it can be MADE sharper, regardless...
    Challenge accepted by this tool:

  19. #19
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    LOL. He said he sharpened a knife with the Samauri Sharp. I predict the ceramic wins just on that basis. Well, after watching, I was wrong, again, today...
    Last edited by me2; 04-08-2011 at 04:01 PM.

  20. #20
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    Putz tries to saw through wood with a CERAMIC, FINE-EDGED knife... jeez. The scary part is, I'm still watching >_>

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