Ceramic stones wearing out after 6 months?

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general38

Joined
Nov 13, 2007
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Hi everyone. I brought a spyderco 600 grit 8 * 2 inch sharpening stone just prior to Christmas. Since then i have been sharpening probably 10 - 15 knives a week putting awesome edges on many different types of knives. It seems lately however that the stone has lost its ability to cut into the steel. I tried using Powdered cleanser and a scrubbing brush along with a nylon scourer to remove any metal to try and improve its cutting power. No luck. Its very painful to get an edge formed on a 58 - 60 grade steel where as when the stone was newer this was never a problem. Is this normal for ceramics? Spyderco claim their stone can be used day in/ day out but it does not seem to be the case here. Do i need to buy another stone or is there something i can do? Any suggestions would be appreciated.
 
general38 said:
Hi everyone. I brought a spyderco 600 grit 8 * 2 inch sharpening stone just prior to Christmas. Since then i have been sharpening probably 10 - 15 knives a week putting awesome edges on many different types of knives. It seems lately however that the stone has lost its ability to cut into the steel. I tried using Powdered cleanser and a scrubbing brush along with a nylon scourer to remove any metal to try and improve its cutting power. No luck. Its very painful to get an edge formed on a 58 - 60 grade steel where as when the stone was newer this was never a problem. Is this normal for ceramics? Spyderco claim their stone can be used day in/ day out but it does not seem to be the case here. Do i need to buy another stone or is there something i can do? Any suggestions would be appreciated.
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That is really weird. Granted, I haven't been using my stones so extensively as you, but I do not think this is normal. I'd try to contact Spyderco.
 
Sounds "burnished" (I think that is the term).

Have you tried using a diamond hone to resufave the flat, i.e. rub the surfave to expose fresh material.

Some of the newer steels can potentially wear the ceramic as much as, or more than, the ceramic wears the steel. Carbude or whatever in the steel being hard enough to do such wear.
 
orthogonal1 said:
Sounds "burnished" (I think that is the term).

Have you tried using a diamond hone to resufave the flat, i.e. rub the surfave to expose fresh material.

Some of the newer steels can potentially wear the ceramic as much as, or more than, the ceramic wears the steel. Carbude or whatever in the steel being hard enough to do such wear.
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You should check with Spyderco first. Seems that I read somewhere that if you lap their 'stones' it would invalidate their warranty.
 
they can be difficult to get real clean. before you do much make sure you have gotten them clean. Scrubbing with an ink eraser, SOS pad, and even a run through the dishwasher may help with a good cleaning.
 
I cleaned the stone using a dishwasher and powdered cleaner. However when I shine a bright light on the stone I can still see some pieces of TINY metal ingrained into the material. I tried sharpening my kizlyar using the same stone after a vigorous clean last night and after about 15 mins it was blunter than when I began (this knife normally sharpens up very easilyl). To relax I often sharpen knives and I like nothing more than a razor sharp edge (im a bit obsessed really) - I dont believe my technique to be at fault here because I can grind it using my DMT and bring the edge up but this is a course grind and i prefer using a medium grind before progressing to the fine grit. When I run my finger over the front of the stone it feels very smooth - almost too smooth. Thats why i had to ask the question if the stones eventually wear smooth. When i first brought this stone I could swipe perhaps 10 passes each side and the blade would respond, but now its very frustrating. The part number of the stone is SP320M.
 
The spyderco ceramice will break-in over time and become less abrasive(or just seem that way). To clean your ceramics use bar keepers friend and a scotch bright pad, don't use too much water you want the mix to be like mud to get the best results. I have had my ceramics for a long time and they still look like new and work just fine, also the brown ceramic is closer to 1000 grit.
 
I haven't tried this with Spyderco stones, but I've cleaned some generic ceramic stones by dunking them in Naval Jelly for a day. The stuff is usually used to dissolve rust. I was experimenting to see if it would have an effect on the coarseness of the ceramic. I didn't. But it did return them to bright white again, they were previously stained gray by sharpening, and never really looked clean until the acid treatment.
 
The bar keepers friend does almost the same thing as the naval jelly just a lot faster , it a chemical reaction plus its an abrasive, it only takes about 60sec. to go from cloged to clean.
 
I'm trying to find an alternative to barkeepers friend here in Australia. I have also contacted Spyderco to see what they say.
 
Thank you very much for your suggestion, I will order the cleanser and give it a try. If this works I will be exceptionally happy!
 
SOS pads are steel wool. Also try useing a steel wool pad instead of the nylon scrubbies.
 
To general38:

buy a japanese waterstone in similar grit range which is between 1000-2000 I think and use spyderco medium stone as a burnisher for touching up the edge. In Spyderco catalogue does say that "medium grit (brown) stones will wear out over time and repeated use".
 
Volkodlak said:
To general38:

buy a japanese waterstone in similar grit range which is between 1000-2000 I think and use spyderco medium stone as a burnisher for touching up the edge. In Spyderco catalogue does say that "medium grit (brown) stones will wear out over time and repeated use".
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The brown stone will wear but it will not wear out, it may need to be flattened over time but that's ture with any softer stone. Grit is also very different between american and japanese stones, I find it better to look at the micron/partical size because it will give you a more accurate measurement.
 
knifenut1013 said:
The brown stone will wear but it will not wear out, it may need to be flattened over time but that's ture with any softer stone. Grit is also very different between american and japanese stones, I find it better to look at the micron/partical size because it will give you a more accurate measurement.
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"Medium grit stones (brown) are closed-cell stones and will wear out over time and repeated use." this is direct quote from Spyderco 2007 catalgoue.
It also says fine and ultra fine grit stones won't wear out with usage or time.
I have had Spyderco pro file set for nearly a decade now and I can attest this is true. The fine ceramic file doesn't show any sign of wear at all while the medium file which I used more of the two lost its original cutting ability years ago. A couple of days ago I tried to resurface it with DMT coarse stone. I was working on it for some 10-12 minutes and it exposed some 80% of new surface which is somewhat better than that glazed surface but still not as good as original new surface as far as I remember.

Regarding the 1000-2000 grit range, I meant on japanese grit not american grit.
 
Regarding the 1000-2000 grit range, I meant on japanese grit not american grit.
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I understand, I was just saying its better to grade them in microns.

"Medium grit stones (brown) are closed-cell stones and will wear out over time and repeated use."
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The fine and ultra-fine grit stones are "close celled" (the particles that make them up are very dense) and will show little or no wear over time. the medium grit stones are "open-celled" (particles are less dense) and will wear only slightly over time. This is a quote taken directly from the paper that comes with the stones.
 
knifenut1013 said:
I understand, I was just saying its better to grade them in microns.



The fine and ultra-fine grit stones are "close celled" (the particles that make them up are very dense) and will show little or no wear over time. the medium grit stones are "open-celled" (particles are less dense) and will wear only slightly over time. This is a quote taken directly from the paper that comes with the stones.
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Apparently Spyderco wrote both. Anyway I remember that about "will wear only slightly" and practice has shown they wore out quite a bit more than just slightly...for sharpening you are better off with a good japanese waterstone which has similar result in terms of sharpness
 
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