Thread: How much slurry on a coticule?

Mmmm... Nice wide bevels perfect for a coticule with slurry. See I didn't go off topic
They are only £10 ish over here too - thats bloody good for a tidy knife.
Thank you.

Originally Posted by Bart

Many ways to skin a cat.

With slurry, a coticule cuts very fast. The result is very smooth, but the free floating garnets in the slurry also affect the very tip of the edge, by "micro-rounding" it. This effect is more severe with a very dense slurry, than with a thiner slurry. Normally the slurry needs to have the consistency of coffee milk. But do note, that the resulting edge will only shave marginally.

With water, a coticule cuts very slow. It excels in polishing grit marks of another hone, but once it hits the bottom of a given scratch pattern, it is much to slow to do any further refining of the edge.

For this reason, a coticule with water cannot improve much on the edge formed by a coticule with slurry. The slurry edge is already smooth, and the water-honing really is way to slow.
To put this differently: if you take the sharpest edge you can get of any synthetic brand 4K hone and you polish that on a coticule with water, you'll end up with a much sharper razor than when you would include a slurry session before the water session.

Conclusion: if you want to use the coticule as a finisher after a progression on coarser hones, then use it only with water.

There's a method for circumventing the slurry-water problem, which allows for honing a razor on nothing else but one coticule, but that requires a secondary bevel, which is a more advanced technique.

Best regards,
Bart.

Would a good 4k be a blue belgian?I am curious because I just tried sharpening my le grelot with slurry and then with water. The edge looks real nice under a microscope but it won't cut hairs at all.So, what you are saying must be true. I am going to try using my Norton 8k then go to the coticule with water only next. I don't have a blue belgian and really don't want to hit the norton 4k again. Hopefully this works. Supposedly my B&B le grelot is very hard metal.

Originally Posted by zenshaver

Would a good 4k be a blue belgian?I am curious because I just tried sharpening my le grelot with slurry and then with water. The edge looks real nice under a microscope but it won't cut hairs at all.So, what you are saying must be true. I am going to try using my Norton 8k then go to the coticule with water only next. I don't have a blue belgian and really don't want to hit the norton 4k again. Hopefully this works. Supposedly my B&B le grelot is very hard metal.

First off, allow me to state that I am totally opposed against rating the Belgian hones with any given grit-number. The coticule has a median particle size of 15 micron. A blue has a median particle size of 20 micron. A DMT D8E (1200 mesh) has a particle size of 9 micron. Go figure. Anyway, due to their elliptical garnets, Belgian hones leave a rather smooth, wavelike scratch pattern, completely uncomparable to the acute scratch pattern of synthetic hones. Rating the blue 4K and the coticule 8K (or 6K and 10K for that matter), IMHO has caused more confusion on this forum than it offered a true understanding of what these hones can offer.

That said, the blue does display the same "slurrydulling" effect as the coticule, BUT to a far lesser degree. It really works great as a mediator between the above mentioned DMT-E and a coticule with water. As long as you use a rather thin slurry, and add an occasional drop of water before it becomes too dense. If it works equally well between an Norton 4K and a coticule with water, I 'd guess so, but, not owning a Norton, I can't back that up with actual first hand experience.

I think the biggest caveat in honing, is not doing enough work at the lower grit hones. The Belgian blue with slurry and the coticule with water are, in conjunction with hard razor's steel, slow polishing hones. If the edge is still blunt when leaving that Norton 4K, you'll end up with nothing more than an awesomely polished, but ever so blunt, edge.

My advice is to always do light strokes and stay on the Norton 4K till the razor shaves armhair extremely well. (personally I do a crude version of the HHT, to make sure I hit a good level of keenness at bevel setting stage) Only then, proceed to the Norton 8K, for about 10 laps or so. Then about 70 on the coticule with water. A double stropping session on clean leather. And a shave test.

Hope this helps. Please inform us about your results?

Best regards,
Bart.

Well, I tried going on my norton 8k with about 20 laps or so then went to the coticule for about another 20. My shave is better but it still needs work. My DOVO tortoise is still better. I imagine the DOVO is softer steel so would be eaiser to sharpen.I haven't really been doing the hair test so I am probably just polishing a dull edge that is slowly getting sharper. I don't have any arm hairs per se. So I try to use my stomach/chest hair and that doesn't work as well. I would have to be one of those guys with small blonde hairs on his arms.I am going to have to get serious here and go back to the 4k and check against my stomach/chest hairs.What you are saying all makes sense though. If it is not sharp on a 4k then it won't be sharp with a finer stone.

Thanks

I agree that most likely you need some additional work on the 4K.
But either way, 20 on the coticule (with water) is not enough, in my experience.
You need at least 50 strokes back and forth. 70 would probably be better. 100 won't hurt. If you keep the pressure light, there's no risk of overhoning on the coticule (a inherent ever so slightly rounding of the edge seems to prevent that, maxing out the level of sharpness, regardless how many strokes you do)

In the absence of arm hair to do any testing, you can learn to perform the TPT (Thumb Pad Test).
It's a bit more challenging to master, but once learned it's a very quick and reliable test to assess for sharpness. The idea is to feel for sharpness with the tip of your thumb. This sounds more scary than it actually is. Hold the razor by the tang in your right hand, the blade up and the edge facing to you. Place the fingers of your left hand behind the spine, as if you were going the grab the blade. Now, gently put your the fingerprint of your thumb against the edge. It won't cut your thumb anymore as it cuts your facial skin when you only touch it. Slowly slide your thumb a few mm along the edge, as if you were attempting to slice into your thumb. A truly sharp edge will exert a sticky, dragging sensation, as if it was covered with caramel. You should always probe the entire edge, 'cause during honing it's not unlikely that certain parts of the edge reach full keenness before others.

If you really want a fool proof method, without a risk of overhoning, without a need for testing, but with the risk to remove more steel than strictly necessary, here's a suggestion. Seasoned honemeisters might hate this.
(dislaimer: A good X-stroke on a flat hone is important, smiling razors need a rolling X-stroke)
Hone on the coticule WITH slurry till the slurry turns grey, as clear evidence of steel removal. Hone till the edge shaves armhair, or in absence of that, hone a brainless 100 laps.
Let's asume now that in most cases a proper bevel is set.
Hone 20 laps on the Norton 4K, to refine the typical slight roundness that a coticule with slurry leaves. Hone 10 laps on the Norton 8K, for further refinement. Finish with 100 laps on a coticule with water. Strop and shave.

Best regards,
Bart.

Originally Posted by Bart

First off, allow me to state that I am totally opposed against rating the Belgian hones with any given grit-number. The coticule has a median particle size of 15 micron. A blue has a median particle size of 20 micron. A DMT D8E (1200 mesh) has a particle size of 9 micron. Go figure. Anyway, due to their elliptical garnets, Belgian hones leave a rather smooth, wavelike scratch pattern, completely uncomparable to the acute scratch pattern of synthetic hones. Rating the blue 4K and the coticule 8K (or 6K and 10K for that matter), IMHO has caused more confusion on this forum than it offered a true understanding of what these hones can offer.

That said, the blue does display the same "slurrydulling" effect as the coticule, BUT to a far lesser degree. It really works great as a mediator between the above mentioned DMT-E and a coticule with water. As long as you use a rather thin slurry, and add an occasional drop of water before it becomes too dense. If it works equally well between an Norton 4K and a coticule with water, I 'd guess so, but, not owning a Norton, I can't back that up with actual first hand experience.

I think the biggest caveat in honing, is not doing enough work at the lower grit hones. The Belgian blue with slurry and the coticule with water are, in conjunction with hard razor's steel, slow polishing hones. If the edge is still blunt when leaving that Norton 4K, you'll end up with nothing more than an awesomely polished, but ever so blunt, edge.

My advice is to always do light strokes and stay on the Norton 4K till the razor shaves armhair extremely well. (personally I do a crude version of the HHT, to make sure I hit a good level of keenness at bevel setting stage) Only then, proceed to the Norton 8K, for about 10 laps or so. Then about 70 on the coticule with water. A double stropping session on clean leather. And a shave test.

Hope this helps. Please inform us about your results?

Best regards,
Bart.

yeah, that confirms so much of what i have been thinking. thanks