Thread: Coti? Jnat??

So I've trying to resolve some of my ignorance of natural hones. I've gone through the library and post but still have broad gaps in my understanding.
It seems there are a several varieties. A coticle is from Belgium and contains garnets as cutting agents. Eshers is a brand name of a German, I believe, quartz stone but can mean the stone variety itself and chosera is actually a Naniwa synthetic. There are others but these are the ones I hear most often
Then there are Japanese stones. Several varieties but to keep it simple they are generally called jnats.
Now if that is reasonably correct. The brunt of my question is about slurry, slurry stones, something I think must be a slurry stone, nagura, and how do you use them?
Slurry is stone wear it seems, produced by honeing or by rubbing the hone with a slurry stone? How does one chose a slurry stone? Is it different than the base hone? Something I just read suggested someone was using a jnat and it seemed 4 or 5 different "nagura" stones. Whaaaaa?
Is there a newbies guide to this seemingly arcane bidness?
It also seems only a few natural stones use slurry. Slate, Scottish and Arkansas don't seem to. They are also mentioned less as well. Lower quality of the edge??
Thanks

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Natural razor hones in general and natural finishing stones in particular is too vast a subject to discuss in a single post. In my opinion the quality of the final edge will depend more on the hand using the hone than the hone itself. More info concerning naturals can be found here. Jnats, Tomo & Mikawa Nagura & Straight Razor Hones | TomoNagura.Com and also here (see the asano nagura link) Razors on Jnat just remember that these are opinions of the authors and nothing is written in stone. An Introduction to Japanese Hones, pt. 3

You can use slurry with naturals or synthetics. It speeds up the cutting process. to make slurry you wet the base stone with water and rub the slurry stone on the base stone until you get a cloudy liquid. As the stone dries out you add more water.They are usually the same as the base stone. This a very simple answer to that part of your question. You can look at natural hones as being in 3 categories. Course, medium and fine. There are many types of natural stones from all over the world. J- nats are from Japan. Coticules are only found in Belgium. Eschers are fine stones that were mined in one region of Germany. They are from the family of stones called Thuringians. Escher was the company that mined them. Are you thinking of using naturals? Do you currently hone? If so what stones do you have? Hope this helps. There is a lot to sort through. Good luck.

So, first understand that all natural stones are made in nature, over thousands/millions of years with no quality control. As a result, all natural stones will perform differently, even of the same type, some from one side to the other.

Using slurry is a technique, that in itself requires a learning curve, and depending on the slurry, stones and technique a large learning curve.

Lately it seems popular to slurry stones, that normally do not require slurry to perform in order to enhance or modify performance. Results are mixed.

With all naturals, as with slurry, results will vary depending on the experience and technique of the honer. Which is why, naturals are not recommended for new honers to learn on. They just introduce a host of more variables to the honing process.

While there are some broad guides to natural stone, (see the Library/ Maintaining Straight Razors/ Razor Hones), that give general information on natural stones, if you want to learn more detail, you will have to research each individual stone, of which much is written and published.

Bottom line is your result will vary, depending on the stone and your technique.

Learn to hone on synthetics, of which much is written and proven recommendations made.

Once mastered, then experiment with naturals. Quality synthetic stone of the same brand and grit will all perform equally, with predictable results.

As always, Euclid440 is spot on and it pays to heed his advice. For informational purposes, here is a brief description of my usual honing process with Japanese naturals that I emailed to a friend recently:

--

The basic premise is that you have only one large stone for honing (called a Toishi) and several different smaller stones (called Nagura) for raising slurry. These Nagura correspond to the different grit levels in synthetic hones or the progressive dilution of Coticule slurry. The four that are commonly used for sharpening razors are called Asano Mikawa Nagura and are from different layers of the same seam in a single mine (Mikawa). They are mostly white (Asano) and are formed from volcanic ash. From coarsest to finest they are called Botan, Tenjyou, Mejiro, and Koma, and are used in that order. Although more abrasive than the Toishi, they are softer in structure, and the slurry produced is mostly composed of material from the Nagura and thus white in color. Once you have worked through these four (usually 2 - 4 cycles of each type, washing the hone between types), the blade will be quite sharp and the bevels will have a hazy finish. To finish, you use a small piece of the same or similar stone to the Toishi, called a Tomo Nagura. This type of stone is from a different area of Japan and is sedimentary in nature. The slurry produced is the same color as the Toishi and starts off sharpening but breaks down into finer particles that polish and refine. The idea is to work Tomo slurry until it starts to break down (you can feel it change and it darkens at the same time) and then replace it until you have the edge as sharp as you want it. You then leave the slurry on the Toishi and work it until it is completely broken down, diluting as necessary to keep it from drying out. It will be very dark at this point and you can feel that it is basically no longer doing anything. At this point, you can wash the stone and razor to remove all traces of slurry and the do some final laps on a very thin film of plain water, generally 10 - 30 is sufficient. If you overdo it here, the edge can get harsh, but a single iteration of Tomo slurry and fewer laps on water will fix that.

Euclid is right...

My story is I started with only a coticule, I didn't listen to the advice to get a synthetic... well it took quite a long time to get great edges. I mean over a year to really nail an edge and even now just diluting with slurry is 50% depending on which specimen. Every time I asked for help I was given information that may or may not have worked with my particular stone. They weren't with me. They didn't have my stone.. so how can you really give advice for something you don't know? You can't you can only generalize for what works for your coticule..

I had to learn
A) how to hone a straight razor and
B) how to use slurry effectively

Both of these skills take persistence and time to learn and having no honing experience prior I was met with a lot of really poor edges.

I now have nothing to fall back on if an edge just won't respond to my coticule which is rather annoying because I would like to pull out my 4/8k (if I had one) and know that there is a 99% chance every time that my edge will be shave ready. I'm sure it would be much easier to go that way but everyone has to blaze their own trail.

If I went back in time I would learn how to use synthetics well because of how easy everyone says they are.

Slurry is just what is made from rubbing two stones together. Ground up little bits of the rocks.

You can mix and match or keep the base and slurry stone the same.

An arkansas stone finisher will absolutely not leave an inferior edge.

YMMV.

Thanks gentleman.
I've honed about a donzen razors. I've cleaned up some nicks. I've been honing knives since about 10. I've been honing razors on film with fine results. I just ordered a set of Nortons. I'll need a finisher at some point. I'm just mainly currious. From the posts I've read, it seems, naturals are a bit of vodoo in that there is some mad science going on. I haven't found much on how to use them. The chart in the library has been most helpful in explaining the different stones but nothing on jnats. and little on techniques used.
I'll have look at links posted.
Thanks again.

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Originally Posted by Clayglen

I haven't found much on how to use them.

Youtube.com

Unfortunately, there's no newbie guide. I've been recently learning about hones myself, and believe me when I tell you that there is a lot of information out there, and much of it is highly speculative.

The Jnat resources linked above should be a good start. For coticules, coticule.be seems to be the leading resource.

For empirical, objective information on hones and honing, Science of Sharp would be worth a gander. The author of the blog uses scanning electron microscopes and sophisticated measuring techniques to objectively analyze what hones and honing do to edges.

I'd place much more weight on the findings reported by the Science of Sharp than someone who swears by their "HHT 5 edge that gives the perfect BBS 3-pass shave" without any photographic or video evidence. Not to mention, with proper technique, an adequately sharp razor should almost, but not quite fully, get you a BBS shave in a single pass.

sqzbxr really gave you a pretty good break down. You say you've ordered a Norton stone, the 4/8 I'm assuming? The good news is the 8K is actually a finisher. I've been shaving off an edge that's been touched up on the Norton 8K (almost) exclusively for 2 months now. But wait, there's more! From the Norton 8K stone, you can move on to any natural finisher you like and completely skip the slurry process. Most* natural finishers are either a side step in fine-ness, polishing to about an 8000 grit level, or a slight upgrade polishing to around 10-12k level. This means you can completely skip the slurry phase and move on with pure water.

Slurry as advertised, abrades the edge faster. If your rock polishes like an 8K stone with pure water, using the same type of rock to build a slurry can make it perform like a 5-6K stone. Using a different kind of rock can drop this value further. This is useful if you only have a 1K stone, a finisher, and a few other smaller rocks to rub on the finisher. You can '2-stone' a razor start to finish. It is also quite interesting, and fun. But you can get by without it.

Focus on your 4/8 for now. When you've got that down, pick up a natural and use it without slurry. Then if you get curious, start playing around with a rubbing stone. Start with the minimum, and add variables later. Don't take too big a bite from the word jump.