Thread: Friable grit stones

Time's been short, so I've not posted on several questions about naturals.

Friables (thuri/escher & Jnats) are spoken of as having desireable properties because the grit breaks down into finer particles, giving a finer finish as the slurry gets worked.

So either this grit breaks down in a very few (10?) strokes, or there's a disconnect in the honing discussions on their use. '10, no more than 20 strokes' etc. Can the grit breakdown happen that fast, or do the short-strokers (not meaning disrespect - they get results) bypass the finer stages of particle breakdown because the stone is so fine to begin with? Would it not be better w/ a period (some number of strokes) applied to break down the grit further?

I'd appreciate your thoughts here.

I assume you're referring to finishers. Jnat finishers are too hard to break down in 10 strokes but the chalky Nagura used with them breaks down plenty in about 30 back n forth strokes. In any case lot more laps in the process than 10 or 20 if you use Nagura.
OTOH if your edge is nearly there, 15 or so laps on plain water can finish a razor but won't be no friable slurry involved or at least not easily visible to the naked eye.

Hard finishing Jnats will take very long time to break down. The trick is to use softer tomonagura and let the grit be refined between the bevel and the base hone surface, this happens pretty quickly with the correct tomonagura.

ive heard people say that thuringians and PHIGs have friable grit, but im not so sure.. anyone else find this to be so?

All, Thank you for your kind help.

Onimaru - As you might guess - I've continued the path started by correspondence w/ So - using just the Atoma 1200 for slurry. The whole Tomo world is new to me. While I've gotten pleasing results from little slurry - quite quickly, any edge that's the least bit cranky has been helped by alot of circles & strokes while diluting the slurry. When I started w/ the Asagi, you mentioned mostly using as finisher only, w/out nagura. I don't know if that's still your preferred method or if you think getting smarter about the TomoNaguras would be a good thing to pursue.

Stefan - as you see from above, I'm not smart at all about Tomos. It would make sense that a soft, fine nagura would accomplish the refinement faster than the hard, native grit of the stone.

EZ: That's what I've heard about Thuris also, but never hear any reference to the breakdown in the discussions of using the thuris. This is part of what prompts the question. I suspect the grit does break down, and probably faster than the hard jnats. What makes me think this is that the stones are more soft than the hard jnats, and experience w/ one low grit black thuri. It has a fairly repeatable track record of starting w/ a set bevel and milky slurry and taking it to 8-10k level of sharpness. 'Seems to follow the progress of the 'one stone' method, though it doesn't take much deliberate dilution to get fine.

Again, Gents, I appreciate your thoughts.

Originally Posted by pinklather

Onimaru - As you might guess - I've continued the path started by correspondence w/ So - using just the Atoma 1200 for slurry. The whole Tomo world is new to me.
While I've gotten pleasing results from little slurry - quite quickly, any edge that's the least bit cranky has been helped by alot of circles & strokes while diluting the slurry. This can be problematic steel or honing probs earlier in the progression ie bevel set or not enough refinement somewhere in the progression.
When I started w/ the Asagi, you mentioned mostly using as finisher only, w/out nagura. I don't know if that's still your preferred method or if you think getting smarter about the TomoNaguras would be a good thing to pursue.

Are you finding a need for tomo or just wanting to experiment ? The Atoma 1200 simplifies the honing process a lot if you're jumping from a high grit synthetic , 8-12k. If you want to replace the synthetic scratch pattern on the bevel with that of the Jnats then you may have to spend a bit of time with slurries depending on when you leave the synths. It is mostly a cosmetic change but as you've found you can also correct a few earlier sins.
I think I originally suggested you try just water to see what your stone did to the edge that way. Remember, a lot of guys can shave off a Norton 8k so how much or what type of improvement are you after ? Probably that elusive 1-2% I not sure what my preferred method is as sometimes I use a light slurry or no slurry, just water & sometimes I do 5 or 6 strokes on my Asagi totally dry a la barber hone.
Maybe it's just about knowing when to stop honing.

I LOVE your questions, Oni. Abductive (as opposed to inductive/deductive). Why is the question an issue in the first place?

The question comes from the way the properties of the stones are discussed vs how their use is described. Put another way: if we don't make use of grit breaking down and providing a finer finish, why do we consistently speak of grit that breaks down? Its has confused me in the past, and likely has confused others. Some discussion of working jnat slurry is mentioned from time to time, but not the thuri/escher. At the 9/11 NW meetup in Spokane, the honorable Sixgunner demonstrated the jnat finish and described a moderately extended set of strokes as being done just to break down the grit. That was the only time I've heard it mentioned explicitely, other than some discussion on other forums.

'Leads me to believe that grit break-down is mostly unused - for whatever reasons. Maybe its not needed because the stone it comes from is adequate to do the job without the extra steps & strokes, or that few blades actually need the extra step.

Again, Gents, I appreciate your kind help.

Originally Posted by pinklather

I LOVE your questions, Oni. Abductive (as opposed to inductive/deductive). Why is the question an issue in the first place?

The question comes from the way the properties of the stones are discussed vs how their use is described. Put another way: if we don't make use of grit breaking down and providing a finer finish, why do we consistently speak of grit that breaks down? Its has confused me in the past, and likely has confused others. Some discussion of working jnat slurry is mentioned from time to time, but not the thuri/escher. At the 9/11 NW meetup in Spokane, the honorable Sixgunner demonstrated the jnat finish and described a moderately extended set of strokes as being done just to break down the grit. That was the only time I've heard it mentioned explicitely, other than some discussion on other forums.

'Leads me to believe that grit break-down is mostly unused - for whatever reasons. Maybe its not needed because the stone it comes from is adequate to do the job without the extra steps & strokes, or that few blades actually need the extra step.

Again, Gents, I appreciate your kind help.

I use grit break down on Jnats al lthe time, the only way to refine the edge to best possible outcome.
I have no idea about Escher /Thuri, I have not heard the biggest proponents say anything like that although I have heard some people mention. It is fairly easy to test IMHO. Grab a razor finish to 10-12k then grab a thury/ Escher and start honing on it, check with a scope every 20 strokes and see how the scratch pattern is changed. Repeat the same process with slurry for the same number of strokes and compare the differences. You have to make sure you re doing enough strokes to allow the thury slurry to be well worked.

Being friable and wearing are two different things. Friable really refers to something like sandstone which will come off in your hand when you rub it. Rocks that slowly wear down is just wearing down not friable. As to the breakdown it's a matter of if your talking a mineral or a rock and how hard it is and what cements it together and it's components. A mineral like quartz or beryl ain't gonna break down (practically speaking) because it's too hard in relation to steel. Once you know the variables you can predict what's going to happen pretty easily.

Originally Posted by pinklather

At the 9/11 NW meetup in Spokane, the honorable Sixgunner demonstrated the jnat finish and described a moderately extended set of strokes as being done just to break down the grit. That was the only time I've heard it mentioned explicitely, other than some discussion on other forums.

You haven't heard more about it because I gave up on trying to explain it over and over again, there are certain things that I find, I post, and I speak about it, and it falls on deaf ears so after that I just continue to do what I have found to work on the 1000's of razors I hone and smile... (if you were to search it out you will find several references that I have made to it)
I actually no longer use my J-nat with clear water, I always leave a slight bit of the old slurry on it and finish to damp,,, I have read of other J-nat users doing the same with Sushi Knives...

One thing I have said for a few years now is that we don't use enough pressure at the finishing stage to break down the slurry when honing Western style razors, other people are finding out there might be some substance to this.. One of the other senior members is experimenting with Corticule slurry break down and is finding basically the same outcomes.. He is working the slurry much much longer with the Slurry stone before he begins, to break down the Grit first...
I found much the same when using the Coticule as a pre- finisher for Kamisori the resulting haze finish is much nicer then what you would find when diluting out the same Coticule on a Western style razor...

Rob keep working the slurry breakdown you will find Gold if you dig deep enough...