Thread: Slurry Dulling

Firstly, i have no experience with J-Nats.
Secondly i use slurry as part of a progression from the same stone (Escher) slurry to water only. Same razor gets refreshed on the same stone with water only. At that point if you use slurry my guess would be that you run into "Slurry-Dulling" when your actually just wasting a precious stone. The key is the knowledge as to when the razor needs refreshing.

I hear ya...
My limited experience take with artificial stone made to slurry...

The pressure on the edge is multiplied by lots because of the small surface area of the edge... if you multiply this pressure more by floating the edge on a squishy mud, which consist of binding materials and abrasive particles and the particles doesnt move out of the way, but get trapped in between the edge and the stone because the medium is not as viscous as mostly water... then those little particles might do damage to a very fine edge... because you dont have a flat evenly abrasive surface, but a few with a few particles sitting proud and not getting out of the way...

Originally Posted by gssixgun

As to the coti slurry dulling an edge I don't see that,,, but the slurry "LIMITING" the sharpness ??? Yes I see that easily whether that is because of the slurry acting as a cushion that floats the very edge or the slurry bangs into the every edge is in question

Originally Posted by Steel

Out of curiosity Glen, what do YOU think is going on to LIMIT the sharpness? If not particles hitting the edge what do you theorize is going on and what led you to this theory?

Right there ..

If the particles do not break down any farther, then they would be "Floating" the very fin away from the hone
Don't know

Honestly I think it just doesn't make any sense nor does it fit my experience that an edge that is losing steel is getting "Duller" not without coming to the end of the geometry/limits of the edge and creating a failed edge what we call Over Honing



But we are also limiting the term itself to only one stone now... So does the term Slurry Dulling only apply to a Coticule ??? We know other stones can hone using slurries from start to finish also sooooooo

On that level of measurement, you don't have a "flat evenly abrasive surface" without slurry either. The whole surface of the hone is sharp abrasive particles standing proud of the substrate.

Originally Posted by gssixgun

Right there ..

If the particles do not break down any farther, then they would be "Floating" the very fin away from the hone
Don't know

Honestly I think it just doesn't make any sense nor does it fit my experience that an edge that is losing steel is getting "Duller" not without coming to the end of the geometry/limits of the edge and creating a failed edge what we call Over Honing



But we are also limiting the term itself to only one stone now... So does the term Slurry Dulling only apply to a Coticule ??? We know other stones can hone using slurries from start to finish also sooooooo

Yeah. I can appreciate your theory. I wouldn't discount it too quickly either as it may have some validity to it. In the end it is all theories and personal experiences and if we don't share them we tend to stay inside of our box. By talking about them it challenges everyone to think.

What I still don't quite understand according to the theory of the particles "floating" the edge is how would that cause a shave ready edge to degrade? In my mind, I can't dismiss that many people here (including my own experience) have reported their experience of taking a shave ready edge, raising a slurry, doing some light passes through this slurry, and noticing a marked degradation in the edge. Is there something else going on here, in your opinion? I can't see that a floating edge alone would degrade.

Could it be that both of these theories are correct to some degree? I don't know either but it sure makes you think.

Since some studies seem to indicate that the abrasive grits don't break down...only the binder. Wouldn't raising a slurry be counter productive as it would expose the "whole" boulder causing deeper scratches than the "imbedded" boulders that can only scratch as deep as their exposed height.

That explanation would seem to be born out by the experiences shared here.

Originally Posted by Splashone

On that level of measurement, you don't have a "flat evenly abrasive surface" without slurry either. The whole surface of the hone is sharp abrasive particles standing proud of the substrate.

However , if you are using a fine stone on water alone, you do not have randomly large bits rubbing on your edge.

The hazy, "kasumi" finish on Japanese knives etc is only possible due to the uneven particle sizes in the slurry but a top quality finish can be very reflective even if the different steels show contrast.

So it's a matter of degrees. It comes down to how fine the stone & how fine & thin the slurry as to what will happen at an edge.

Originally Posted by gssixgun

This is much like my pet theory>>
...I also think many more hones than just J-nats actually have a friable slurry and that the little bit that is left as you dilute out fills in between the locked in slurry again creating a smoother bevel..


But it is just a theory and a feel, not something I would say is true


But taking it back to the OP not seeing for any of that would lead to dulling though

Originally Posted by Splashone

On that level of measurement, you don't have a "flat evenly abrasive surface" without slurry either. The whole surface of the hone is sharp abrasive particles standing proud of the substrate.

https://en.wikipedia.org/wiki/Coastline_paradox

I would be very interested to hear someone who can recreate what they refer to as "slurry dulling" with a taped spine, and when it begins and is 'confirmed' to be in effect - begin stropping strokes. https://en.wikipedia.org/wiki/Angle_of_repose

A gedanken I propose: What happens to the leading edge when you drag a box across the sand at the beach?


I think in the higher the viscosity of slurry-- the net force acting towards plastic deformation by particles that beset the leading edge becomes more effective against its plebian adversary than all the net abrading force of the slurry and all the kings horses and at least 2/3 his men can reassemble with the cut.

The force on the edge doesn't have to be greater to triumph- the side of a bevel is stronger that the very edge, all that needs to happen is the ratio to increase ever so slightly to increase resistance to force of the edge- returning force on the edge, and do what you will to the sides- the edge will fall first. It's an inverse square ratio that must have balance retained for advancement to occur- otherwise the exponents will outrace any efforts. It all comes back to me as dilution. Walk through the room, now walk back with the room filled with people. Walk through a pool of water, a pool of oil, honey.. The greater the ratio of particles attempting to suspend in a solution- usually the greater the viscosity, the greater that is and the more resistance. Newtons second law...

With dilution the particles are allowed to normalize and embrace a lower viscosity and flow by fluid dynamics, whereas the drier they become (ratio of water to suspended particles falls) the more they interlock and act as larger composite rigid bodies. Please- Micro Photography of bevel advancing, and then encountering slurry dulling?

why are we ever slowing for a fine finish?- jump into the water, splash. hit the water at 60mph- -it's a brick wall. (side thought- another experiment could be a painstaking snails pace through the mud)

I would posit that stropping strokes on 'slurry dulling mud' may increase the keenness to a degree, were it to will suffer is again on the leading edge problem- instead of the bevel edge biting in harder as it advances, it will be the particles that dig deeper as they advance from far to nearer the bevels very edge- they will exit at their most embedded and on exit cause tearing- the edge while harsh, will be thinner while more obtuse. neither will likely work well. but dilution always seems to fix the problem so with the solution known-- I am unsure if this thread is debate on why diluting too late to has a counterproductive effect or what to call overdue dilution... But I know that if a slurry isn't fed water at a consistent rate while being worked, time can and eventually, inevitably will remove it, as water is lost to the stone and surrounding air, and yet we expect more water as we progress. so are we progressing and then neglecting to water and wondering why healthy plants and edges begin to wither...?

So could someone perhaps explain to me what I am maybe missing about this debate?

Aside from that- some very interesting arguments and conjectures placed. I guess a lot of people dig physics.
pass the coticule please

"Slurry Dulling" reminds me of a lot of God.

I believe it's real and I don't really care if you don't. Unless you can prove without a reasonable doubt it doesn't exist to me it does. That's my final thoughts on the topic.

Pix or it didn't happen...