Thread: Slurry Dulling

As far as I know, it was a term used (first?) and frequently on coti.be, specifically for coticules. There is nothing more fun than covering a coti with a mud slurry and proceeding to do countless laps. Unfortunately it doesn't really sharpen your razor. The simple, but non technical explanation over there, was that the rate of steel removal was higher than the rate of polishing therefore the edge of the bevel is never allowed to reach its minimum effective width.

I know that you guys are all being humble and what not, and know much more about it than me, but the fact that one needs to dilute slurry on certain stones validates the idea that dulling exists, and whether you agree with it or not, if you do dilute by default you agree.

If we turned to the Escher though, I would be more at a loss. I really can't tell the difference (by shave) of whether slurry (with or without dilution) was used. (I've only had a couple of Eschers though. Maybe it matters more on some than others.)

Isn't this the moment when a member with an electron microscope steps in?

And shows that jnat slorry does not break down? And more than 5 passes on the strop does nothing?

Runs and ducks!

Originally Posted by andrewmurray86

One thing I've noticed is that if you reply to this thread the Glen will thank you. What a generous soul.

Seriously though, I've nothing to add to this post but it's interesting to follow and read.

Everyone but me... I don't think Glenn believes me about this particular stone and is on a rampant search for one as we speak...

Originally Posted by AndreGrobler

And shows that jnat slorry does not break down? And more than 5 passes on the strop does nothing?

Runs and ducks!

There is no way to show that the slurry of a J-Nat does not break down unless one can measure the thickness of the slurry platelets. That is not possible.

Originally Posted by mainaman

There is no way to show that the slurry of a J-Nat does not break down unless one can measure the thickness of the slurry platelets. That is not possible.

https://scienceofsharp.wordpress.com...ry-break-down/

I honestly wouldnt know... this serms to indicate otherwise... it cannot be called exhaustive however...

P.s. the post does show that the binding agent or clay particles do break down, but that the sillicates do not... so the possibility exists that the way the slurry abrades might be changed due to the softer non abrasive particles...

Which in this greatly nuanced world of sharpening... m8ght be a big deal...

Originally Posted by AndreGrobler

https://scienceofsharp.wordpress.com...ry-break-down/

I honestly wouldnt know... this serms to indicate otherwise... it cannot be called exhaustive however...

No it does not. The experiment is not defined clearly and the results are not all inclusive. The guy did not measure the thickness of the slurry plates.
The only way one can prove whether the slurry breaks or doesn't is to measure the thickness of the slurry particles and do statistical analysis, that measurement is impossible with an SEM.

What do you mean by slurry particles?

Originally Posted by Frankenstein

As far as I know, it was a term used (first?) and frequently on coti.be, specifically for coticules. There is nothing more fun than covering a coti with a mud slurry and proceeding to do countless laps. Unfortunately it doesn't really sharpen your razor. The simple, but non technical explanation over there, was that the rate of steel removal was higher than the rate of polishing therefore the edge of the bevel is never allowed to reach its minimum effective width.

I know that you guys are all being humble and what not, and know much more about it than me, but the fact that one needs to dilute slurry on certain stones validates the idea that dulling exists, and whether you agree with it or not, if you do dilute by default you agree.

Good discussion here.

I think there is something about this above statement. Assuming that the slurry don't change its properties while honing, and that slurry consistency is the only variable I think this is quite a good description. For a given slurry there is a finite sharpness to be achieved (which will/could be different for different honers, stones and steels). If the razor is duller than this sharpness, it will be refined until it won't get sharper on this slurry consistency. If it is sharp to begin with, slurry dulling will take it down to the sharpness dictated by that very slurry. For me, this is apply to honing on a coti.

If, however, the slurry changes as it gets worked (breakdown, slurry particle rounding, whatever) the slurry may allow for more edge refinement and a sharper edge by working it longer. Without entering the existence or non-existence of the breakdown, this is what I experience on some jnat slurries. The honing feedback often gets smoother and the bevel polish/haze becomes finer and finer while keeping the consistency constant (not diluting). Still, there is a balance act between consistency and slurry refinement, and at any point in time the slurry consistency is either too thick vs fineness (dulling effect), just right (edge gets sharper) or too thin (edge gets sharper, but at a slower rate).

Going through a nagura progression, to me it seems like for each new step, the edge is taken back a tad, and then gets refined to a sharper state than on the previous slurry.

Of course, this leaves the question open about what really happens at the edge and on/under the bevel while honing. On the other hand, as long as the blade feels good on the stone, the shaves are nice and I'm having a good time honing it doesn't really matter

keep the slurry talk coming!

Sedell