Thread: Charnley slurry dulls edge?

as the new owner of a DMT 325 wallet card, i'm now able to truly raise a productive slury on my CF. Does anyone know if the slurry on a CF (or on all none-jnat) dulls an edge?

I think any slurry can have the tendency to dull slightly depending on the thickness of the mix. The concept being to release abrasive to increase the cutting power so you have all that garnet or quartz bumping into the very edge as well as going under it. Then the slow dilution decreases the amount and lessens the tendency. In talking about the Charnley with Lynn he said he had better results with light oil and no slurry and I think hi_bud_gl said the same thing. Experiment with a few and see what works best is all we can do.

I guess it depends a good bit on what you are trying to do. I just finished doing some edge repair on one of these brown/tan (I assume) British novoculites, which are a very hard and fast stone.

The blade was shaving but I wanted to even it out. I raised a light slurry on the hone and quickly (maybe 100 regular strokes) put a flat edge on the razor. No dilution. It was also felling arm hair silently at the very ends of the hair.

So, my point is, the slurry dulled the razor from shave ready, but still had it almost ready for finishing (the examples of this type of stone I have used leave a rough edge with slurry that has to be further smoothed out, heavy slurry can cause chipping).

The sharpness on this stone with water (I use soap) is much greater than with slurry.

Not a direct answer to your question about the Charnley Forrest, but a little info about another non-japanese natural hone.

regards,
Torolf

As I understand it, the charnley forest is similar to the Arkansas, in that the abrasive particles are very very hard novaculite. If that is the case, when you use slurry made by the 325 grit diamond card, you are essentially making a mixture of tons of big, hard particles. So yeah, I can see a serious dulling effect, with a thick slurry. Thinner slurries, used similarly to coti slurry, might hone...but you won't be finishing.

Then I've probably just dulled two razors. I know that the slurry was thicker than usual. i had been using a CF slurry stone to raise a thin slurry so that there would be some feedback instead of that slippery silence. But i surely went too far with that diamond card.

But now that the blades are dull it seems that I've got to drop back to the Belgium Blue and start sharpening again.

Do you need to use a slurry to finish on a Charnley? At that stage, I'd be using just oil.

(I don't have a CF, but they are indeed Oil Stones...)

Thanks Disburden

I don't see the need for slurry on a CF at all. From what I've been told oil is the way to go when trying to get the best possible edge from the stone.

I've been finishing on a CF for about a year now and have tried both water w/soap and oil. "Slurry" has NOT worked for me. At first I was using 3n1 oil and it was too thick & my blades were literally hydroplaning over the stone. I was scratching my head for a while on this one until I talked to the guru. I talked to Lynn and he recommended sewing machine oil, so I ordered some up. I start with about three drops on the stone (my CF is roughly 10.25" x 2.25") and uniformly coat the surface via fingertip. I then start with 10 circles each direction on each side...only enough pressure to keep the blade on the stone & my movements are slow compared to working on water stones to avoid the "hydroplaning". I wipe the blade well and do 10 "x" strokes each side, wiping the blade after each complete 10x's. I do this 8 times for a total of 100 strokes (10 circles one way, 10 circles the other way, 80 x's) on the CF an it works EVERY time for me. The CF is a slow stone on oil, but leaves a magnificantly smooth shaving edge every time if you have done your work on the other stones right.

I would not use slurry on CF for finishing. Yes it speeded up the process but realy doez not go all the way to the end. You can start with it but need to finish on clean water or oil.

using slurry should also, by my understanding, refresh an otherwise fine broken in surface, diminishing the surfaces abilities as a final finisher.
ever one i've heard from on the subject says that after breaking in the surface it becomes finer and smoother like other arkansas hones (both being novaculite).
not that a fresh lapped CF surface isn't still fine, mind you.