Thread: Switching Slurries on Coti's/BBW's

Originally Posted by JimmyHAD

Bart said that the garnets in the blue are larger than the garnets in the yellow IIRC. I also recall someone (not sure who) posting that they used a yellow slurry stone on a blue because they only had the yellow/slate slurry stone. I don't know that it hurt or helped.

I do recall mparker posting that a nagura is not a slurry stone and that it wouldn't be a good idea to use it as one. With stones that I don't have a slurry stone for I use a DMT 3" 325 credit card sized continuous plate. Works well for me.

That's a good idea, those small DMT's. Larger Garnet's in the blue make sense, if you think about it. I mean, it works, I got great edges by doing that. The thing is, I seldomly stop at a coticule, I'll go on to a Shapton, or Nakayama, sometimes, I'll stop at the Naniwa, also a great finisher....

Naguras are pretty much sold exclusively as slurry stones.

You know when your talking hones with garnets there are many factors to consider. There's the type of garnet, the type of xtl, the size of the xtl and how readily the stone comprising the hone gives up the garnets.

nagura is an upper middle stone. Both a harder and softer one are used by nihonto togi -a very good one of sword polishing size is worth thousand(s) of dollars.

A block of chalk rubbed on a hard, fine razor finish hone is unlikely to help with what we want to do. the same or similar stone or diamond does

interesting idea mixing slurries, I have not tried it. Although, it might just be a stroke saving excersise if you end up doing strokes with just water.

On the stones I do not have a slurry stone for, I use a small sanding block - seems to do the job.

Actually, I have horsed around with this a little bit.

I think using a belgian blue slurry on a coti makes it a bit slower and "softer",

And using a coticule slurry on a blue speeds it up a bit.

I think there's more to the BBW's than the garnets really.

Here's a quote from Rob at Ardennes Coticule:
"Coticule stones have always more garnets than a BBW stone and the garnets of a Coticule are always smaller than those of the BBW.
Smaller garnets <-> more garnets --> higher grit
Larger garnets <-> less garnets --> lower grit"

When I bought my first natural coticule from Howard, I also bought a slurry stone. The slurry stone is coticule, with a slate backing.

When I use the coticule slurry stone on the coticule side, I get milky white coticule slurry. When I use the same coticule slurry stone on the blue side, I get blue (purple?) slurry. Can't explain this, but it's what I see. And the blue slurry definitely feels and cuts different, even when raised by the coticule.

I've never tried building a coticule slurry on the coticule side, and then transferring it to the blue side. I like what each type of slurry does when matched to it's side. But I have tried dripping coticule slurry onto a DMT8000, without any effect I could see. The DMT felt a little different, but didn't really cut any more "gently". Diamonds are just harder than garnets, maybe?