Thread: Stupid Question...????

I will preface this by saying i have NOT and do NOT plan to do this but have been wondering....

could you use the slate side of a coticule? i have seen other slate be used what make one slate better than another?


thanks

That really depends on what material the slate is. Some coticules have BBW for slate - Belgian Blue Whetstone, which is a nice stone in itself. This is a useable middle grit stone that is used before the yellow side of the stone. Other coticules do not have this BBW but just some other backing that is not suited for honing.

Do a search for BBW, there are many threads on it. See for instance this thread, and maybe post some pics with slurry to help get a proper ID of your stone.

Best of luck.

i know the one i have does NOT have a BBW side and i guess i am wondering what makes one slate suitable for honing and one not.....are the non-suitable slates to brittle?

For a slate to work as hone it needs to have hard enough abrasive particles, the more the better and they need to be relatively uniform in size. I have plenty of Coticules but none backed by slate used by Ardennes so I haven't been able to test them.

The slate that is used to support coticules can be used for honing. From their nature they do have fine sized abrasive particles. But, since they are not meant to be used as hones, they might have inclusions that can easily damage your razor. You can test it on a cheap knife, and if you find it suitable for honing, use both sides.

From the Ardennes website:

" Both the rectangled and the odd shaped (= bout) whetstone consist of a Coticule top side of 7 to 10 mm and a bottom side of unusable black shist. "

it depends.
i use my back of coticule and the result is better. i think the back side is an escher.

Rob from Ardennes Coticule has categorically stated that they use Portuguese or Brazilian black schist for the backing, and that it is not suitable for honing - he should know! When the mine was owned by others (a long time ago), either BBW or blue schist (the same as BBW but with far less - if any - garnet content) was used. The schist that formed next to the coticule layer was rich in garnet and can be used for honing - the type with little yellow or pink spots in it is best. Natural dual layer hones are of this type. The further away from the coticule layer you go, the less the garnet content - some layers are devoid of garnet and so cannot be called BBW. Older coticules are backed either with a slab of BBW glued to them or the blue schist, so some backings that are blue to purple may be useful for honing on and some not. If the coticule is modern and if the backing is grey it is not suitable for honing on.

One interesting BBW layer is very rich in garnet and almost as fine as a very soft coticule in honing performance, but it is found between two layers of ordinary blue schist and never against a layer of yellow coticule. Evidently, the climatic events at the time that deposited a coticule layer and then covered it with a slower forming mudstone layer that had a rich garnet content did not produce the right elements for coticule formation.

Slates and schists are subtly different - slate is an 'in between' stage so the constituents are much the same, but schist has undergone more metamorphic change than slate. Incidentally, schist itself is an 'in between' stage - the most metamorphosed type is known as gneiss, so slate in metamorphic terms is low grade, schist is medium and gneiss is high. All begin with the same material - shale. For slate/schist to be usable as a hone it must have an abrasive content like garnet or quartz for example, or some other siliceous matter - not all slates/schists have this, and some have inclusions that are far harder than the matrix that cause scratches.

Regards,
Neil

Originally Posted by linguist

it depends.
i use my back of coticule and the result is better. i think the back side is an escher.

Ha - the back of mine is a Jnat