Thread: The other side of the coti

Buying vintage glued combos is the way to go. Even if the coti is bottomed out, you have a good shot at the backing being salm.

Originally Posted by kcb5150

Buying vintage glued combos is the way to go.

Absolutely. Especially the deep rock variant. Kosher, too.

Not.

I'm talking about if you want good bbw, not a coti in general...

As far as cotis go, new or old doesn't really have any quality impact, new can actually be better in the sense that you can specify what you are looking for vs taking a punt on something costly because it has a box or stamps. But if you want a nice slab of bbw, I maintain my opinion on the old stuff having a better chance for a more interesting specimen.

Found a pic of the rock I was talking about. This is the best bit of bbw I have.

This is my next best bit, and weirdly, if you were just to judge it in person going by appearances, it wouldn't be promising.

I too did my own BBW study, several years ago during my Coticule collecting period that was rampant then.

And I also conclude that, it depends on the stone, like all naturals. Some perform, some don’t. I really don’t use Coticules much anymore, for me there are better alternatives and the only good thing to come out of it for me was the discovery of the “French Stones” Vosegine/ La Loraine, which I still actively collect, and there too they vary wildly in performance.

There is tons of info, test and techniques on the BBW on this and other fora. Try it, experiment with all the techniques and see if it works for you. Some can bevel set and some can finish.

In the older times blue belgian whetstone was not sold as a sole whetstone. But LaLorraine, the reddish blue stone, which is a separate layer in the coticule quarries, was typically sold. This LaLorraine layer shows significantly better sharpening performance than the normal quality BBW stones.



The interesting thing is, that old investigations of Grognard (Grognard: Le Roche Salmines A coticule dans la region de Salmchateau) showed only a small amount of garnets (grenats/ spessartine) in Lorraine stones. The garnet size was measured as high as in the Blue whetstone (Phyllade).
So following garnet concentrations and sizes are typical for the different Belgian whetstones, according to Grognards investigations:

Coticule: 35-45 % garnets 10-20µm
BBW: 20-25% garnets 15-30 µm
LaLorraine: 5% garnets 30µm

The interesting thing concerning the LaLorraine is following. First - there is a significant amount of quartz in the stone, quartz particles that were visible through a microscope.
The quartz in coticules normally is seen as a poison. The abrasive performance is done by the garnets. But in the LaLorraine stone the included quartz could be an abrasive too.
Second is, that the Lorraine stones contain a lot of Ironoxide. Iron oxide in form of red Fe2O3 is a good polishing substance. It is a very fine polisher, you may know the red polishing paste which mainly consist of red ironoxide.
So these two specialties in the La Lorraine stones may be responsible for the good honing performance of these stones.

Another interesting issue that Grognard found concerning BBW backed to coticule is, that there is a correlation of the garnet content of BBW to the quality of the accompanying coticule.
In natural combination coticules, where the quality of the coticule layer was regarded only as medium, the garnet content of the BBW on the backside was as low as 5%.
On the other hand he found in most of the high quality coticules a garnet amount of up to 25% in BBW side.

Originally Posted by TristanLudlow

I love the BBW, the diversity in appearance is very interesting and highly appealing to my eyes.

I've got around 20 or so and they are mostly different looking, a couple ones are from the same vein, and most of mine are natural combo stones; very nice looking stones, I dig their appearance more than the coticules or anything else for that matter.

I also got one from ardennes coticule a while ago, it's a very big hone and has been a main workhorse and it took a permanent spot in my honing routine.

I use mine mostly on slurry to reach maximum keenness, after the coti with slurry and before the coti with just water.
Works very well, it's become part of my routine and gets me excellent results.
It's basically this method: http://www.coticule.be/progressive-honing-method.html




Hirlau, how do you like to use yours? Just water or with slurry?

I use my purple side( that color seems to match mine after it is wet & slurried) I wouldn't call it blue.
I use it after the 4K Norton ,,, slurried first,,, then water only,,,, jump to the yellow side to a very light slurry,,,,, then finish the razor with the yellow side, water only,,,,, then strop.

I tried it, and it worked, but to be honest, except for the experiment I didn't see the point as it is slower working than the regular coticule side of the hone. I would rather buy a cheap small coticule than a larger BBW to work with. Also, if I remember the study well, one test person did feel the difference in edge obtained.

Well OP you are right. No one raves about honing on a Belgian Blue because they aren't phenomenal. They do work but ever so slowly. I've had a good bb before but on my combo coticule the bb side is slow as hell. I only use it if I feel like it. The coticule is much more effective as a hone. My 2 cents.. and if we're talking Canadian currency.. that's - 25 cents