Thread: BUBBLING GOTICULE

Originally Posted by Smokintbird

Sham - I am interested in this neat bubbling problem you have.....

Could you try soaking the stone for an hour?

I think that would rule out the idea of the stone's porosity being the culprit if it still bubbles...


How about stopping by the grocery store and getting some distilled water?

This would rule out the idea of chemical reaction between something in the water and the stone.....


If both tests still bubble equally, then I would say that your stone must have air pockets in the matrix of the binder and it is simply being released as you hone...

I go do this. lets see what happens. by the way i like the ideas.

Just to make sure it's not some crazy chemical reaction or embedded soap:

-whip up some slurry from a "normal coticule" and some distilled water
-do the same with your bubbling stone


do a comparative test with some pH strips and see what happens.

It's not some gas or air escaping from the stone. If that were the case, then it would do it without honing. The stone is not porous, but it's not perfectly flat either; there are irregularities in the surface. As you move the blade across the stone, a small amount of air gets trapped between the blade and stone. Normally, this air gets released as the blade passes. However, do to the elasticity of the slurry on this particular stone, the air gets trapped in in the slurry and forms bubbles. So, the question is what is causing the elasticity; is it residual soap from a previous user, or some other substance embedded within the stone causing the phenomenon?

BTW, considering the performance of this particular stone, it ain't broke, so don't fix it.

Originally Posted by radaddict

It's not some gas or air escaping from the stone. If that were the case, then it would do it without honing. The stone is not porous, but it's not perfectly flat either; there are irregularities in the surface. As you move the blade across the stone, a small amount of air gets trapped between the blade and stone. Normally, this air gets released as the blade passes. However, do to the elasticity of the slurry on this particular stone, the air gets trapped in in the slurry and forms bubbles. So, the question is what is causing the elasticity; is it residual soap from a previous user, or some other substance embedded within the stone causing the phenomenon?

BTW, considering the performance of this particular stone, it ain't broke, so don't fix it.

Based on the info given so far, this seems the clearest and most likely explanation.

Originally Posted by radaddict

It's not some gas or air escaping from the stone. If that were the case, then it would do it without honing. The stone is not porous, but it's not perfectly flat either; there are irregularities in the surface. As you move the blade across the stone, a small amount of air gets trapped between the blade and stone. Normally, this air gets released as the blade passes. However, do to the elasticity of the slurry on this particular stone, the air gets trapped in in the slurry and forms bubbles. So, the question is what is causing the elasticity; is it residual soap from a previous user, or some other substance embedded within the stone causing the phenomenon?

BTW, considering the performance of this particular stone, it ain't broke, so don't fix it.

I buy this explanation too. I still am in the camp that there may be some oil or soap in the mix somehow too though, because I simply can't think of a mineral that would make an elastic slurry, or even something that would increase the surface tension of water (let me remind you most things decrease surface tension...)

Originally Posted by khaos

I buy this explanation too. I still am in the camp that there may be some oil or soap in the mix somehow too though, because I simply can't think of a mineral that would make an elastic slurry, or even something that would increase the surface tension of water (let me remind you most things decrease surface tension...)

Well, who knows what was going on when this stone was forming. There could be trace amounts of organic material that, with water added, mimics the characteristics of soap. I think some salts have detergent properties as well. As for the surface tension, soap decreases surface tension. I think bubbles will form more easily when the water's surface tension is decreased. Of course, without a detailed analysis of this particular stone, we can speculate until the cows come home and never have a definitive answer.

It would be nice to know what is causing the bubbles and if that is what gives this stone it's outstanding polishing properties. If it is some salt or organic material, perhaps we could sprinkle it on other coticules (like fairy dust) to enhance the stones performance as a hone.

Originally Posted by radaddict

Well, who knows what was going on when this stone was forming. There could be trace amounts of organic material that, with water added, mimics the characteristics of soap. I think some salts have detergent properties as well. As for the surface tension, soap decreases surface tension. I think bubbles will form more easily when the water's surface tension is decreased. Of course, without a detailed analysis of this particular stone, we can speculate until the cows come home and never have a definitive answer.

It would be nice to know what is causing the bubbles and if that is what gives this stone it's outstanding polishing properties. If it is some salt or organic material, perhaps we could sprinkle it on other coticules (like fairy dust) to enhance the stones performance as a hone.

Nope, its a metamorphic rock subjected to heat and pressure. No organic material would survive it without being changed into graphite or some xtlized form of carbon.

Originally Posted by thebigspendur

Nope, its a metamorphic rock subjected to heat and pressure. No organic material would survive it without being changed into graphite or some xtlized form of carbon.

Ah well, it was mere speculation after all. So then, a metamorphic rock with perhaps metaphysic properties. The mythical hone of plenty!

There is an interesting article here about coticule formation and the elements in the sedimentary layers before they were transformed by pressure/stress/temperature into metamorphic layers.

The coticule in question (if indeed it is one - it certainly looks like one) would not be porous, except superficially at the surface and sides. It has been lapped, so any surface contamination should have been removed.

Three things that remain are (1) it isn't a coticule, (2) there is still contamination of some sort along the sides, (3) the water being used during honing.

I think I would try to rule out (2) and (3), for the former by lapping the sides and for the latter by using distilled or deionised water. Once those two have been taken out of the equation, only the rock is left. If the lapping has been thorough enough to rule out any user-induced contamination, then the bubbles must be caused by an inherent quality of the stone itself.

I don't know anything about specifics of how these stones were quarried, but I would like to know what layers would be found both above and below the coticule layers, and whether anything of the make up of these layers could be incorporated into the stone, in other words whether it came from upper or lower boundaries and contained something of another layer.

I have a BBW that has spots of yellow in it and which is a very fast cutting stone. BBW and yellow coticule hones come from the same area, so these two must be found in adjacent layers, and posibly my BBW was taken from the layer which shared a boundary with the yellow coticule layer, and incorporates part of that layer within itself. Perhaps some other contiguous layers have added something to this foaming coticule?

Not being a chemist or geologist doesn't help, but I have seen the word "montmorillonitic" mentioned in connection with the upper layers of coticule strata, and that some forms of this material are called saponite, or "soap-stone" - but whether this is found in the Ardennes I don't know, or even if it is found in close proximity to metamorphic rocks like coticule.

Regards,
Neil.