Thread: A quick slurry study

Are you an ultralight touch honer or do yo do it the right way

Originally Posted by kevint

Are you an ultralight touch honer or do yo do it the right way

Dancing slurry is the way to go

Originally Posted by mainaman

Jnats slurry has flaky structure, and the break down happen by flaking off, as well as braking down....

Originally Posted by mainaman

The flatness of the grit explains the shallow scratch pattern left on the bevel.....Escher looks very similar to Jnat, the grit is flaky although to my eye not exactly the same type.....What do you guys think?

IMO, it's not only the flatness of the particles, but the fact that the particles tend to slide past each other (again, think talcum power) which further minimizes abrasion.

Originally Posted by holli4pirating

From the photos, it looks to me like the average particle size of the Jnat is the same before and after with the exception of the one big piece. It looks to me like the Escher's average size is the same before and after too, again, with the exception of one big piece.

The larger particles that you see in the Jnat slurries that are the ~same size before and after working are very likely quartz grains and not the clays. Quartz is very resistant to alteration. If you look closely, you can see that the clays are the particles that have a 'pseudo-hexagonal' shapes. Beautiful examples of this are in the raw Jnat slurry, and even in the worked slurry as well (note that you may not see perfect hexagons, but you can frequently see ~120 degree angles between particle edges).

The Escher slurry is very different and although it is almost certainly dominated by quartz, the grains are freshly broken, with fractured, angular edges as opposed to the Jnat ~hexagonal material. No evidence of this 120 degree particle shape (clay) stuff here with the Escher. The particle size you have in the slurry is the particle size you will live with/hone with.

Originally Posted by Kingfish

Given that both a these are superlative finishers, it suggests that grit size is considerably larger than many claim in the worked slurrries.i.e. 30k etc. Thanks for sharing great images. Also, it confirms my personal preference for harder stones as they release particles at a slower rate making it possible to control the particle size at the finish. Fun and useful info.

Originally Posted by thebigspendur

You need to be very careful making conclusions here. The pics are interesting but by themselves mean little. You have to know the particular chemical brakdown of the minerals making up the rock and their characteristics which will determine the result. You also have to analyze the slurry to see what you have there.

Here's an analysis of a slurry from a ~comparable Nakayama. The clays are definately there and based on the SEM data, they clearly show signs of breakdown largely by separation of layer sheets, or 'flakes'. They will all continue to physically break down in particle size with additional honing - the illite-montmorillonite (see below) moreso than the mica and chlorite.

[geek]
The components are (in relative order of abundance):

Quartz >
Illite (mica) >
Chlorite (clinochlore) >
Interstratified illite-montmorillonite (not shown) >
Albite (feldspar) >>
Goethite (trace) >>
Noncrystalline silica (not shown).

The clays include the mica, chlorite, illite, interstratified illite-montmorillonite phases. Quartz and the feldspar are silicates and they will not break down in in the slurry with honing. Goethite and noncrystalline Si are not clay minerals in the strict sense, but they are more finely-divided than any other mineral phase present, and IMO, would probably far exceed 30K grit if I had to put a number on it. What's a 30K Shapton - 0.49u in particle size? A heckuva lot of the particles you see in Stefan's pics are already on the order of <0.5u and some of this noncrystalline Si can get much smaller.
[/geek]


Anyway, I hope someone finds this useful.

those are EDS tests?

Originally Posted by mainaman

those are EDS tests?

Actually, this is x-ray diffraction (XRD). It measures mineral phase composition, essentially by analysis of crystal structures - each mineral has a unique kind of fingerprint - e.g., series of peaks and intensities - more or less. EDS gives you chemical composition. The mineral quartz, for example, is SiO2. That can be determined for a grain by EDS, but just knowing that the grain is SiO2 does not mean that it is quartz, and that's where XRD comes in...

Originally Posted by Woodash

IMO, it's not only the flatness of the particles, but the fact that the particles tend to slide past each other (again, think talcum power) which further minimizes abrasion.

The larger particles that you see in the Jnat slurries that are the ~same size before and after working are very likely quartz grains and not the clays. Quartz is very resistant to alteration. If you look closely, you can see that the clays are the particles that have a 'pseudo-hexagonal' shapes. Beautiful examples of this are in the raw Jnat slurry, and even in the worked slurry as well (note that you may not see perfect hexagons, but you can frequently see ~120 degree angles between particle edges).

The components are (in relative order of abundance):

Quartz >
Illite (mica) >
Chlorite (clinochlore) >
Interstratified illite-montmorillonite (not shown) >
Albite (feldspar) >>
Goethite (trace) >>
Noncrystalline silica (not shown).

Anyway, I hope someone finds this useful.

Two things I would like to add, firstly the mineral component of these stones are the remains of radiolaria. The finer stones would have silicates minerals as you have mentioned. How they were deposited and other non biogenic impurities minerals IMHO is what makes some of these stones finer than others. The wild card are larger non biogenic silicates mixed with the radioarian makesome of them "scratchy" and in the worst cases visible inlusions.
Another honing component does not show up but has a profound effect on how the hone is that in part,the anion component of the clays contain phosphates. These phosphate salts impart a chemical abrasion action that is no doubt weakly acidic. Phosphate salts etch steels giving them hazy look.

Originally Posted by Kingfish

Two things I would like to add, firstly the mineral component of these stones are the remains of radiolaria. The finer stones would have silicates minerals as you have mentioned. How they were deposited and other non biogenic impurities minerals IMHO is what makes some of these stones finer than others. The wild card are larger non biogenic silicates mixed with the radioarian makesome of them "scratchy" and in the worst cases visible inlusions.
Another honing component does not show up but has a profound effect on how the hone is that in part,the anion component of the clays contain phosphates. These phosphate salts impart a chemical abrasion action that is no doubt weakly acidic. Phosphate salts etch steels giving them hazy look.

The majority of the minerals/clays are the original marine sediments that were deposited and compacted during diagenesis over time. These also include, in part, the Radiolaria. A great deal of the Radiolaria have undergone dissolution and reprecipitation as amorphous (or opaline) Si that now exists as a cementing agent in the rock. As I mentioned, this noncrystalline silica is extremely finely-divided and may in part be the reason for some of the 'high-grit' response of these hones. Without further work, it's not possible to say which are the dominant components are which are (non-biogenic?) 'impurities', but suffice it to say that this amorphous Si may be considerable. Rough measurement suggests ~20-50% noncrystalline Si and 50%-80% clays, quartz, etc.

[dweeb]
Also - and I don't mean to nitpick here - any anion/phosphate adsorption on these clays is negligible - particularly in a marine environment - and even if there was enough phosphate to be retained by the clays, it's only a surface phenomenon and not anything that would change the physical characteristics of the clay sufficiently to cause a 'honing effect'. E.g., there is no discrete 'phosphate salt' mineral phase present in these materials. If you'd like to discuss further, feel free to pm me.
[/dweeb]

Stefan
Really fine posting. I have read that the type of quartz in the Tamba Terrane-Kyoto area geology is a form of chert. On the west coast here in California and Oregon besides obsidion, chert was a favorite rock used by the indigenous tribes for spear heads and other points. Chert is favored in this application for its flacking characteristics in developing the sharp edges, and I was wondering if this knack for flacking continues down to the microscopic level also.

I was also hoping that at some point someone would do the same photographic study side by side as you have done with a fine Nakayama and a Shapton 30k to help put this all into perspective. If Norton or another company has a 20k or 30k for reference fine, it is just that Shapton is the finest that I have heard of.

I have been going back and forth with a few other shapeners, and the issue of charting the grit particle size is based on what. The largest of the avaliable particles or the average size amongst the particles or is it the smallest particle. Whats your take on this. Alx

P.S. I would be happy to provide sample grit from my stock.

Alex,
thanks I can do Shapton 30k if you can send me grit from it.
I'll pm you

Originally Posted by alx

On the west coast here in California and Oregon besides obsidion, chert was a favorite rock used by the indigenous tribes for spear heads and other points. Chert is favored in this application for its flacking characteristics in developing the sharp edges, and I was wondering if this knack for flacking continues down to the microscopic level also.

This is similar to the Escher particles above.