Thread: A quick slurry study

Well, yeah, but you don't say what makes you think that? I mean to me it seems rather useless to post a bunch of computer generated images along with unsubstantiated claims and just leave it at that.
That's certainly not a 'study' and you probably know that. I was hoping we can learn something from this, but that would involve proper identification of what is what on these images.
With the information available so far, any conclusion different from 'meaningless' is wrong.

Originally Posted by gugi

I'm thinking three things about these photographs and the speculations about them:
(1) where is the evidence of 'flaking'
(2) where is the evidence of 'break down'
(3) what is the definition of 'grit size' for a mixture of particles of different size

There are many reasons for the contrast in a SEM image, the challenge isn't taking pretty pictures, it's figuring out their meaning.
I'm still at loss at what these images mean, by themselves they can be interpreted in completely different ways, so at this point they're completely meaningless.

Personally, I don't think this stuff is useless at all. In the Jnats, I see a clear indication of particle size reduction (your point #2 - 'breakdown') going from the raw slurry to the worked slurry. That alone is worth the price of admission alone, IMO. It's a small sample so who knows - but the trend is there.

There is also more than casual evidence that the majority of these particles that are breaking down are specifically clays, based on the pseudohexagonal particle morphology and known mineralogy that I posted above. We know that clays are some of the few minerals that can breakdown under mechanical abrasion, and that that effect is one of the main features that distinguish the behavior of Jnats from coticles (with e.g., garnets). In fairness, although we see more 'fines' in the worked slurry, we cannot determine from the SEM images alone whether these fines originated from 'flaking' (#1) of the clays (peeling away of layers) or from mechanical abrasion.

The Jnat quartz grains look to me to be relatively unaltered (same size)between raw and worked pics.

On the other side of the coin, the Escher particles are quite different and are dominated by fractured quartz grains that appear to have relatively little alteration from raw to worked slurry.

Originally Posted by gugi

Well, yeah, but you don't say what makes you think that? I mean to me it seems rather useless to post a bunch of computer generated images along with unsubstantiated claims and just leave it at that.

That's certainly not a 'study' and you probably know that. I was hoping we can learn something from this, but that would involve proper identification of what is what on these images.

With the information available so far, any conclusion different from 'meaningless' is wrong.

I think there is more information here than might initially meet the eye. Here, we have some SEM and XRD data that - at lease in part - explains the 'Jnat effect', what components are at play, and how they all differ from the behavior of, say, a coticle.

Originally Posted by gugi

Well, yeah, but you don't say what makes you think that? I mean to me it seems rather useless to post a bunch of computer generated images along with unsubstantiated claims and just leave it at that.
That's certainly not a 'study' and you probably know that. I was hoping we can learn something from this, but that would involve proper identification of what is what on these images.
With the information available so far, any conclusion different from 'meaningless' is wrong.

I wanted to study how the grit looks like, I guess this is not it so sorry for the wrong title.

I should have clearly started with the disclaimer that this is my own point of view and everyone should feel very free to completely ignore what I was sharing with the forum.

Originally Posted by Woodash

Personally, I don't think this stuff is useless at all. In the Jnats, I see a clear indication of particle size reduction (your point #2 - 'breakdown') going from the raw slurry to the worked slurry. That alone is worth the price of admission alone, IMO. It's a small sample so who knows - but the trend is there.

Let's focus in on this one. I don't see a reduction in the particle size and Gugi also disagrees, so clearly there is no clear indication of particle size reduction. Then Stefan said it's about the thickness not just the size, and I don't have any idea how one can tell thickness from these pictures. Not to mention breakdown of slurry is a statistical effect, and those tiny samples are nowhere enough data to point out any kind of "trend." Heck, the average particle size, thickness, or mass could even be a result of how the samples are taken, but with no thorough documentation of a procedure, we would never know. As Gugi said, you need someone who is skilled in interpreting these photos - I know I'm certainly not and I don't know who is.

Then there is the point TBS raised - the diamond plate itself will affect the initial, and therefore the final, shape of the slurry. That is another factor that needs to be considered as well.

This is not razor work anymore, it is LAB work. It requires a very scientific approach on all fronts, from the procedure to the samples to the "data" to the interpretation. I don't see any of that. All I see is some pretty pictures.

I see no reduction in particle size... I see a bunch of people drawing broad conclusions from one photo of each sample, and blindly engaging in the fallacy that if someone uses fancy equipment and can cut-and-paste spectrograph charts it must be scientific and is imminently practical.


Baloney.

Originally Posted by holli4pirating

Let's focus in on this one. I don't see a reduction in the particle size and Gugi also disagrees, so clearly there is no clear indication of particle size reduction. Then Stefan said it's about the thickness not just the size, and I don't have any idea how one can tell thickness from these pictures. Not to mention breakdown of slurry is a statistical effect, and those tiny samples are nowhere enough data to point out any kind of "trend." Heck, the average particle size, thickness, or mass could even be a result of how the samples are taken, but with no thorough documentation of a procedure, we would never know. As Gugi said, you need someone who is skilled in interpreting these photos - I know I'm certainly not and I don't know who is.

Then there is the point TBS raised - the diamond plate itself will affect the initial, and therefore the final, shape of the slurry. That is another factor that needs to be considered as well.

This is not razor work anymore, it is LAB work. It requires a very scientific approach on all fronts, from the procedure to the samples to the "data" to the interpretation. I don't see any of that. All I see is some pretty pictures.

That's my point (above) - you can't. But there are, to me a lot more fines in the worked slurry. Well, a 'trend' can be based on whatever you or I deem reasonable. I do agree with you completely that this is a very small sample and all we can do is interpret the trends that we each see.

The trend that I see are many particles in the worked slurry of <0.5u and many on the order of ~0.1u or less that surface alteration features that are not present in the raw slurry (fewer pseudohexagonal platelets, for one). This trend does not include quartz.

I'll just say that the trends that I interpret are based on a lot of previous experience that I have with this type of stuff. Doesn't make me right, but I believe I can point out a couple of things that might not occur to a lot of folks.

The 'skilled' way to interpret particle size is to sample it appropriately, and to then do a digital image analysis to particle size/shape, etc. There are many possibilities here, but hey - I look at this simply as a fun excersise that may be of interest to some people. No more, no less. Is it going to be published by the National Academy of Sciences - no. But I maintain that there is still interesting and useful information here.

Lastly, I didn't catch all the details on the diamond plate situation. I assume it was used to raise a slurry off the Jnat which was then sampled for SEM. The same slurry was then worked on the hone and then sampled for the second SEM image. Same plate used to create a slurry with the only difference being the razor working. There is no evidence of loose diamond in the slurry or anything. I'm not sure what you getting at - can you please clarify?

Anyway - I'm going on too much with all this. Happy to continue the discussion here or via PM anytime, though.

Originally Posted by Woodash

That's my point (above) - you can't. But there are, to me a lot more fines in the worked slurry. Well, a 'trend' can be based on whatever you or I deem reasonable.

Anyway - I'm going on too much with all this. Happy to continue the discussion here or via PM anytime, though.

There would be no point; we've been having entirely different discussions all along, as indicated by the first few sentences in your post.

Originally Posted by mainaman

Tom,

I just put the grit on a glass slide to see how it looks like.
A very thorough research will reveal a lot of interesting data, but it takes time, preparation and money. I basically smuggled my grit samples with my research samples, and took some quick pics.Private use of the SEM is in the range $160/hour so this out of question for me.
I'd imagine this study with more detail would be interesting topic for a geologist. For me the results are satisfying and explain how the grit works, I would be happy to hear further results on the subject if a person knowledgeable in rocks would be able to research more.

You know Stephan, I for one am very satisfied that you made these images available. It is a study where we can use our imaginations connected to what is normaly unseen. Some get more out of studying than others, you don't have to change the title at all.
i.e. You can have a sample size where clear differences in size and shape are quantified and standardized by scale. Anyone who needs more than that to get new ideas and rethink old ones probably needs to start a committee and go through proper chanels anyway.

Hello Stefan


I wanted to pass on a couple of thoughts here. I do not know if you ever sharpen tools or not, but if you do you realize that the hand pressure required in honing tools is much greater than for honing a razor. Therefore the compression factor should be relatively greater for tools. The theory that the grit breaks down into smaller particles during sharpening has been touted for years in the circles of tool sharpeners and if not for centuries in Japan, and only picked up fairly recently hereabouts by razor sharpeners.


Mosts regular users of natural Japanese stones do not doubt that the grit becomes smaller through friction, but how small was always the unknown. I would think that you have already read or heard of the phenomenon in both natural sharpening stones as well as synthetic stones where two or more grit particles remain bonded together during the sharpening process and act as a larger single grit abrasive. If you think of a 10 micron size grit particle bonded with another 10 particle the resulting scratch will be larger than if a single 10 if it was acting alone.


I mention this because when I look at the freely floating Jnatural grit in your photos, and the bonded-in a string or rope form, of the Shapton/on Glass grit under the SEM microscope, I begin to wonder about the possibility of the Shapton 30k grit acting as a super particle. In my crude photo studies with the Shapton 30k these past couple of years I was always surprised at how course the scratches appeared as the blade came off of a freshly lapped Shapton 30k stone. In fact the scratches from the 30k Shapton were not that much smaller than those of the 15k scratches. All of my photos of scratch patterns on the blades were taken after a trial of 20 to 40 strokes were done on the stone being tested, from stone to stone to stone.


The Shapton30k was always an aggressive cutter in those first 40 strokes and the scratches on the steel looked bolder and bigger than what I thought a 30k scratch should look. I did a couple of tests where I stroked the blade up to 1000 times on the Shapton as well as another study with 1000 strokes on a Ohira stone. The scratch pattern on the Ohira never changed, but the scratch pattern on the Shapton almost disappeared after 300 strokes leaving a bright shiny surface, like a mirror. During these tests I did not lap the stones over and over again during the sharpening of 1000 strokes, I just continued on with it as it sat and only adding water when needed, the same proceedure I followed with the Ohira stone.


As you may know and is reported, the Shapton/on Glass 30k becomes loaded with swarf after about 4 repeated strokes on any given spot on the stone, and within a very few minutes the whole stone becomes black and slick with lots of suction. To struggle with the 1000 strokes, a 45 minute process, I had to add water every few moments and it was a real challenge. My conclusions to this sharpening session were that the Shapton did cut the steel of the bevel in the first 100 strokes or so, and produced a very distinct scratch pattern. But after the stone filled up with swarf the stone began to act as a burnishing tool rather than a cutting abrasive tool and thereby leaving the steel very shiny but not necessarily sharper.


I believe that I can now see that although the Shapton/on Glass 30k stone does have 30k grit, there is a chance that the proprietary bonding formula that the Shapton company uses may hamper the easy release of these grit particles to act as free agents in 30k size, and that because of that lack of release the 30k particles may be leaving larger scratches than a 30k should look like.


Here again I will bring up the point about the type of quartz. According to this study found at http://www.gsj.jp/Pub/Bull_new/vol_5...1/53_01_05.pdf the type of quartz in the Kyoto Honyama stones is referred to as Chert, a known mineral that does flake through friction. This flacking quality if it does in fact occur at the microscopic level, should be accelerated by additional downward force as well as by general back and forth shifting of the particles.


With the light hand in honing as prescribed often in this and other forums on razor sharpening, the flacking of the chert should be less dramatic than with the heavy hand of a person sharpening a chisel or plane blade. This may help explain the lack numerous smaller flakes in the worked slurry photos. Thank you again for your insightful photos.

Well, how to put this. If I were in charge of the introductory physics you guys have taken, you'd have barely passed.

Here are three very serious problems with your conjectures:

(1) You have to first demonstrate that the contrast on that image is produced by 'particles' (meaning particle boundaries). First thing you have to remember is that this image is a result of electrons interacting with whatever is there, so you should treat it the same way you treat that X-ray diagram, i.e. there is data in there, but the meaning of that data needs to be extracted. To claim that those white blurbs on the black background are slurry particles is rather naive. There are at least three more images necessary to establish this correlation.

(2) Suppose you've established that the contrast is from the slurry particles. There is a wide range of sizes, therefore first you have to establish that the two images show in fact different distributions of sizes (your brain is terrible at analyzing this type of information, which you should know from the <---> and >---< trick you saw as a kid). Since you posted X-ray peaks, you shouldn't have a problem with looking at the spectral analysis of the SEM images (fourier, wavelet, etc.) to determine if there are actual differences in the size distributions between the two images.

(3) Even if the two images show different distributions and the one from the worked slurry has more of the smaller sized particles you have to establish that the difference is a result of a slurry breakdown, and not something completely unrelated (random fluctuations - these can be dealt with more and larger samples; systematic errors, e.g. different sedimentation times when picking the samples - those are much harder to identify and only explicitly acknowledging the possibilities and the steps taken to deal with them are good enough to establish credibility that you know what you're doing).

Either of these is sufficient to warrant the labels 'useless' and 'meaningless' that I chose to attach, the three of them together make

Originally Posted by Woodash

Personally, I don't think this stuff is useless at all.