Nubatama Synthetic Stones - First Look

It's a Nubatama Bamboo series 150 grit synthetic waterstone!
So what does that mean? And where and when can you get it? And even more importantly, how well does it work?

The logo on the saya and the logo on the stone is the Nubatama logo. It is the brand name. Much like Shapton, Naniwa, King, etc.

The other logo - the pentagon with the Kanji in it - is the 'bamboo' series of stones, much like the Shapton Pro or Chocera series of stones. There will also be a second series of stones - the 'Plum' series.

So while this stone is quite interesting in it's own right, it is but one stone of two series of stones that I am importing from Japan.

As I am typing this, an initial order from Japan is heading to Mark - at ChefKnivesToGo, who will be carrying the full (and extensive) line of these stones. Two of the stones in this order were not ready for shipment (both 150 Bamboos), so they were sent to me via EMS and I received them more quickly - the first Nubatama arrivals. A second shipment of stones - one each - was also sent to Tom of Jende Industries, and since he is much closer, I expect that he will have them any day now. The suspense is killing me.

When Mark's order arrives, they will be made available for sale.

I also intend for these stones to be made available for use on the Edge Pro and in time for the WEPS as well.

I'll have more to say in the future about the design of these stones, the goals of these two series, etc.

OK so how well does it work? Well I'll put up my first review of this stone in a separate post, the first Nubatama Bamboo 150 stone. Hint: incredible!

The Japanese for Bamboo is 'take'. Not like take in English, but Ta plus ke.

The Japanese for plume is 'ume', pronounced OO me, with the 'e' soft like the e in home, not hard like me. Take also has a soft 'e'.

So you can call these stones bamboo or take

or plum or ume.

Use Google translate to hear what the words sound like if you wish. Click on the speaker icon to hear the words.


How to say 'bamboo' in Japanese


How to say 'plum' in Japanese


Stone review next!

CBN Cubic Boron Nitride - Scanning Electron Microscope (SEM) images

In the previous posting, Part 2 : A Comparison of Three "Quarter Micron Polycrystaline Diamond" Slurries, I mentioned that I sent out seven samples to the SEM facility for analysis. Six of them were quarter micron monocrystaline and polycrystaline diamond formulations. The seventh sample, which was not included in either Part 1 or Part 2 of the above study was 0.125 or eighth micron Cubic Boron Nitride, abbreviated as CBN.

My CBN products are available along with all of my monocrystaline and polycrystaline diamond products at Ken's Corner.  This is an area set aside for some of my products that are sold through Chef Knives to Go.

CBN is available at  Chef Knives to Go in 0.75, 0.50 and 0.25 micron sizes as well as my finest CBN 0.125 micron product. I had SEM micrographs of the finest particle size made at various resolutions that demonstrate both the consistency of particle size, the purity of the preparation and shapes of the individual particles. Also of note is the complete absence of any agglomeration of the slurry.

Agglomeration is the clumping together of individual particles into larger structures which would result in effectively making a coarser grit mixed in with the slurry. In colloidal suspensions, this process of agglomeration is also referred to as flocculation . A good example of this would be curd formation - where the cottage cheese curds separate from the whey in milk  Flocculation is also advantageous in brewing and sewage treatment, but to be avoided at all costs in abrasive particle preparations. Agglomeration or flocculation is more likely to occur as particles get smaller as the surface area to volume ratio increases and electrostatic charges become greater. To reduce this effect of agglomeration, the absence of charged particles in the carrier is essential and the reason for using deionized water in these preparations. You do NOT want to dilute these CBN or Diamond slurries with tap water and the deionized water used is of the highest purity, 'cleaner' than filtered water. Also, too high of a particle concentration can increase the odds of agglomeration. In the process of formulating my compounds, several concentrations were tried to see where these limits were. My preparations are well enough below these limits, taking into account dehydration over time.



The samples were prepared by mixing the bottle before use and spraying a light coating of the slurry from the atomizer bottle that the product comes in. This sample is allowed to dry on standard metal cylinders used for mounting samples for SEM analysis - the same conditions as you would see on a strop sprayed with the product. As you will see in the micrographs, no agglomeration is present, just a carpet of particles.

SEM Images

I will present the images in order of increasing magnification. In each image a calibration bar is in the legend at the bottom of the micrograph This bar specifies the length that a particular number of nanometers or microns represent. Remember that 1 micron is 1000 nanometers, so 500 nanometers would be half a micron for instance The magnification is also noted to the left of the measurement bar.

This first image is taken at lower magnification, 2,000 times magnification or 2.00 KX noted in this image's legend. This is just beyond the limits of conventional light microscopy. The bar show how much distance in the image is equal to 5 microns. Of note is the carpet like effect of the particles, looking much like a layer of salt on a countertop. Not a thick pile of particles and not sparse particles, but an optimum distribution. Just enough to cover the surface with a nice layer with some 'light spots'.

Now let's go in a bit closer - 5 times closer -  first at 10,000X and then at 20,000X. At 10000 x the measurement bar would be 1000 nanometers so this first image is at a slightly higher magnification and the bar slightly smaller than 1 micron or 990 nanometers.

Now we can make out the individual particles and see the uniform coating of particles present.

Next is a 20,000X magnification image - 10 times closer than the first iimage presented,  with a 500 nanometer or half micron bar. The individual particles are more clearly resolved and you can see the surface characteristics of these particles.

Now, in Part 1, I showed Particle Size Distributions (or PSDs) of various diamond preparations. Here is the PSD of my eighth micron CBN product. Please refer to the Part 1 posting for a more detailed explanation of these graphs.

---

Ken

Part 2 : A Comparison of Three "Quarter Micron Polycrystaline Diamond" Slurries

The first part of this comparative analysis of quarter micron polycrystaline diamond slurries has generated a great deal of interest and generated some additional questions that I will address in the initial discussion of the second part of this posting. Then I will go on to show what these compounds actually look like under the microscope and describe the testing methodology and then discuss these additional findings.

CARATS

Apparently this picture described more fully in Part 1, deserves yet a third look. Just to be clear, the product on the left labeled OUR's is a competitor's product and the one on the right,  labeled  Their's,  is a product sold by a another vendor who I have the greatest respect for - both his products and his professionalism. He is considered by most in the industry to have the best products available. For that reason, I do not offer the same products he does. If you want the specific product he is selling I recommend you buy his product. It is a 0.25 micron monocrystaline diamond slurry.

The bottle on the right contains 21 carats of monocrystaline diamond. The bottle on the left was determined to only have 3.33 carats. My methods for determining this have been questioned.

The bottle on the right was determined to have 21 carats two ways. The most simple and obvious way was by weighing the carats that were put into the compound before it was formulated. The product is purchased by the carat weight. This of course is so obvious that it shouldn't even be a question - yet some have questioned it. If you want more carats, it costs more. Want less, it costs less. It's just like buying food in a grocery store by the pound. Weak solutions are cheaper and have less particles and therefore abrade less when used for sharpening edges. It is easy to show this. The only exception to this is if the product isn't what you think it is, but is an adulterated formulation. The honest way to sell product is to say how much of it you are selling, not disguise it in rhetoric about needing ideal compound concentrations in your product or a 'weak tea tastes better than strong tea' type of argument.

So what is the 'ideal concentration'? Some vendors are going for lower undisclosed concentrations, some only saying 'heavy' concentrations, some just not saying what their concentrations are at all and some even suggest that it cannot be determined. Surely they know what they are buying when they formulate it or have it formulated for them.  If they are not specifying their product concentrations, you are buying an unknown quantity of product. I have a bridge in Brooklyn that is on sale right now that I'm holding in reserve just for you. :)  (Or perhaps they formulated it themselves in their kitchen sink or worse?)  If they aren't telling you this information, either they don't know it or don't want you to know it.

The vendor on the right side of the picture above specifies his concentrations as 21 carats per 4 oz bottle. My products also have the same concentration..There is a reason for this concentration. My products were tested at various concentrations for a specific purpose - to give my customers a product of the highest quality and at a concentration not so high as to produce particle agglomeration. This applies to any of the particle sizes in the compounds that I sell.

Another way to determine the concentration of a sample is to take a known volume and dehydrate it and weigh the volume before and after dehydration to determine percent by weight loss. Some have mistakenly suggested that this was done by decanting the liquid off the top into a sink and weighing the remainder. Yet, even after saying this wasn't the case, they insist that it was. It's not how I do science.  My background includes over 25 years of research, and includes peer reviewed publications in electron microscopy, multiple disciplines of medicine, and computer science. I have also held faculty positions and run several research laboratories. I couldn't imagine doing something so unintelligent.

If a suspension based sample was dehydrated and weighed, perhaps some of the components of the suspension would remain in the sample. Think of this as marbles in syrup. My formulation uses deionized water and is a slurry, so there is no residue that would remain. Think of this as marbles in water. There is a reason I chose a slurry over a suspension which will be explained shortly.

You get an extremely accurate determination using this analysis technique with a slurry. How do I know this? Because if a known amount of carats is put in the sample, this test accurately determines it. It's just that simple. So this is yet a second way to determine that the bottle on the right is correctly specified as having a 21 carats per 4 oz concentration. The sample on the left does contain a "permanent suspension", so perhaps some residue might remain from simple dehydration much like dehydrated syrup would have weight. If this were the case, than it would have OVERESTIMATED the concentration of this product. BUT ...

This was considered in the determination. The testing methodology was done in a lab, not some home brew experiment. This lab does these types of determinations all the time and takes this into account. Diamond can sustain higher heats than suspensions can, so the high heat drying process reduces this artifact to a negligible level. Again if anything this would argue for the product on the left having even LESS carats. Perhaps 3.3 rather than 3.33 - but this is speculation. In short, this testing methodology is very accurate and is routinely used by this lab for testing both slurries and suspensions.

SLURRIES AND SUSPENSIONS

Much has been made of permanent suspensions. A slurry is simply particles floating around, much like the slurry we all use in our sharpening or honing when we use waterstones. These are water based slurries. Therefore it is a wet technique. Sandpaper is a dry technique, usually. Suspensions add additional components to their formulations, hoping to keep the particulates floating in a permanent state rather than settling to the bottom.  Using a suspension does help to keep the particulates from settling to the bottom, but this may not be an appropriate solution or answer for all abrasive requirements.

In particular for products used in dry hand or powered situations where the abrasive remains in a relatively fixed position, it is, IMO suboptimal. It is suboptimal, especially so for submicron particulates where the suspensions may actually interfere with the abrasive. I will show this later on in this discussion. For applications requiring continuous streams of abrasives in a liquid environment, it may be more appropriate, but in that instance, the suspension should be a true permanent suspension and / or have arrangements made to keep the particulates evenly distributed at all times - magnetic stirrers, various mixers, etc. This is irrelevant to the sharpening and honing processes used to sharpen edges by hand.

For PRECISE SHARPENING, as opposed to industrial systems using pumped abrasive based liquids for non-sharpening applications but rather part dimensioning applications and surface preparation, what is relevant is disbursing an even coating on a strop. Doing this is largely a matter of technique - NOT keeping the particulates suspended. A perfect permanent suspension does not guarantee uniform dispersion from a spray bottle.

Good technique optimizes uniformity and is far more relevant. Not even the most obsessed user will go to extreme lengths to do more than a visual inspection to set an acceptable level of uniformity of dispersed particulates. A good sharpener / honer can deduce uniformity from the feedback he receives and can adjust his technique - even at particle sizes as fine as 15 nanometers (1.2 million grit). If you haven't been there, it's just theory. I've been there. I'd like to see others join me there in the future.

This brings us to the topic of permanent suspensions. Are there permanent suspensions? Yes, there are suspensions that for all practical purposes are permanent, but yet in some there is settling that takes place. This first picture is an Alumina suspension. I have yet to see settling after several months. Next are two products that claim to be permanent suspensions - the two products that were compared in part one. As you can see this is clearly settling. It is visually obvious to the most untrained eye.

Now, a supposed 'expert' claims, "A permanent suspension may appear to one eyes as being separated or settled out however it is impossible for separation to occur even if one thinks it appears to be."  If that were the case, then 1) either these two products are not permanent suspension systems or 2) if the suspension is uniform, then the upper area reveals it to be of extremely weak concentration..

If I were to use these so called permanent solutions, I would most certainly shake them up before use. For hand sharpening or honing applications, it's just not that hard to redistributes the particulates by shaking the bottle gently a couple of times. Trying to believe that these bottles contain a uniform particle distribution that is as uniformly distributed as a freshly shaken slurry strains my sense of credibility. Just shake the bottle. It would be prudent and won't hurt anything .

Here's the truly permanent Alumina slurry:

It is uniform throughout.

Here are the two so called permanent slurries. I see two distinct regions. I can't imagine a reason not to mix it back to a uniform distribution as uniform as a freshly mixed slurry. Just can't.

And the second sample tested in Part 1:

I'll let the reader draw their own conclusions if they think these solutions don't require mixing - just like a slurry. In either case a suspension either must be truly permanent or you should remix before use. Remixing is just not a big deal for honing applications. It is a minor task - nothing more and certainly not a reason to avoid slurries.  Application technique is far more important. What's MUCH more important is making sure that the individual particles don't stick together in big lumps. This is called particle agglomeration.

PARTICLE AGGLOMERATION

Particle agglomeration is one of the sins of using particulates for sharpening or honing applications. Indeed it is a sin for any type of sharpening application and to be avoided at all costs. Why? Well if two particles each a quarter micron in size stick to each other, they act like a half micron particle (yes, this is simplified, ignoring shape characteristics, etc.). If four particles stick together, it acts like an even coarser particle. This is even a worse problem than particles of random sizes or a very broad distribution in a slurry or suspension. Of course you can have both problems.

Now as the particles get smaller, the suspension can interfere with the particulates. If it is not designed to be used for the intended application, it may contribute to particle agglomeration as you will soon see. Charged particles in solution or ions can greatly contribute to this problem as well. For this reason, charged ions in the slurry solution will cause particle agglomeration and this one reason I specifically use deionized water for the vehicle. The other reason is that when it evaporates, it leaves no residue, as previously discussed.

My preparation is meant to be used as a dry technique, not a wet one. For edge sharpening, a wet technique offers no advantage. I know this from experience, based on years of sharpening.

One of the techniques I use is to take the slurry from flattening a synthetic stone and applying it to paper or balsa and letting it dry, effectively creating sandpaper that has the characteristics of the stone it came from. I have used this technique for coarse 120 grit stones through 30,000 grit stones. Again it is a dry technique. The results after years of use on many synthetic AND natural stones is that the abrasion characteristics are even finer than using the stones that they come from using a wet technique.

For dry techniques, lubricity has NO place in the discussion. The particulates become embedded in the substrate - balsa or paper and the results are excellent. This is the principle employed in platens, where the particles stay in place as the material being abraded is drawn across the bed of particles removing metal in the process. Now when you use a suspension that has been dried, it is only of modest concern for coarse particulates, but as the particulates go down into the submicron range, it becomes a disadvantage, literally gumming up the works, submersing the particulates in 'gunk'. This may be fine in a wet system, but not in a dry system. Simply put, it is the wrong tool for the job.


Is this simply idle speculation on my part or based on hard scientific data? I'll let you decide.

In the first part of this post, the particle size distributions were determined. This was a good first step in preparation for the next part of this post - actually looking at the particles themselves. Direct observation of these particulates is beyond the range of a light microscope. A transmission electron microscope is also the wrong tool for the job. A perfect tool for the job is a scanning electron microscope or SEM, which easily resolves particulates in the nanometer range. A quarter micron or 0.25 microns is a 250 nanometer particle. This will be useful to know when interpreting the following micrographs.


Seven samples were sent to the SEM facility of a major university. The person performing the analysis did not know anything about the samples. They were simply numbered one through seven. Each sample was shaken before extracting the samples that were sent to the lab. The containers were never previously used and specifically used for containing microabrasives. The instructions were to shake each sample and spray small stubs that were inserted into the microscope's chamber, which is a high vacuum environment. A light spray was applied to each stub and the sample was dried in a manner appropriate for placing it in a vacuum environment. The resolution of the scope was calibrated prior to taking the micrographs to assure very accurate measurements. You can see the bar at the bottom of the micrographs with a number next to it indicating a distance, usually in nanometers. Thus if a 1000 nanometer or 1 micron bar is present, a quarter micron particle would be a fourth as long as the bar. These bars are extremely important in evaluating the images and accurately sizing the particles.


So what do you look for? Well, you look at the shapes of the particles. Are they consistent? Are they the right size? Are they cleanly separated from the other particles or stuck together in lumps? If there are lumps how big are the lumps. remember if a lump of particles or an agglomerate is a mass of particles that is 8 microns in size, even if the individual particles are a quarter micron, you are looking at a slurry that will give an 8 micron finish or 2000 grit.

What were the samples?

There was a monocrystaline quarter micron product - the product that appears in the first image in this post.

We will call it sample one. It is a slurry using deionized water.


The second sample is my product - a quarter micron polycrystaline product. Also a deionized water preparation.


The third sample is a 0.3 micron Alumina permanent suspension


The fourth sample is advertised as a quarter micron polycrystaline diamond preparation in a permanent unspecified suspension.


The fifth sample is a water based suspension, also advertised as polycrystaline diamond.


The sixth sample is an oil based suspension, also advertised as polycrystaline diamond.

The seventh sample is eighth micron CBN. It will be shown elsewhere and is not a part of this study.

SEM IMAGES

This is sample one , quarter micron monocrystaline diamond deionized water slurry

The bar at the bottom of the image shows a 500n (nanometer) or half micron 'ruler' bar, magnification at 20,000 x an image number and the voltage of the beam, 15,000 volts. Here we are looking at clearly defined particles of an appropriate size. They are very uniform in size with no agglomeration. Just clean particles. Exactly what we want. It is clearly monocrystaline diamond. It is textbook perfect high quality product.


 Next is my product - a quarter micron polycrystaline product in a deionized water slurry:

Note the 333n or third micron bar, slightly different than the previous image. 30,000 x magnification. Again, individual particles of appropriate size, a uniform particle distribution, no particle agglomeration. Clearly polycrystaline diamond. A product I can easily stand behind and feel comfortable putting my name on.


Next is the 0.3 micron Alumina permanent suspension

At the same magnification as the previous image. Particle sizes are appropriate, but with a bit more variation not so tightly controlled and some degree of agglomeration. Individual particles are still clearly recognized
Clearly an alumina suspension.


Next is the Polycrystaline diamond preparation in an unknown suspension. The range of particle sizes required several micrographs at various magnifications.

 Note the scale factor of 50 microns! Only 200x magnification. The large structure in the middle that looks like you are looking down the throat of a volcano is more that three barlengths across or 150 microns - not nanometers but microns. To give a comparison a 120 grit glassstone particle has particles of 123 microns, so it is a coarser particle than the particles used in the coarsest stone Shapton makes.! There are other large particles clearly greater than anything you would want in as quarter micron preparation. No particular uniform size just pretty much random debris, not identifiable as being any particular type of abrasive.


Here's a closer look at the same sample

 The scale factor is still hugh - 10 microns!. Remember that 1 micron is a tenth the length of the bar and a quarter micron would be 1/40 th the length of the bar. This object is at least 12 bars long or 120 microns, similar in size to the 120+ grit 'volvano' It is a glob of something not clearly identifiable, not at all looking like my polycrystaline diamond preparation. As of yet, no one has identified what the glob is made of.


Let's get closer:

Now we are looking at a 1 micron bar and should be expecting to see particles 1/4 the length of the bar, but instead are presented with a closeup of this blob. Hardly any freestanding particles to be seen. By now you should be reading these yourself pretty well.
 
Here's one last overview.at 200 microns. This crater valley is strewn with hugh lumps of 'stuff'

Now the other product reviewed in the first part - the one with two humps in the particle distribution This is the water based suspension

At a 1 micron measurement bar, the particles are almost identifiable, but still look stuck together in clumps, with the clumping probably explaining the bimodal distribution. Clearly not ideal but not what I would want to use compared to my product with distinct particulates.


Now the oil based version of this product

 At a half micron measurement bar size, we can see than the particle size fills the screen, which is fully compatible with the hugh particles picked up by the particle analyzer data.

 SUMMARY

It's a lot of information to digest in this posting, so lets summarize what we found out. We began by reviewing my testing methodologies showing that I have very accurately measured carat concentrations. Then we reviewed slurries and suspensions, showing that not all suspensions are the same and that some suspensions should be mixed up before use, just like slurries, but that the application technique to the strop was of far greater importance. While suspensions are most useful at coarser grits, at finer submicron grits, their use, particularly when the product is used in a dry preparation may actually hinder the product's use causing massive clumping and agglomeration. This may or may not be the case for liquid preparations used in abrasive flows, a topic not addressed in this discussion because it is not applicable to sharpening / honing of edges. Then we actually look at the preparations. The slurry preparations showed distinct particulates, while the suspensions showed a very moderate amount of agglomeration when used in a dry state (alumina peparation that showed no evidence of settling) to severe agglomeration, to the point where it was difficult to even recognize the particulates as even being diamond or alumina or something else. There are electron microscopy techniques for performing elemental analysis, such as EELS (Electron Energy Loss Spectroscopy), but at this point I, and I hope the reader can clearly see why I consider my products to be of the highest quality available. ALL of my particulate products have undergone this level of testing, assuring my my customes of a most pleasant and rewarding experience. I am serious about providing a quality product specifically designed for producing superior edges and I hope you can see that what goes into my product, including the level of research and the rationale for it's design, is what separates it from it's competition.

Finally, I have to say the most basic statement about my products. They work. My customers love the edges these compounds produce. In the end, that's what matters most to me.

If you have gotten through both postings, I truly commend you and know you are serious about your edges. Thank you for your time reading this.

---
Ken

Part 1 : A Comparison of Three "Quarter Micron Polycrystaline Diamond" Slurries

"When you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely in your thoughts advanced to the state of Science, whatever the matter may be."
Baron William Thomson Kelvin 1883


"Quality is remembered long after the price is forgotten."

Among a series of products I have come out with for sharpening knives and honing razors, one of my products is a Polycrystaline Diamond product that is a quarter micron in size  I will announce my other products in a separate announcement. Among my diamond products I carry finer particle sizes in both monocrystaline and polycrystaline. I do not carry the monocrystaline product in the quarter micron size.Why not? Because there is an existing product of excellent quality already on the market that fills that role superbly. I could not improve upon that product and I endorse it's use. It is made by Hand American by my friend Keith. This product, along with all of his other products including half and one micron monocrystaline diamond, are of the highest quality - I use them in my knife sharpening service and they are an essential part of the products I personally use.

So for my coarsest diamond product, quarter micron, I chose to carry a quarter micron polycrystaline products. Why? Because the available products did not meet my standards of quality. For the finer sized grits, I carry both monocrystaline and polycrystaline.compounds. I believe that both have advantages and disadvantages and feel that my customers can make choices as to what best fits their technical and cost requirements.

In the first part of this study, I have had three products evaluated - mine and two of my competitors' polycrystaline diamond products. Both of these vendors describe their product as containing 'Dupont' Polycrystaline diamond in their product. They both offer a quarter micron product. Neither vendor specifies the concentration of diamonds in their product precisely referring to it as either 'heavy' or 'medium'. Both vendors advertise their product as having their particles in suspension and not requiring shaking.

My product contains 10.5 carats per 2 ounces. I know it does because I pay by the carat for my product and I specify this custom formulation. I had to have my products tested in this particle size - and smaller - to see if in fact I could make it more concentrated and still have it perform to my specifications. One of the issues of concern is particle agglutination or particles sticking together. It's why the vehicle is deionized water - no particle agglutination. My product DOES  require shaking, but as you will see all three products require shaking before use.

In addition to concentration, two other important characteristics are:

The actual particle size. What is the average particle size and how much does the particle size vary?


What the particles are actually made of - are they in fact polycrystaline diamond? Or even diamond at all.

OK so let's start at the basics. What is a carat? One carat is a fifth of a gram. It is a measure of weight. 21 carats is therefore 4.2 grams.

One ounce is 28.35 grams. Four ounces is 113.4 grams. So if you have 21 carats in four ounces, you have 4.2 grams of diamonds in 113.4 grams of water.. This is a concentration used in both Hand American diamond products and all of my products.

Here is a photograph of the Hand American product being compared to another product in this review, The photograph was taken by one of the vendors to compare products, showing an 'ours vs theirs' comparison. There was the clear implication that 'ours' was better than 'theirs' because 'ours' had a 'heavy concentration'. The third vendor's product in this review also has a creamy white consistency quite similar to this vendor's product.

This picture deserves a second look.

 What you see at the bottom of the vial on the right is 21 carats of diamonds taken after the slurry has settled for days vs an unsettled sample on the left. The 4 ounce bottle on the right is compared to the 2 ounce bottle on the left. So how many carats does the bottle on the left have? If it were the same concentration it would have half as many carats or 10.5 carats. I was curious to find out. I was curious to find this out of the other vendor in this study, but the results of the particle size determinations were so disappointing that I lost interest and didn't bother testing it. More about particle sizes in a moment.

Carat concentration can be determined by weighing a known weight of solution, drying it and weighing what remains to compute the percentage by weight. This test was done on my product and this vendor's product.

The results. My product showed 3.82% versus 1.21 % . Results were weighted to within one ten-thousandth of a gram. Put another way, the competitor's product contains almost a third (32%) as much carats as my product!

So my competitor contains 3.33 carats vs 10.5 carats of 'product' in my solution.

So to put this in perspective, going back to the above picture, the bottle on the left contains a sixth as much as the bottle on the right! Pretty amazing stuff!

So the 'white stuff' isn't diamond at all - it is the liquid suspending the 'diamonds'. The 'Heavy concentration' product actually contains a third the amount of my 2 oz bottle and a sixth the amount of the 4 oz bottle in the picture. I should be charging three times the price for my spray based on carat weight determinations alone!

So let's talk about Dupont's polycrystaline diamonds. Naturally occurring polycrystaline diamonds are exceedingly rare and expensive. Dupont in the 1970's developed a process for creating polycrystaline diamond from carbon synthetically (not a natural product). This technology was sold to another company so technically Dupont doesn't make the product any longer. The process has been refined and the resulting polycrystaline product is NOT white, but black. I have samples of this product in a liquid preparation. It is light grey in color - not white. The process involves an explosion at very high pressures for a very short duration converting the graphite to 'Dupont' polycrystaline diamond. Again this name is obsolete. Both of these vendors refer to their product as containing 'Dupont' polycrystaline diamond.

Particles - how big are they and what are they? Well it turns out that particle sizes can be measured quite accurately. Using an extremely accurate lab instrument, a laser scattering Particle Size Distribution analyzer or PSD for short, you can measure the particles in a slurry and tally them up, computing the average particle size and how many particles of each size are in the slurry. You can graph this out as a bar graph or as a curve, with the bar graph showing the amount of particles in each size category and the line showing - starting from the smallest detectable particles a cumulative total of the amount of particles. From this curve, you can show where half the particles are size wise for instance by locatiing when the line crosses 50% - or any other percentage along the curve.

Here is a PSD of my quarter micron Polycrystaline diamond product. I have this analysis of my products, including my CBN products.




Here's the details:
Mean particle size 0.22 microns (0.09 - 0.59) microns.

What does this mean? If 16000 grit is a 1 micron particle  0.22 microns is an average particle size of 73,000 grit. Quarter microns would be  64000 grit so it is within specification - actually finer.


Here is another competitor's product PSD report




This one actually has TWO humps. In all likelihood it is an impure mix of compounds.


Here's the details:
Mean particle size 20.09 microns (0.51-229) microns. Very low carat weight Polycrystaline diamond mixed with Alumina and other 'findings'. So the average particle size is 800 grit! The largest particles in the slurry are an astounding  70 grit particles !!

After seeing this, the concentration determination was pretty meaningless to bother with.


On to the last product. I had the test repeated twice to test the accuracy of the testing procedure and to be sure the sample was properly and consistently tested

Here's the details:
Mean particle size 0.37 microns (BOTH RUNS) 
Range (0.12-1.32 microns) first run, .(0.10-1.73 microns)second run.
 No more than 0.05% POLYCRYSTALINE diamond is in this product with the remainder either monocrystaline diamond or alumina!


Converting this to grits, this mean particle size is 43,000 grit.or right inbetween a quarter  (64000 grit) and half (32000 grit) micron particle.

Or to compare it to my product which is 73000 grit, 48000 grit is 1.5 times coarser ! The largest particles in this product are 2-3 times the size of the largest particles in mine.

My product is 100% polycrystaline diamond.

SUMMARY

So I presented a lot of data here comparing three products claiming to be polycrystaline diamond. I gave detailed analyses of all three products - mine, and vendors one and two. One vendor had truly horrible specifications when subjected to particle sizing distribution analysis (PSD), so much so that no further testing was performed. The second vendor's product contained less than half of one percent polycrystaline diamond with the remainder either containing either monocrystaline diamond or alumina. Given the color of the product and that neither mono or polycrystaline diamonds are white, I suspect the later although further testing is in progress to provide more detail on this point.(Stay tuned for part two). The concentration of this mix of particles in total was a third of mine and had an average particle size one and a half times larger.with the largest particles noted as large as 1.7 microns or  over 9000 grit.

So given these analyses, it is probably worth asking if any of you reading this have actually tried REAL quarter micron Polycrystaline diamond yet?

Here's a picture of my product. Each batch is given a lot number for quality assurance purposes and I put my name on my product.

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Ken

Atoma Diamond plates on Sale NOW!

Guys, it's been crazy busy lately and I'm just getting a chance to get my head above water to start posting some products. I've had these 140 grit Atoma plates sitting around for over a month now. Expect to be seeing a lot more activity in my Subforum!!

Charlie first recommended these Atoma 140 plates to me a while back (about a year ago) and I noticed them when I visited Tanaka Toishi, so I had some included in my last two stone orders (more about this later - I have a bewildering array of natural stones in house too, from very affordable to very exotic. If I don't have just what you want, let me know and I'll do my best to get it!)

Here in the USA the Atoma plates have been quite expensive and I saw an opportunity to get them here primarily for the American customers (and fellow knifenuts worldwide). While they are more expensive than the DMT plates, they certainly do have their place.

Charlie did point out to me that these 140 grit plates are more aggressive than the DMT XXC plates and their dot pattern allows for less stiction. Thank you, Charlie! I've recommended these lapping plates to those in that part of the world ( e.g., Australia) for a long time too. Now I can bring them to KF members at a reasonable price too.

My biggest objection to these has been their price. But I believe I have partially solved that problem.



For Knife Forum members, I'm selling them at the introductory price of not $110 each, but an incredible $99 each - with free shipping in the USA!!

For the replacement diamond surface plate, I'm selling this to Forum members at the introductory price of $80 each - also with free shipping!! Normally this is attached as a replacement to the aluminum base plate rather than buying the base plate when the diamonds eventually wear out.


Overseas orders will get a shipping price reduction comparable to the USA shipping charges.

Send me a PM on knifeforums for details and the discount or email me at 'ksskss at earthlink dot net' for details.

If anyone is interested in mounting the replacement plates to a variety of bases, I can offer this service as well.

PM or email me for details on overseas shipping and mounting options.

They are in house and ready to ship. If anyone is interested in other grits or custom modifications, just let me know. I'm pleased to add this product to my increasing line of products. Stay tuned for a LOT more announcements!


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Ken

Tanaka Toishi Kogyosho Exclusive Distributorship

Major announcement regarding JAPANESE NATURAL STONES!

Tanaka Toishi Kogyosho exclusive distributorship

As many of you know, on my last trip to Japan I visited Kyoto. Since that time, I have had many conversations with Tanaka, the sixth generation owner of Tanaka Toishi Kogyosho.

At this time, I am extremely pleased to announce that Michiaki Tanaka has selected me to be their sole distributor for their products, which include a broad selection of natural stones. This sole distributorship is for North Americas, which includes the importation of their products to the US, Canada, and Mexico. It does not exclude selling their products to other countries as well.

I am extremely proud and honored to have developed this relationship. In the coming days and weeks I will be developing a web presence regarding these products. I will be working closely with Mark of Chefknivestogo to help promote these products so expect further upcoming joint announcements. I am certainly interested in knowing what you, members of this forum, are interested in in terms of natural stones. I will be developing both a knowledge base of information about these fascinating stones as well as a selection of stones to choose from. While my primary focus will be towards the use of these stones for knife sharpening, it will be expanded to include sharpening straight razors, woodworking (and other) tools and sword polishing stones. I'm looking forward to a cooperative arrangement with other vendors as well as customers.

These stones will be primarily oriented to people who use freehand sharpening techniques, however there will also be announcements regarding the use of a select few natural stones for precision guided devices as well. There are other products that Tanaka carries, so expect to see other interesting product introductions in addition to natural stones too.

This announcement does not in any way mean that my current ongoing vendor relationships will cease. In fact you can expect them to expand as well and I look forward to additional cooperative ventures, which will be the topics of additional postings.

Dealer inquiries are welcome.

As many of you already know natural stones are quite unique and individualistic, unlike synthetic stones, so if you are looking to acquire specific types of stones, please let me know and I will help you find them. In some instances certain rarer stones will be unavailable, but there's no harm in asking.

Not only is the Tanaka family a seller of fine natural and synthetic stones, but they are also producers of natural stone.

They are owners of their own toishi-yama in Kameoka City, which is a source of natural stones.

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Ken

Precise Sharpening

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