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TOPIC: A theory of how the WE diamond pastes work

Re: A theory of how the WE diamond pastes work 2 years 3 months ago #2555

  • wickededge
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We're finally getting some where with the images. Below are two pictures; the first is of the edge after 1000 strokes with the .5um spray and pasted diamond and leather strops, the second is of the edge after 100 strokes with the 1um spray and pasted diamond and leather strops. I purposefully angled the strokes with the 1 micron strops so we could easily distinguish the scratches. The microscope is angled so that there is minimal reflection from the flat surface and maximum reflection from the scratches:

halfmicron-510x-1280g.jpg

.5um Diamond Spray/Paste and Leather Strops - 1000 passes
View the Full Sized Image

1micron-510x-1280a.jpg

1um Diamond Spray/Paste and Leather Strops - 100 passes
View the Full Sized Image
--Clay Allison
Last Edit: 2 years 3 months ago by wickededge.
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Re: A theory of how the WE diamond pastes work 2 years 3 months ago #2559

  • PhilipPasteur
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Trying to reply.. test.
I did this earlier and typed the same long note twice. I hit submit and was taken back to recent threads.. Looks like nothing got posted. Trying this before I spend the time to re-compose my thoughts.

Phil

Edit, looks like I am getting through... now to figure out what I said a couple of hours ago :)
Phil

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Last Edit: 2 years 3 months ago by PhilipPasteur.
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Re: A theory of how the WE diamond pastes work 2 years 3 months ago #2560

  • PhilipPasteur
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Ok...
The latest pics are great... WOW !
It becomes obvious that the angle and lighting are really important in capturing micron level scratches. We are seeing abrasions now that were basically invisible before using the same abrasives and equipment. Obviously we can't depend on a single series of photos to make hard conclusions on what is happening at the micron and below levels.

I do have a question though. I think that I know part of the answer, but that still clouds the issue a bit. You mention using both the WE pastes and some equivalent micron sprays. I think we have seen that compounds calling out the same level of abrasives at this small a grit size, are not all created equal. The actual distribution of abrasive sizes are not typically the same. I have not seen the size distribution published for the WE pastes, nor the sprays that were used.
I think I heard Clay say (or read actually) that he was using the sprays as a sort of lubricant to attempt to remove stiction and the resultant (theoretically) burnishing of the metal from the mix. This is a good goal, but using two compounds adds additonal variables to the mix. Where did the scratches come from?
Do I need to use both abrasives to duplicate the results?

In any case, I am very happy to see that these abrasive really do "abrade" and do something to the metal other than just "magic". I think we mostly agree on the results at the edge... it is just that seeing what is happening that is somehow comforting.. :)

Phil
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Last Edit: 2 years 3 months ago by PhilipPasteur.
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Re: A theory of how the WE diamond pastes work 2 years 3 months ago #2563

  • jendeindustries
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An excellent thread, my friends!!! :woohoo:

As a long-time Shapton fan, I almost read this entire thread saying to myself "I told you so!" :evil: I've never been into pastes or sprays precisely because of the fact that Shapton goes to 30K. Just ask Ken how hard and long he had to twist my arm to even try the .125 CBN.

I see some patterns developing here:

1. Going to the current lineup of pastes and sprays off the 1K Diamond WEPS is not the most productive choice in a forward moving progression that aims to eliminate the previous grit's scratches. However, for "polishing the grooves", and leaving a more toothy, yet clean edge, it is.

2. While there is no doubt that the WEPS pastes are of their advertised grits, Ken Schwartz and HA products have more concentration of abrasives, which enables them to cut faster regardless of the medium.

3. Polishing and sharpening are two different animals. Sharpening employs the use of scratches, polishing works to minimize them, hence the various concentrations of abrasive in different polishing compounds for the different markets (an area where Mark's blog is currently venturing). For example, jewelers rouge is not as concentrated as Ken's CBN because you want to preserve the precious materials on jewelry by making a uniformly smooth surface, not to establish a plane of perfectly aligned scratches that resemble North Korean Soldiers. The Dovo paste is not an aggressive/hard abrasive because you don't want it to quickly abrade through the very thin edge of the edge of a razor. Abrasive concentration also heavily influences the price, which should go without say about now.

Overall, I'm beginning to conclude that what I thought before has become an even stronger argument - and that is to progress as far as you can with stones and then use the pastes/sprays to "polish the grooves" the last stone's scratches rather than to attempt to establish a "true" grit edge with them.
Tom Blodgett
Jende Industries, LLC

My Blog: jendeindustries.wordpress.com
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Re: A theory of how the WE diamond pastes work 2 years 3 months ago #2564

  • mark76
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PhilipPasteur wrote:
Bottom line is if we are seeing metal come off of the blade there is some amount of abrasion going on.

I wonder if perhaps the equipment that we are using to photograph the steel is just not enough to pick up visual evidence of what is really happening.

I think Clay said at one point that his Dino at 400X only had resolution that was in excess of 1.5 microns per pixel. Mark, your at 250X has to have even less resolution. Between that and the problems that we all have getting the lighting just right, maybe you just can't see what is really happening. Of course, you should be able to see 14 micron scratches wso we can probably deduce from the fact that you do not that the scratches are smaller than 14 microns, maybe smaller that the 2.5 or so micron resolution that your shstem can probaly detect, but there is direct evidence on the paddles that abrasion is happening. That metal is coming from somewhere... Perhaps we just need an SEM at 2000X or better to really see what is happening.

Good questions about the limitations we face with our equipment, Philip.

But to prevent any misunderstandings: I am not saying the Wicked Edge pastes or the Dovo green paste are not abrasive. My strops get dark from steel filings as well. It is not a matter of either abrasion or burnishing, it is a matter of both. The stropping compounds just vary in the amount of abrasion and the amount of burnishing they cause.

I have slightly edited my post on the Dovo paste to reflect this. It was certainly not my intention to suggest this paste doesn't do anything at all.

Then the microscope. My Veho microscope is advertised to have a 400x magnification and a 2MP CMOS lens. But I don’t know what 400x means; I can get a much higher magnification simply by using a bigger monitor. And the 2MP figure is obtained by interpolation, so that is only useful for marketing purposes.

I take pictures at a resolution of 1280x960 pixels. At the “400x” level, I then see a piece of the edge of about 0.9 mm. That means each pixel represents about 0.9 mm / 1280 pixels = 0.0007 mm or 0.7 mu. However, it appears to me that the optical resolution is about two pixels, so the smallest spots I can see are about 1.4 mu. (That means the microscope has an optical resolution of 640x480, i.e. 0.3MP. This is quite low, even for a cheap microscope, but since we are looking for the limitations, let’s assume this is the actual resolution.)

Fortunately we are not looking at small spots, but at tiny scratches which usually have a similar size and are quite evenly spaced. And fortunately the human eye and brain are very good at distinguishing patterns, both the collection of dots that together represent a scratch, as well as the collection of scratches produced by a stone or strop that abrade an edge. So in practice we can seen scratches much smaller than 1.4 mu. I am impressed with the pictures Clay has posted of 0.5 micron scratches (or better: scratches caused by 0.5 micron diamond particles; the scratches are probably smaller). But yes, when things get even smaller we’ll eventually run into the limitations of the resolution of the microscope.

A more serious limitation I’ve run into already at the level of 3 mu scratches (or so) is caused by the lighting. Sometimes the angle between the microscope and the edge of a blade is such that the scratches don’t reflect the light enough. That simply means the scratches hardly or not show up at the pictures. The good news is that I can recognize the situations at risk quite well. They are the pictures in which scratches seem rather shallow, light is reflected in all directions and the pictures are generally grey or have a lot of spots of quite different shades of grey close to each other. The bad news is that I cannot always prevent it. I still have to experiment more with the microscope.

That is one reason why it is important that experiments are repeated, preferably by different people who have different equipment.

A third problem is that of contamination. Cross-contamination between strops is often mentioned. But quite often you simply don't know where the contamination came from. I have stropped with clean strops that came straight from th plastic and already caused some scratches.

So if anyone has got a cleanroom and a scanning electron microscope up for grabs... ;)
Last Edit: 2 years 3 months ago by mark76.
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Re: A theory of how the WE diamond pastes work 2 years 3 months ago #2565

  • mark76
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wickededge wrote:
We're finally getting some where with the images. Below are two pictures; the first is of the edge after 1000 strokes with the .5um spray and pasted diamond and leather strops, the second is of the edge after 100 strokes with the 1um spray and pasted diamond and leather strops.



These are the first really good photographs of the effects of 1 micron and 0.5 micron compounds I have seen in my life. Great!

The research program you're carrying out with an external institution sounds interesting. Would you care to tell us a little more about it, Clay?
Last Edit: 2 years 3 months ago by mark76.
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