Thread: Dry Honing

Originally Posted by GollyMrScience

As a point for consideration.
Garnets suspended in slurry will have a different sharpening action than those locked in matrix.
As the blade moves across the stone of a locked matrix the garnet abrasion will be along the metal side facing the stone. So on one side of the blade.
When the garnets move up into a slurry you now have garnets working the edge facing the stone and garnets abrading the leading edge of the blade as they are pushed ahead and dragged under the edge during a honing stroke. You will still get the greatest abrasion on the side against the stone and subject to the weight of the razor but this leading edge abrasion may have a smoothing action on the leading edge that will affect the nature of the cutting action.
Can't speak to that as my experience has been with trying to stop that kind of abrasive action in industrial use.
Just observing and now formulating a test or two.
What fun!!

I agree with this, at least as far as my non-scientific observations go. So dry honing would involve using only the exposed parts of the garnets. Honing with plain water and no slurry might cushion the cutting effect of the garnets a bit, and lather would provide even more cushion.

Josh

Originally Posted by Russel Baldridge

Ah, I see, it very well could be that mine is a softer specimen. In order to maintain a "just water" set of strokes, I have to change the water every twenty strokes or so.

Wow, that's soft. Even my Belgian blue isn't that soft.

Originally Posted by Russel Baldridge

The commonly agreed on difference between the old and new stone is amount of garnet right? So maybe it being an older "model" means the garnets are released more rapidly since there are more touching the blade per stroke. Just a theory, maybe incorrect.

I'm not sure what the consensus is on this. I don't usually follow the hone comparison threads.

The slurry that you're seeing is actually mostly the matrix that holds the garnets. The garnets themselves are red, if I remember correctly. The garnets are a relatively low percentage of the hone. So the slurry is (just making up numbers here) like 80 percent of the soft matrix and 20 percent garnet.

I think the blue hone has a much higher garnet concentration, but they are bigger and less aggressive than the coticule garnets.

Originally Posted by Russel Baldridge

Anyway, I guess what matters is that we are each achieving our own desired goals. And that deserves a "cheers".

That's what it's all about. You have to take everything you read about natural hones with a grain of salt, because they are all unique.

Josh

Originally Posted by JoshEarl

Wow, that's soft. Even my Belgian blue isn't that soft.

Well, I change the water when I "think" I see a haze building. Surely overkill, just for the sake of precaution, so It may not be as bad as I've made it out to be.

Originally Posted by JoshEarl

I'm not sure what the consensus is on this. I don't usually follow the hone comparison threads.

The slurry that you're seeing is actually mostly the matrix that holds the garnets. The garnets themselves are red, if I remember correctly. The garnets are a relatively low percentage of the hone. So the slurry is (just making up numbers here) like 80 percent of the soft matrix and 20 percent garnet.

"The traditional yellow stone ...contains 35-40% garnets"

And if I remember correctly, the older stones tend toward the upper ranges of that figure, so it is really not that low of a percentage in most cases.

Originally Posted by JoshEarl

I think the blue hone has a much higher garnet concentration, but they are bigger and less aggressive than the coticule garnets.

The Belgian blue "...consists of about 30% garnets and is therefore a bit less aggressive than the yellow stone but, on the other hand, more durable."

"Garnet crystals are a rhombic dodecahedron, similar to a soccer ball, with a surface of facets. The facet edges are sharp but obtuse. The roughly 15 micron grains will only penetrate your steel 2-3 microns."

These quotes were taken from http://pacifi.ca/Temp/BBHistory.html and so what we would conclude is that there is one size of garnet crystal and the cutting action depends on how many are in the slurry, the looser matrix of the blue stone allows more to be released while the coticule holds on to it's garnets and provides a more polished edge than the blue.

I seem to remember something about pink coticules as well, maybe they are very densely packed with red garnet?

Originally Posted by GollyMrScience

You will still get the greatest abrasion on the side against the stone and subject to the weight of the razor but this leading edge abrasion may have a smoothing action on the leading edge that will affect the nature of the cutting action.
Can't speak to that as my experience has been with trying to stop that kind of abrasive action in industrial use.
Just observing and now formulating a test or two.
What fun!!

Maybe the leading edge abrasion does smooth out the cutting edge, but essentially that means dulling the blade a bit. Different strokes I suppose.

I'd like to be in on whatever tests you formulate, we can compare notes.

Just some notes on garnets and natural stones.
The garnets in a sedimentary stone have been sorted by a natural process. Water or wind.
As such there has been a sorting action.
There are several types of garnet and depending on where and how they form they will have certain characterisitcs. They did not form in the coticle.
Depending on their original rock type that hosted them the sedimentary rocks derived from the original garnet host will have a base colour tinged with the colour of the garnets -pink, brown, to deep red or even black.
The garnet count will have a bearing on the colour of the natural rock.
Keep in mind that the garnets in the natural rock will be from a maximum size as determined by the energy of the process that layed down the sediments that they are trapped in but there will be a whole bunch of finer garnets there too. So to say for instance that the grit or garnets are of a 12,000 mesh for instance is a bit misleading. In fact you may have a maximum size of 12,000 mesh but also you will have garnets ranging from that all the way to 30,000 or beyond.
Garnets are heavy so they tend to be concentrated in sedimentary processes. Finding a sedimentary rock that carries not only the size but the concentration is the trick.
I have never tried the lather but would suspect that lather would hold garnets in suspension better than plain water and what that means I dont have a clue.
As a further observation the nature of the sharpening is likely different than from a man made becasue in most man made systems the tolerances are way tighter on the maximum/minimum tolerances for grit sizes.
So here is a question - would the wide range of garnet sizes found in a coticle be in a way duplicating a honing pyramid? Like having a 4000 grit stone honing with an 8000 grit stone followup . Not the best way of putting it but I hope you get my drift. The mixed grit would have both an aggressive and a polishing naure at the same time.
Hmmmmm.....

You got me on the garnet content. Still, 35 percent means a lot of the slurry isn't garnet.

We've had the discussion about different garnet sizes before, but I can't seem to find the thread. I don't think the crystals are the same size. Try honing on a Belgian blue without a slurry, and do the same with a coticule. The Belgian blue edge will shave differently. It's a nice, smooth edge but no where near as sharp as the coticule edge. Garnet concentration couldn't account for that.

Josh

I just got the info from that Belgian stone resource page, and they seemed to think the garnet crystals could be given a label of 15 micron with out much worry of variation, so that what I was basing my analysis off of. Whether it is entirely correct or not, I don't know.

And what I meant by garnet concentration is this; if you consider the surface of a piece of metal to be uniformly flat, and the surface of a stone to be flat and uniformly covered with garnet crystal sticking ever so slightly above the binder clay (or more realistically, the clay moves out of the way exposing garnet) with the appropriate percentages of each, then the lower the percentage of garnet means that the same amount of force acting down from the razor would be distributed over fewer garnet "peaks" and thus increasing the pressure at each contact point (since the area that is garnet has decreased relative to that of the razor). And a higher pressure on each garnet facet in contact would mean deeper more ragged cuts. Same principle of the bed of nails, lay on one nail and you're a kabob, lay on a couple hundred and it is uncomfortable but you do not get skewered.

It is the same reason many people say honing wedges or 1/4 hollows with wide bevels takes longer, it's because there is a larger surface area to distribute the weight of the razor and that means less abrasion per stroke.

Though there are sundry other variables and possibly a difference in actual garnet size, this is the way that I rationalize what is going on based on the info that I found on a quick search. I'll look for more and refine anything that may need it.

Russel,

Just for the record, I'm not trying to antagonize you. Your posts are well thought out, and I'd be willing to bet that you have more overall sharpening experience than me. Belgian hones are just my thing; I've experimented a lot with them, and I really like them.

I can see what you're describing, and I think it's entirely possible. I have always assumed a different size and shape for the garnets, but I don't have anything to point to other than my interpretation of what the hones were doing, based on my different trials.

I'll have to see if I can dig up the other discussion I mentioned and see if there was an authoritative source involved, or if we were just BSing.

Josh

Originally Posted by JoshEarl

I can see what you're describing, and I think it's entirely possible. I have always assumed a different size and shape for the garnets, but I don't have anything to point to other than my interpretation of what the hones were doing, based on my different trials.

Josh,

We're all buddies here, no need to be shy about standing your ground. Your observations are well developed, and backed by loads of experience (surely more than mine in pure razor honing), my point is just to interject my own experiences and "expertise" on the subject so that we can both arrive at a higher level of understanding.

The argument about pressure distribution is one that's universal for any two objects in contact, exactly how much it relates to honing, though, would depend on the size and shape of the garnets, which I assumed to be fairly consistent. If they are not, the argument decreases a little bit in validity.

Also, aside from the above arguments which are mainly razor related, there has been a significant amount of research done on this subject (for general cutting edges) by a man named John Juranitch. He did extensive testing, mostly for the meat packing industry (those guys slice through hundred of pounds of cold meat daily, and use every trick there is to get maximum sharpness and edge retention possible), on what kind of stones give what kind of edges and how those results vary with the use of water, slurry and oil. His conclusion was that with almost every type of stone, using it dry put the finest edge on the utensil. His testing included microscopic examination as well as field testing to be sure of the results.

So with all of the above in my mind (personal results, visual conformation, and outside concurrence) I stated that the dry stone should outperform a wet one. BUT, as we have said, there may be small variables that alter this reality for the coticule, but how much is yet to be determined.

In addition, the smoothness of the edge "should" go along with the fineness as both are determined by grit size and aggression of cutting media, but since we are dealing with the same cutting media, the method that achieves the finest edge "should" produce the smoothest one as well (in terms of actual smoothness of the steel). I think the point where we differ is that it's personal preference for how fine the edge should be.

So, maybe we can formulate an amended rule of thumb: if you like the edge off of an 8k, try the coticule wet for a fine, smooth edge. If you lean toward .25 diamond, try it dry to get that extra bit of sharpness. Does that resolve the difference, maybe?