Well a few comments here on this post and some subsequent posts.
Regarding the medium or substrate that the compound is on:
I feel that leather does have it’s place as well as harder substrates. Of course the pressure applied makes a hugh difference here. Convexing an edge is both a measure of the substrate’s ‘give’ as well as angular consistency. So you have a range of substrates going from softest to hardest for example:
Thick neoprene / mouse pads
Thinner neoprene - various thicknesses found at dive shops - thinner has less give generally
Cardboard from corrugated to thin cardboard to card stock or index cards. This continues to various papers which can themselves be supported by various media (the substrate’s substrate).
Leather. Not all leather is the same - at all. So soft thick cowhide has much more give than thin Kangaroo hide. Here the surface characteristics also come into play. The edges I get from Kangaroo that is about the thickness of index cards allows for less convexing OR more pressure or somewhere inbetween - ie technique differences.
Woods. Various woods have different amount of give. Depending on the compound and grit sizes some are more ideal than others. I find that a slightly softer wood like Balsa is ideal for many things because the slight bit of give lets the particles stay in place a bit better. Too hard and the particles roll around. Harder woods like Baltic Birch do give a good flat surface, but particles slide around a bit too easily for my tastes. This is similar logic to using a soft steel platen to help the particles stick rather than just roll off on a harder steel surface. Of course different woods will have different abrasive properties themselves.
Paper. Revisiting this separately, paper can give one of the harder surfaces over glass, similar to films. Paper qualities become more critical at the finer grits as one competes with the clay abrasives that are a common contaminant of the paper manufacturing process, to say nothing of the abrasive qualities of the wood pulp in paper. Cotton and sugar cane pulps can give a finer finish in many instances, with cotton typically thicker stock and bagasse or cane pulp yielding very thin paper. My preference for paper with finer compounds is Rhodia or Clairfontaine. For coarser grits, just plain copy paper suffices.
Nanocloth - here you have the extreme of a neutral substrate, giving an absolute minimum of abrasiveness, allowing a pure effect from the compound applied.
Now angle control also produces convexity. So if you can control this, then the ‘give’ of the substrate is more worth consideration - like the control a WE affords.
Compounds can be put directly on film or be stuck to them as part of the manufacturing process. Like sharpening belts, there are various film substrates with specific qualities.
Waterstones - You can use various compounds on the surface of stones. This, depending on the stone gives a fairly hard surface to work with easily flattened to maintain precise flatness.
We have a similar issue with grits. Finer grits are best appreciated when other variables are controlled.
While we don’t have or need the luxury of a level five clean room, a few things will give us adequate control. KEEP strops with finer compounds in their own ziploc baggies. An uncontaminated ziploc gives you all the control of contaminants you need in a practical sense. When you aren’t using them, keep them there to reduce airborne contaminants.
There is no need whatsoever to associate what you can see in terms of finish with that being your rate limiting level of finish. You will get a mirror finish with a 5k Shapton, but certainly you can go past that in terms of sharpness. Indeed many cheap compounds do. But the biggest problem with cheap compounds is their inconsistency. You see this in particle size distribution data. You also have an issue of particle hardness with some particles eg iron oxide vs diamond or CBN. To say that a cheap supposedly 0.5 micron chromium oxide particle doesn’t require a clean room but a 0.25 particle does just doesn’t make a lot of sense.
And then there are natural stones. Here you have a hardness level that has a complex distribution and a particle size distribution equally complex with particle sizes varying during use as the mud refines, producing a more complex edge which has less of a single point of failure.
Here too you can separate the abrasive from the substrate by applying the mud produced from the stone to various substrates. Want a hakka stone that has little give? - put the mud on a hard surface (paper over glass). Want a soft version of say a Nakayama Asagi? - put it on a soft substrate like paper over neoprene. I often use balsa for these preparations. And of course you can blend natural stone slurries with CBN and diamond too for some superb effects.
Personally, I don’t think the price of a compound should be the chief concern. If a single spray of a concentrated compound of known formulation is used, the cost per sharpening is miniscule since a bottle will last SOOO long. What is more important is the value of your labor. I’m not saying this to be offensive, but having explored the realm of ultra refined small particle compounds, there truly is a difference in results best appreciated by trying it, as Clay mentions in his posting. There is sharp, there is sharper and there is even sharper. I thought I knew what sharp was, but I have proven myself wrong so many times that now I just look forward to reaching the next level.
Ken
[quote quote=“BassLakeDan” post=2374][quote quote=“KenSchwartz” post=2128][quote quote=“leomitch” post=733]Like any kind of stropping, aside from touching up the edge, it is also slowly convexing the edge. So eventually that bevel will change its shape to the convex shape we know and love. Nothing wrong with that! But if you want, it is but a few minutes work on the WEPS to get a nice sharp shoulder with the attendant bevel. Sweet!
Leo[/quote]
Well you could use the strop mounted on the paddle to freehand sharpen as well, but as LEO points out, stropping on the WEPS will give you greater precision and less rounding of the edge over time. Precision stropping is especially advantageous if you are using several levels of refinement (grits) stropping as opposed to just your final strop. Of course, the compounds you use for stropping on the WEPS can be applied to bench sized strops as well. And the cheap compounds could be used on the WEPS too (not that I would recommend that, but I’m biased 
)
Ken[/quote]
I did not realize that this thread was here on the forum, as I am a newbie to posting, and have limited understanding of how all this works. So long story short mistakenly I posted my thoughts about the above topics at:
http://www.wickededgeusa.com/index.php?option=com_kunena&func=view&catid=6&id=2304&limit=6&limitstart=6&Itemid=63 but will expand them here a bit..
Mentioned in my other post was my preference for non-leather strops and the use of cheap easy to obtain spanish cedar wood strips for a non compliant base material to hold strop compounds. I feel there is a strong case to be made for the abandonment of leather as the stropping material of choice. Now that you have a nice edge on your steel via the WEPS system, why should you convex it with a leather strop? It is the form compliant nature of leather that is causing the convexing, not the compound. I have been stropping blades for many years, experimented with all sorts of compounds and strops, and can say that (for me anyway..) the evil-doer of a bad strop is ( in order of issue..) : 1.) a compliant base material 2.) bad hand technique 3.) and running a distant third (if at all) is the compound itself.
For what is worth, I feel that in the world of knife sharpening, once you get past the level of any compound that is capable of mirroring the metal to the naked eye then you at the limit of what you can reasonably achieve for the purpose of knife sharpening. Discussions of 0.25 micron high purity CBN sprays and the like, are to me (sorry not trying to offend anyone) are more or less of an exercise in nonsense and probably frustration. It takes very specialized, and very expensive equipment to apply such abrasives in a productive way. If you are a technician in a Class 5 clean room, with the right equipment, and the task at hand is flattening the base for a space satellite sensor then yes maybe we should be talking sub micron abrasives.
So I say, go ahead and use “cheap compounds” … experiment, and have fun![/quote]