Steve Voigt
Derek, I understand your point in response to Bill, but I think you're oversimplifying. The purpose of the pure chrome ox (.5 or .3) is not to get a sharper edge than the formax stick, at least not in the way I intend to use it (and it sounds like Dave has used it this way too). The purpose is to knock off the bits of wire edge a little more easily/quickly than a bare leather strop would. I use a bare strop and it works fine, but I'm interested in an experiment, nothing more, to see if I could speed things up a tad.
This is probably only relevant to oil stone users anyway. A fine Ark will leave a wire edge that must be removed. With your water stones, the slurry beats up the burr enough that there's likely not much wire left after your 10K stone; in fact, I'm not sure I see the benefit of the green strop after a 10K stone, but I'm not a waterstone guy so I'll leave it alone.
Broadly speaking, there are two fundamentally different activities that get described as stropping (you've written about this before and we're in complete agreement). Stropping on plain leather is about removing the wire edge remnants after an oil stone, and done correctly will have no effect on the geometry established by the stone that preceded it.
On the other hand, scribbling green stick on mdf or leather and using it aggressively is really just adding a finer "stone" to one's repertoire, a "stone" that's more flexible than a real stone. Nothing wrong with that, but it's a different thing.
The 0.3 powder is interesting to me because it's potentially a liminal instance, abrasive enough to knock off that oilstone burr without being abrasive enough to establish a new geometry or raise a new, finer wire edge.
Personally, I could care less whether the fine powder is al ox or chrom ox. I suspect the chrome ox is less aggressive and would work better for me, but I don't really know that. I have no idea where Bill is going with this comparison, whether it's intended to solve an actual problem or is just theoretical speculation.
Side note on your Sellers comment: I think he spends 5 minutes on the "strop" for two reasons: (1) the diamond stones he uses are so harsh that he's got to at least ameliorate the deep scratches they leave; (2) his technique makes for pretty haphazard geometry (and I'm sure it's even worse for his acolytes), so he's got to make sure he actually "strops" all the way to the edge, through brute force and repetition.
OK, I'm done ranting.