FIFTY Micron Chromium Oxide or..I shaved off of a 300 grit edge this A.M.
There was a recent discussion regarding particle size of Chromium Oxide going on. As a result which sparked a renewed interest for me to search for Chrome Ox in particle size of more than .5 micron I ordered a 100 gram container of German made Chrome Oxide Green 17 or "Veridian" from HERE
Both the website and a prompt response to an email I sent to them stated that the particle size of the pigments they sell are 50 MICRON.
When received, I saw it was what I would consider to be identical in color to the "Hand American" remarketed .5 micron chrome ox. I rubbed a little into a sheet of copy paper at work and gave my pocket knife blade some passes over this powder. It promptly removed bevel scratches and created a mirror finish and a sharper edge.
When I got home I put on a disposable nitrile glove and mixed some up with some Norton Honing oil into a green paint. It behaved identically to the "Hand American" chrome ox when it's mixed with the oil EXCEPT I felt a hard grain of something on my gloved fingertip. One grain quite a bit smaller than a grain of sand or table salt. I removed the grain from the mix easily and didn't feel any other grit of any kind. Only smooth "paint". I rubbed this paint right over the balsa pieces I've used for over a year which I originally pasted with .5 chrome ox/oil and have kept in my medicine cabinet for effective touch ups when needed.
I grabbed a new TI Super Gnome which I honed previously to shaving sharp from factory edge and did a large number of passes to "seat" the chrome ox paint into the balsa. I wasn't concerned about creating a wire edge. 100 passes. I wiped off the excess chrome ox "paint" and inspected the edge under light. There was a broken barely perceptable white line glint at the edge. It most likely was a wire edge. I drew the edge (weight of the blade only) perpendicularly over the edge of the balsa twice, did a few more passes on the chrome ox and...no more edge glint.
I stropped this up with fifty passes on my plain horsehide strop. The edge was popping hairs above arm level nicely and passed the HHT with no problems. Since I wasn't going to shave last night, I couldn't resist soaping up the back of one of my hands and did a pass. With the cushion of the soap, I could NOT feel the razor wiping the hairs off the back of my hand. I couldn't wait to shave this morning!
The shave: I shaved completely without irritation. The edge was NOT a .5 micron edge clearly. However, what would otherwise be unthinkable to me (shaving off an approximate equivalent 300 grit edge) was a passable and successful shave all around. For my taste, I would not consider this edge as "shaving sharp" although obviously it was a shavable edge. The edge was noticeably more "grabby" but not harshly so. I do not envision being able to do a complete shave off of a 220 or 500 grit stone; I've never done that, but I would think I would find the edge too harsh. What does this reinforce?
- HHT is not a "tell all" test and the only test that is is the........everyone!....."The Shave Test!"
- Particle size as I and others have said before is only half the equation. Particle shape, hardness, etc is equally important. The rounded chrome ox particles vs. a sharp shardlike diamond particle can cut "coarsely" but can give the "comfort" to an edge even at lower grits.
- This powder looks like it could be used successfully to smooth out bevel scratches on say a DMT 1200 grit plate before moving up in grits should one desire such a result. What, approx 300 grit removing scratches from a 1200 grit plate? Rather than remove them, I believe the round chrome ox particles round scratches rendering them visibly unnoticeable.
- I'll bring this to the MN meet divided into small packets and give a packet to anyone who wants to play with this stuff. I don't have a ton of it so I'll limit the offers to actual MN attendees.
Yup, I shaved off a 300 grit edge this morning (unless that company is wrong in their particle sized info. Even if they are, I can say with certaintly based on my experience that this powder is significatly coarser than .5 micron.).
Chris L
