ESK/Ceradyne Tetrabor 3000F - first impression

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Nov 16, 2002
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Got some of that 0.7 micron boron carbide ceramic powder the other day. Sent some to QuietOneD, Steeldriver, and BillL as they were curious to how it'd work and they chipped in. Finally put it on two strops tonight.

First off:

A little goes a long way. I wouldn't be surprized if there's more abrasive in a half-teaspoon of that stuff (which is entirely abrasive and you must mix with the goop of your choice) than in a 5 gram syringe of diamond paste. With three pinches, I've totally saturated two strops and made a mess on the work table.

Secondly:

It readily mixes with mineral oil to form a sludgy paste that will evenly coat anything. Might even put it on the cat's tail to keep from having to go down to the basement if she wakes me up for turkey tonight.

Third:

I don't know. On the small strop, it put a brilliant edge on a Spyderco brand Dodo folding pocket knife that was already fairly sharp. On the wide strop, it turned the coarse-edged but massively sharp Victorinox Tinker into a smooth-edged but massively sharp knife. Nice, but that can be done with most every abrasive.

Will strop more knives with S30V as they dull and report back. So far, not enough data to be impressed, but the promise is there.
 
It would be interesting to see if it behaves any differently from CrO on 1095 vs M2 (or similar) as the real ability is the inherently much higher hardness of the abrasive. It would also be informative to see how it reacts to burr removal vs CrO as I noted that this is problematic on stainless.

-Cliff
 
I'm wondering if there is an optimum solution? Ie. 2 to 1 mineral oil and boron carbide or what?

When it arrives I think I'll try for thick and thin out from there and see what it does as it gets thinner.

I've used the coarser boron carbide from Hand American and it was quick on HARD D-2. It was coarse, listed at 1.8 Microns but I swear was more, least it acted like it. Gave a hell of a shine though, scratch pattern was fine enough really. But then PSA 1 micron tapes came along and most knifes aren't that hard either.

Going to be interesting.
 
BillL,

Anything that will hold the boron carbide in place is the goop. Mineral oil, wax, shortening, water, corn syrup, or even letting it embed itself into a thin film of plastic.

Cliff,

Sometimes, I oversharpen my U2 and it gets an annoying burr. Will report back on how it deals with such a burr.

QuietOneD,

The powder mixes so well with mineral oil that a 2:1 combination may be too much powder. If the USPS folks can be believed, you'll be able to find out in about a week.
 
Ok...

1. A little boron carbide goes a long ways. Repeat after me... A ..... L O N G ways.

2. A pencil lead size drop of powder on the bosses kitchen counter top can spread amazingly far. Keep gel waterless hand cleaner and paper towels handy.

3. I made a slurry/paste of 1/4 of 1/4 teaspoon and mineral oil to form the muck. It barely moves when held at an angle. I put 3 large drops on 2 different strops. 8x3 each. Rubbed in let sit then wiped off with a linen rag to the point was little coming off on the rag.

3. I tried it out on two very different knives. D2 necropsy knife. This knife is the second hardest blade I have. Short blade 1.5 inches width at heel is 1 inch. 3/16 thick at the spine. Blade shape is a triangle to a fine point, blade side is flat grind. Flat spine. Has been heat hardened, tempered and has had 3 stage cryo treatment. This is a HARD knife with a very fine grain structure for D2. (mulit cryo effect??). Sharpen on EdgePro, touch up with 15K Shapton, then 3000 grit polish tape. Then strop on the boron carbide. This is now membrane seperating sharp. This is the fastest I have ever gotten this knife sharp. 15 passes on the loaded strop. This is as close to scapel sharp as I've ever gotten it. I'm happy for this alone.

3. 440C 10 inch fillet knife. This is a hard 440C cryotreated after purchase and new scales put on. Knife was sharpened to 1000 grit polish tape but not stropped the day before. 10 strokes per side and it was WHOA sharp. I didn't go any further.

4. One strop I left loaded and will see how long it lasts. The other I cleaned up with gel waterless hand clearner and rags and paper towel. Clean up to almost new condition. Cleaning hands, strop or counter tops with the hand gel cleaner is a breeze. Keep it handy.

Need to find how to best apply the boron carbide. How much. I'll try a camera lens cleaner, put a bit in the squeeze bulb and spray then spread with the fine brush. Then rub in with fingers. Will also try thinning out the present concentration to differenet levels. I know it is too high on boron at this point.

The necropsy knife can be a bear if I make a burr at any point. It had a minor wire when I started stropping but it vanished in very short order.

Conclusion IMPRESSED.

But there is a lot more to try and learn and initial efforts may not hold up with other blades.
 
I now suspect why those crazy people at Hand American say to very barely coat a strop with stropping stuff:

The abrasive particles, if on top of other abrasive particles and binding agents, seem more likely to slide around than if they're between a strop and the blade. Haven't done a third of the research QuietOned's done, but I've made more of a mess. And with barely any powder. :o
 
Took off a lot of excess with alcohol hand cleaner and tried again. Got better results on my Yojimbo (with Wilsonized semi-hawkbill blade). Before that, my Benchmade 921 Switchback (also Wilsonized and ground thin) and Spyderco Dodo (factory heat-treat and geometry) got sharp with the boron carbide quicker than when stropping with CrO/AO. About the same speed as 0.5 micron diamond paste, but much less expensive. About the same cost as 0.5 micron Aluminum oxide (okay, less, but four of bought in bulk), but is a harder compound per the Mohs scale (9.5 vs. 9).
 
Cliff Stamp said:
Any comparisons to the chromium oxide compounds?

-Cliff
Well this is preliminary on a very few blades. 1. It's faster on HARD D2 and M2 than anything I've encountered in silicone or aluminium carbide. I don't have a diamond compound to compare it to. As my diamond paste is much smaller. 2. It cuts feathers/wires off soft 1095 like a chain saw through butter. 3. Works great on cryo treated 440C 4. A little goes a hellish long way. In my very limited use so far it's about 3 to 4 times as fast as CrO2 in 0.5 micron size. Blade finish does seem smoother to touch and under 20X magnification than CR02 on finished blades. Grain shape of the boron? I had a go at my custom M2 and it is the hardest blade I have or that I've ever worked with. This is the knife that files skid off and only scuff. Can actually wear a file out before you do anything significant to the knife. While honing with silicone or alumina on this does work you have to be very patient. Boron it was like... well like what stropping should be. 10-12 passes and it was done. This is no pressure but what is required to control the blade. Softer blades actually seem better if that makes any sense. Wire edges or minor burrs just seem to go away after a few strokes. These aren't major burrs mind you, just vesitages and minor wire edges. Much faster than silicone or aluminum carbide at 0.5 The boron is large but I don't think the larger grit is enough to account for all of the difference. I'm impressed so far. (Sorry paragraph breaks are not working.)
 
Tried reprofiling and sharpening a Manix on my Norton 1000/8000 waterstone. It wore away part of my left middle-finger, but I stopped before getting the edge even hair-popping sharp. Not a place to stop and change grits. Shouldn't have left 1000 grit before that was achieved, but I did any ways.

Hey, there's a strop loaded with boron carbide right near my flesh-eating jackolacking waterstone! Huckabucka alternating passes later and my left arm has tons of bare spots. This is very cool because doing the same feat with 0.5 micron CrO/AO has taken longer in the past. Here's a pic of the purdy edge left by gliding a knife along a boron-carbide loaded strop. Magnification at 200x:

boron_man1.jpg

You can kind of see a transition between where the 8000 grit waterstone stopped and the boron carbide took off.
 
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