What's up with this 0.25 diamond spray

N

nuggetz

Joined
Jul 25, 2013
Messages
39
I finally picked up some diamond spray after struggling with the crappy sticks of compound I had laying around and I'm not sure what the heck is going on. I purchased some hand american boron 1 micron paste (the black stuff) and a bottle of 0.25 diamond spray. The black diamond paste works extremely well. I took a lansky sharpener to my buck knife all the way from coarse to extra fine and then stropped the knife on the 1 micron paste. Edge was really nice. I then went to finish things up with the 0.25 spray and after I was done stropping I couldn't cut a piece of paper. I'm not sure if this spray is putting a microscopic burr on my knife or if I'm dulling the edge. So far I've tried the spray on smooth leather, balsa, rough leather and even paper on glass and each time it takes the nice paper slicing edge that I get from the boron paste and turns it into a paper tearing edge. What am I doing wrong here? I know I skipped a grit since there's some .5 micron spray but you would think that at the very least the edge would remain the same if 0.25 is too small. This stuff is pretty useless to me. I should have followed my gut and went with the 1 micron but I chose the 1 micron boron paste instead since it was more expensive and had terrific reviews.
 
You might be rounding the edge off. I might notice the edge not getting any sharper, but I've never had an edge get more dull.

Of course, I have the DuPont 0.25 micron diamond spray and I use it on a belt sander, so YMMV;).
 
Well I can't say that its dull per say, it just doesn't slice paper. I'm sure it would slice a tomato. Maybe I got a bunk bottle?
 
Diamond/CBN may be a little overkill for the Buck knife (I'm assuming 420HC). Not that it can't work (it can), but it's easy to over-polish with diamond on low-wear steels, even at very small grit. Combined with stropping on a softish substrate like leather, it's very easy to round off and remove any 'teeth' that might've been there before. If your blade is 420HC, try SiC (silicon carbide), alumimum oxide or green compound instead (green is especially good on this steel, straight off the hones). These will still polish, but they go about it a bit more gently, with less risk of overdoing it.


David
 
I doubt you got a bunk bottle. The QC in the HA sprays is top notch. Surpassed only by Ken Schwartz' stuff. There is something else going on here and I suspect it has something to do with technique. Boron Carbide is much more forgiving compared to diamond (even the monocrystalline diamond in the HA sprays)

How do you establish what angle to strop at , or do you just go with what "feels right". Precision when using this compound will make or break it. It will produce amazing results quickly. But it can just as quickly cut off an apex. And I strongly suspect that that is what is going on here.
 
I had the same problem when I first started using finer compounds.

My trouble was technique. I was rounding the edge. A slight adjustment to technique solved the problem.
I also agree with the posters above that diamond is a bit of overkill for the soft 420HC steel Buck uses.
 
I really think that its putting a burr on the knife. I know my angle is good. I start with the tip and I can feel the bevel as I work my way to the bottom of the blade. I do a bit of hand sharpening on my Spyderco combination ceramic stone first and the edge is perfect so I know my angles are pretty good.

Last night I tried to figure out what was going on and did some heavy duty stropping on the diamond spray and switched immediately to an untreated leather surface (smooth side) and I could feel the burr dragging across the leather. I never felt that before. Took some doing to knock it off by stropping on the plain leather. I think this stuff cuts like crazy. I might need to experiment with fewer strokes and yeah, I think my Buck steel is too soft and the diamonds are eating it for lunch. Don't really have anything harder to test on. Def going to get some of the chromium oxide stuff. At least that will probably be better for the buck knives after using the black paste.
 
Ken sells aluminum oxide , up in that size rating. More consistent particle size than other Alox products out there. The only chromium oxide I would touch would be the Hand American stuff sold at CKTG.
 
Sadden said:
Ken sells aluminum oxide , up in that size rating. More consistent particle size than other Alox products out there. The only chromium oxide I would touch would be the Hand American stuff sold at CKTG.
Click to expand...



My experience tends to agree. HandAmerican CrOx is consistent. VERY consistent.

But don't try it on the so-called "super steels" of you'll be stropping all day.
 
It's not a burr its a 100,000 grit. One small mistake of pressure or angle and you round the edge. It's also far too fine and such a compound is best on very hard steels.
 
I wasn't all that impressed with the 1/4 micron spray. It doesn't make my knives any sharper it just makes the edges prettier. I power strop on my belt grinder with flitz in a leather belt and it makes my knives insanely sharp. The diamond spray just pretties them up.
 
I think the main culprit is the steel. What I found several times the hard way is when that edge turns to crap is that the steel simply won't take the extra refinement at the angle being sharpened. If you want to go up to these high level finishes, try doing it at a more obtuse angle - even if you do it with a microbevel. It isn't the Boron Carbide or diamond or CRO or ALOX. Any of these will cut soft steel.

Having said that, don't expect an ultra-refined edge to last long on a soft steel blade like a Buck.

" did some heavy duty stropping on the diamond spray" What does this mean - heavy pressure multiple strokes, etc? This may be a problem.

And of course I'm not excluding inconsistent technique, but even with good technique, some steels just don't perform at acute angles.

---
Ken
 
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