Thread: Chromium Oxide paste

I frequenty experience exactly the same thing, Vern. I think you're on target.

X

Some guys can get this level of sharp on a hone. Lynn can for sure, the two blades I've gotten from lynn smoked my best results on a hone and nearly everything I've done on chrome oxide for that matter.

Chrome oxide makes a hero out of just about anybody, which is part of why it's so addictive, and partly why it's not necessarily a good thing to have available when you're first learning honing. It's a crutch - you can get a poorly honed razor shaving sharp with chrome oxide but you can get a well-honed razor spooky sharp on chrome oxide. It's easy to get complacent and get sloppy on the hones, because the chrome oxide will get it sharp anyway. I occasionally go through periods where I stop using the paddles and try and match that level of edge using just the hones, and sometimes I get pretty close.

MParker,

I know this is hard to do, but could you elaborate a bit on how you judge sharpness? Do you bother with the HHT? What do you look for in a "successful" shave test?

I'm able to get edges that pass the HHT very well off the 8K, and they shave me pretty well. But my beard is tough, and I find that I can't get an irritation-free shave on my chin unless I go to .5 micron diamond paste on a leather paddle for at least 20 to 30 laps.

I think there's more sharpness to squeeze out of the Norton 8K, and I'm still improving. Can you shave straight off the Norton without any irritation?

I identify with what you're saying about getting lazy with the hones, and I hope to continue my improvement in that area.

Josh

I'm not the best guy to ask about this. But I don't use the HHT - the hair on my head is very very fine and even the feather won't pass the HHT with it. I use my arm hair, I just touch the hairs a millimeter or so above the skin and see if they pop. I use the hair on the inside of my arm because it seems to correlate better with the level of sharpness I want. I also use the thumb pad test. But ultimately the shave test is the important one. I've got a pretty tough beard and get noticeable pulling even with the feather AC, so that's really where I see how sharp the blade really is. Shaving with the grain isn't too critical pull-wise, the only thing I'm looking for here is how much stubble is left. The real test is across the grain on my chin (toughest hair, and toughest part to shave in general), and against the grain under my jaw.

I should also mention that I'm using the armhair test less and less because I'm getting better at feeling the fin forming up on the hones. I can't feel this on the norton, which is one reason I don't use it much anymore, but the arkansas stones, tam o shanter, and shaptons really tell you a lot about the edge, especially if you're honing a smiling blade where you can easily feel what's happening at each point along the edge as you rock the blade down the hone.

Yes, I can shave off the 8k without irritation, I've done this off and on since I started depending on what else I was playing with. But I get more pulling than if I finish on the 8k shapton, which is more pulling than I get if I finish on the 15k shapton, which is more pulling than if I finish on my "The King" barber hone, which is more pulling than I get if I finish on the chrome oxide. Even so, low "pulling" or "tugging" isn't the only quality I'm looking for in an edge - toughness and smoothness are others, and IMO sharpness and smoothness aren't quite the same thing (vis the feather). My fondness for Cr2O3 (and Boron Carbide) is because they combine smoothness, sharpness, and toughness (when used on a hard paddle, though this comes at the expense of honing speed). Diamond is very fast and is available in some impressively fine grits, but tends to leave a rougher edge and IMO seems to produce a less stable edge at similar grits.

I have been comparing Aluminium oxide lapping films with CrO and find CrO gives a much better finish.

For clarity;

Dichromium Trioxide (Cr2O3), commonly called Chromium Oxide, Chrome Oxide and sometimes Chromic oxide is, I believe, the is the substance we are using.

Chromium Dioxide (CrO2) which is also sometimes referred to as Chromium Oxide, is a magnetic substance used to make audio cassettes.

I suppose we could write it in short form as CrO, but CrO2 is just the wrong stuff.

X

Originally Posted by mparker762

It's easy to get complacent and get sloppy on the hones, because the chrome oxide will get it sharp anyway. I occasionally go through periods where I stop using the paddles and try and match that level of edge using just the hones, and sometimes I get pretty close.

This is one thing I still don't 100% get. Is the poorly honed razor that's nevertheless sharp because of chrome oxide inferior to one well-honed on stones? I've always assumed that's the case from the way people talk, but I've never really understood the physics of it.

Originally Posted by mparker762

My fondness for Cr2O3 (and Boron Carbide) is because they combine smoothness, sharpness, and toughness (when used on a hard paddle, though this comes at the expense of honing speed).

If used on firm leather, the edge is inferior?

Originally Posted by dylandog

This is one thing I still don't 100% get. Is the poorly honed razor that's nevertheless sharp because of chrome oxide inferior to one well-honed on stones? I've always assumed that's the case from the way people talk, but I've never really understood the physics of it.

That's been the case for me. It's like the paddles can improve an edge X amount, and this can get a marginal edge into the "good shave" levels of sharpness. But you're much better off taking a razor that's already shaving sharp and giving it that same X amount of improvement. But it's very easy to become complacent and be satisfied with the first route.

Originally Posted by dylandog

If used on firm leather, the edge is inferior?

I get pretty consistently better edges on hardwood than leather, though the difference is probably modest if you use a very smooth gentle stroke - I have trouble achieving this to my satisfaction on leather because of the drag. IMO the wood surfaces are much more tolerant of pressure and much less prone to weakening the fin, and because the drag is so low it's much easier to maintain a very light touch and smooth stroke. However, pastes on hardwood are much slower than pastes on leather, so it's not an unqualified win by any means.

Originally Posted by mparker762

I get pretty consistently better edges on hardwood than leather, though the difference is probably modest if you use a very smooth gentle stroke - I have trouble achieving this to my satisfaction on leather because of the drag. IMO the wood surfaces are much more tolerant of pressure and much less prone to weakening the fin, and because the drag is so low it's much easier to maintain a very light touch and smooth stroke. However, pastes on hardwood are much slower than pastes on leather, so it's not an unqualified win by any means.

That's interesting to hear. I feel like I've been struggling a little with using my paste on a brushed leather surface. Maybe I should make a change.

X

Originally Posted by mparker762

IMO the wood surfaces are much more tolerant of pressure and much less prone to weakening the fin, and because the drag is so low it's much easier to maintain a very light touch and smooth stroke.

My chrome oxide/boron carbide leather bench hone just arrived today. I suppose I'll make a special effort to go gentle.