Chromium Oxide and overhoning?

It's clear with those of us that use Chromium Oxide to polish edges on paddle or hanging strops that a little goes a long way and not many passes are needed to do the job.

Most recently, I applied some .5 micron Chromium Oxide powder to some newspaper (think the diameter of a pencil eraser and blotting, not a quantity the volume of the eraser, just a flat circle of chrome ox the diameter of the eraser. I spread it around a bit on the paper....that was more than enough. The edge was already pretty polished off a silky Thuringian. After less than 20 passes on the chromed newspaper and the strong stinging smell of steel, the bevel under 40x magnification was absolutely mirror smooth save for a few isolated deeper striations from the lower grit process.

Now for my question: I've heard it said that you can overhone or even form a wire edge on chromium pasted strops. I have not purposely gone to excess with chrome to try that out but....with .5 micron chromium, why or how could overhoning happen? The stone equivalent would be the Shapton 30,000 grit ceramic on glass. Dr. Chris Moss told me that in his experience with that stone if light pressure was applied during honing on the 30K, he thought it unlikely or more likely close to impossible to overhone on that stone.

Any thoughts on this? I think I'm going to try to overhone on purpose with chrome ox much like HeavyDuty did with the yellow coticule and see what happens.

Chris L

I have tried 100+ passes on a pasted balsa strop. Still shaved well, and the edge is still holding up after 5 shaves or so. It was on a Wostenholm and Sons.:shrug:

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Originally Posted by joke1176

I have tried 100+ passes on a pasted balsa strop. Still shaved well, and the edge is still holding up after 5 shaves or so. It was on a Wostenholm and Sons.:shrug:

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Cool, thanks for the info, that's what I'm looking for. The other thing I'm wondering that might be at play: since there are two general categories for edge prep prior to chrome ox (hones vs. pastes), maybe a razor honed on stones and finished with chrome ox exhibits different edge endurance than an edge honed with pastes and finished with chrome ox? Other than chrome ox, I've never used pastes but some have said it can turn the edges into paste junkies needing a refresher fix more often than a stone honed edge.

Chris L

Its still an abrasive and if its an abrasive you can overdo it. Remember the Grand Canyon was formed by abrasive action of running water.

Also by the time you use the Cr0 the edge is pretty much at its best so what your looking for is that final polish. if you do too much even being very fine it may just push that very thin edge into a state where it just is too delicate and doesn't hold up well.

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Originally Posted by thebigspendur

Its still an abrasive and if its an abrasive you can overdo it. Remember the Grand Canyon was formed by abrasive action of running water.

Also by the time you use the Cr0 the edge is pretty much at its best so what your looking for is that final polish. if you do too much even being very fine it may just push that very thin edge into a state where it just is too delicate and doesn't hold up well.

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It's an exciting mystery for sure how HeavyDuty could literally do one thousand passes on his yellow coticule with no ill effects to the edge of his razor. :shrug: Anyway, I'm going to be strop strop stropping on some chrome impregnated newspaper, I'm thinking 100 passes at a time with shave tests in between to see what happens.

Chris L

I haven't found wire edges to be a problem with chromium oxide. Most of my experiments have been with lightly pasted hanging strops, and I've done 50 to several hundred laps with no apparent problems. I've also done up to 50 laps on a lightly pasted paddle strop with no problems.

Now I have killed edges by using a strop with too much paste on it. I think that's a more common issue. And I've developed wicked wire edges on diamond pastes, which is why I quit using them.

This sounds like a worthwhile experiment. :)

Josh

I remember a couple of times when I "thought" I developed a wire edge on the chromium strop, but this is rare. Most of the time, it polishes up the Norton honed edge without any problems. But, even if the green did overhone it, the remedy would be simple; go back to the hone for a couple passes, then hit the green again more cautious this time. In other words, don't worry about it too much.

I think on any diamond pasted strop, less is more. Diamond crystals are much more angular for any given grit size, hence tend to be faster perhaps and more agressive.

Coticule have more rounded crystals as do Arkansas stones I hear so may leave a smoother edeg even is many, many passes are taken.

Tony

It certainly is a worthwhile experiment, but I am puzzled about something. I've yet to see my first overhoned edge (probably due to the fact I'm a coticule adept), but I 'm lead to believe that an overhoned edge can be wiped away by what is referred to as "backhoning". Isn't stropping the same as backhoning? So how could something that resolves overhoning, cause it at the same time?
This is by no means meant to sound skeptical, but I'm ever so interested in the raw physics behind our observations.

On another note: I have been stropping razors on a paddle strop, loaded with a thick, gunky layer of chromium oxide. I overpasted by accident, and decided to experiment a little first, before I wiped the excess off. Of course Josh Earl was right: it does dull razors in a rather few laps. (It' so nice to learn things the hard way :hmmm:) The more laps I did, the more it dulled the razor, even to the point that I ended up with such a nicely rounded edge, that I had to put it to the DMT-E to restore the bevel. I kept a close watch to what happened under the microscope. (Sorry for the poor picture: my scope doesn't have a picture tube, so I shot it with a regular digital camera through one of the eye-pieces)

You can clearly see how the chromium oxide polished, but also rounded the outer part of the cutting bevel.

It is my theoretical expectation that you will experience the same, only, it will take you much longer, because your thin-pasted strop is cutting slower than my heavy-pasted one was.

I'm looking forward to the findings of your field experiments.

Kind regards,
Bart.

[quote=JoshEarl;204165]I haven't found wire edges to be a problem with chromium oxide. Most of my experiments have been with lightly pasted hanging strops, and I've done 50 to several hundred laps with no apparent problems. I've also done up to 50 laps on a lightly pasted paddle strop with no problems.

Now I have killed edges by using a strop with too much paste on it. I think that's a more common issue. And I've developed wicked wire edges on diamond pastes, which is why I quit using them.


Thanks, Josh (it seems to me that I seem to be thanking you a lot these days)

I really needed to hear that. I was in fear that I had, perhaps, over honed my entire herd with my new Chromium Oxide pasted linen strop (40 laps each). :D

Steve