Functional Difference in Strop Media

Legacy Forum Archive stropping
1

Hey all, long time lurker/first time poster here.

I was wondering about stropping. I have a a Pro Pack 1 en route with the 1200/1600 stones.

I switched the regular leather strops for Kangaroo leather and upgraded to 1/.5 micron paste. Eventually, I’d like to have a set of Balsa and Nano cloth with different pastes and sprays per each.

Originally I had planned the 1/.5 on the Roo, .25/.125 on the Balsa, and .05/.025 on the Nano.

My question is along these lines: I figured the Nano cloth is best for the finest micron mixture because it has almost no traceable micron level while blank. Would the paste and sprays work as I have them listed, or should they be switched?

2

I guess the real question I’m trying to get at is the functional difference between certain media.

It’s seems obvious that Nano Cloth is good for sub micron grits because the media has no grit quality–unlike another media which might have an inherent grit quality very close to the minuscule micron sprays. But Nano Cloth, for the same reasons, would work GREAT with larger grit sizes. Why would one choose Roo over Nano? Why would I choose basic leather over Roo?

There is the small difference in toughness of the media resulting in convexing edges. But other than that, what’s the logic behind not buying all Nano-Cloth or all Roo and loading the different compounds on the same media?

The only other explanation I can think of is the progression of technology resulting in new products that stand beside existing products. Basic leather is trumped by balsa which is trumped by Roo which is trumped by Nano–but all are still sold together.

Thoughts?

3

It’s just a personal thing, but I’d prefer to finish with leather strops with no diamonds on it, just neatsfoot oil rubbed in, as the barbers used to use to strop their straight razors. The burnishing effect that leather has on a metal bevel is not replicated by any man-made synthetic substance. But I’m not necessarily suggesting that for you, as I haven’t used the nano cloth myself.

4

Right! That’s a good point. Forgot about burnishing. With just the Nano, all you’d get is a grit scratch pattern, whereas with Leather you’ll get the pattern plus the smearing of molecules. That probably explains why Clay’s microscope pictures of balsa vs leather favored the leather much more. Thanks!

5

You’ve asked some great questions. I’m sure some of the answer is cost… the regular leather is not as expensive. Plus, there’s a question of whether you’d benefit from using “coarser” abrasives on the nano cloth or 'Roo strops. One advantage you would have though is consistency. The 'Roo and nano cloths are thinner too, which means less chance of “rounding” the edge.

Don’t know what your goals are, but one thing to consider is going “too fine too soon”. You’ll improve the edge going to the 1/.5 pastes, but you probably won’t polish out the marks of the coarser stones or ceramics. Just thought I’d mention it… again, it depends on what you want.

Hope others chime in on some of this.

6

[quote quote=“cbwx34” post=10354]You’ve asked some great questions. I’m sure some of the answer is cost… the regular leather is not as expensive. Plus, there’s a question of whether you’d benefit from using “coarser” abrasives on the nano cloth or 'Roo strops. One advantage you would have though is consistency. The 'Roo and nano cloths are thinner too, which means less chance of “rounding” the edge.

Don’t know what your goals are, but one thing to consider is going “too fine too soon”. You’ll improve the edge going to the 1/.5 pastes, but you probably won’t polish out the marks of the coarser stones or ceramics. Just thought I’d mention it… again, it depends on what you want.

Hope others chime in on some of this.[/quote]

Thanks! I’m not too worried about cost. I’m going to take my time acquiring things.

My plan is to add Micro Ceramics and Chosera later on before I go all the way with the strops–I just want to get things straight in my head. I want to maintain as much of a V-edge as I can, so I’ll probably stick with Roo and Nano. Roo for the coarser stuff where the natural grit won’t have an affect and Nano for the crazy sprays.

7

Hello Jacob and Samuel,
I just wanted to point something out. Burnishing is using a tool of a harder material to smooth the surface of a softer material. It is really caused whe the harder material applies enough force to overcome the yeild strenght of the softer material thus enabling a plastic flow of the softer material. This cannot really happen when rubbing hardened steel with leather. Leather would certainly not smear molecules of steel.
Leahther has abrasives in it that do affect steel, but you are abrading at a fine level and polishing…because of those abrasives. You are definitely refining the edge, but certainly not by burnishing.

To comment on the different media, I think that they all have a place in a progression depending on what your gola is. The leather has its own intrinsic abrasive, but it is typically swamped by sprays or pastes applied in quantity down to around one micron (just my experience, not an exact measurement). It also, depending on the type of leather and pressure used is very effective at getting some convexing at the edge of the edge. Leahter is plentiful and cheap. This adds to its value as a medium

Bals has less abrasives of its own and is stiffer. This makes it suitable for finer grits than the leather. Because it is stiff, it does not contribute as much to convexing.It is also relatively inexpensive.

The Kangaroo, as described here recently by Ken Schwartz is an improvement on the previous two in that it is smoother than the leather, has less abrasive of its own, and when mounted directly on aluminum, has very little give. It will hardly convex an edge, like balsa and can be used with finer abrasives because it does not contribute its own.

Nano cloth is just the next in the progression thank to Ken. You con use the finest spryas down to 0.050 and 0.025 microns diiamonds without being concerned about the medai contributing anything.

Now I would not say that balsa trumped leather…etc. I would say that the different media have a place in progressions used to accmplish different goals. If you want to conves your edge a bit, easiuly, you would use leather. If you want to go nuts with a progression, you would go to the nanocloth with fractional micron abrasives.

I have all of the mentioned strops. For 98% of the blades that I sharpen, I finish with the 1 and 0.5 micron sprays on leather.

I wouldn’t bother putting 13 micron spray on nanocloth, because I can use leather which is cheaper and the results will be very close. The same would be said about Kangaroo. I really think that above one micron, you could use balsa and be OK and get pretty similar results.

The right tool for the right job… Try them all and I think you will agree that each media has its place in your tool kit.

8

I don’t disagree with anything you (Phil) said, but I’ve thought about this thread (a lot) since Jacob first posted the question. There is something to be said for consistency… plus having reread some of the old threads where Clay was testing some of the various strops and abrasives and looking under the 'scope (and there was a few surprises)… I too am curious what an entire progression of all 'roo or nanocloth would do. Maybe we’d get a better result out of 14m sprayed on nanocloth… never know without trying?

Surprised actually that noone’s done it (or maybe they just haven’t posted on it).

9

Wow CB
You’ve got five 7’s under your moniker.
Time to go to Vegas

10

[quote quote=“Mikedoh” post=10406]Wow CB
You’ve got five 7’s under your moniker.
Time to go to Vegas[/quote]

I’m tempted to wreck it by adding more Karma, but it’s too cool looking :slight_smile:

11

[quote quote=“cbwx34” post=10405] I too am curious what an entire progression of all 'roo or nanocloth would do. Maybe we’d get a better result out of 14m sprayed on nanocloth… never know without trying?

Surprised actually that noone’s done it (or maybe they just haven’t posted on it).[/quote]

As you Curtis, I have wondered. Not sure whether it was the over application of logic (it can’t make any difference because…) the time involved in verification, or the cost involved in replacing my 16 level progression of strops (12 of which are not kangaroo).. that has kept me from doing it myself.
I would love to see some well documented results… any volunteers??
:slight_smile:

Phil

OH… and call me set in my ways… but I do know that on the macro level…i.e cutting things, and making a blade look pretty, just works!!

12

[quote quote=“wickededge” post=10408]
I’m tempted to wreck it by adding more Karma, but it’s too cool looking :)[/quote]

Perhaps you’d like to weigh in, Clay, on the subject of burnishing discussed previously in this thread.
It was my understanding that burnishing may occur on any sliding surface if the contact stress locally exceeds the yield strength of the material. Which in the case of leather on steel is caused by the high friction between the two surfaces.
But Phil contends that it is not possible for leather to move the molecules of steel, or cause a plastic deformation of, or change to, a steel surface due to sliding contact with the leather surface.
en.wikipedia.org/wiki/Burnishing_(metal)

See this video segment starting from 9m30s:
http://youtu.be/2-YySRRnaR0?t=9m30s
[video size=100 width=425 height=344 type=youtube]2-YySRRnaR0[/video]

13

I’ve read most of the controversy between burnishing or not burnishing on the various threads here. I’ve always been under the impression that the stiction of leather is enough to pull molecules.

However, I’ve always been at war with myself. Logically, burnishing with leather makes absolutely no sense to me. However, being what I’ve always known about stropping, it isn’t so easy to just switch to the other side of the issue. I still haven’t seen very adequate proof to prove the point either way (although some of Clay’s pictures do seem to show metal that has ‘smeared’ or ‘collapsed’ into itself or it’s valleys). The jury is still out on the matter for me, and in the meantime I feel pulled both ways.

14

I will look for threads if time permits… but Clay ans I have discussed this. He has a hypothesis that local pressure can cause plastic flow of metal by applying leather to metal. Even after some very high power (2000 X IIRC) images…remember this is 2000X there were some evidence of something that could resemble plastic flow..i.e burnishing. I think at that point we talked about getting time on an SEM at Sandia labs to further resolve (A bit of a pun…yes) the issue. The problem with the optical results is that the field of view is so small,at the magnifactions used to see the potential effects, that even if highly localized (perhaps caused by “dull” abrasives, not the leather) could be observed, the contribution to what is going on at a macro level is likely insignificant.

I have not looked at the video that was posted. I am sure it changes nothing in the discussion.
I think that the jury is still out on this.

As always, I stand to be corrected and have an open mind on the subject. My contention is that, so far, I have not seen anything to convice me. As many times as I have tried to play with the math, it just does not work out
I am not sure that it is mutual, but I consider Clay to be a freind. He is also probably my top sharpening mentor…even if from afar!!

I am just not ready to buy into the leather burnishing steel thing …yet!

15

[quote quote=“JacobWilson” post=10413]I’ve read most of the controversy between burnishing or not burnishing on the various threads here. I’ve always been under the impression that the stiction of leather is enough to pull molecules.

However, I’ve always been at war with myself. Logically, burnishing with leather makes absolutely no sense to me. However, being what I’ve always known about stropping, it isn’t so easy to just switch to the other side of the issue. I still haven’t seen very adequate proof to prove the point either way (although some of Clay’s pictures do seem to show metal that has ‘smeared’ or ‘collapsed’ into itself or it’s valleys). The jury is still out on the matter for me, and in the meantime I feel pulled both ways.[/quote]

Me too conflicted… But I can tell you one thing… it is not about burnishing, it is physics, you are not smearing molecules, even if burnishing is happening. Even during plastic flow of the surface, there is no way you can smear molecules. To really smear molecules, you need to change their shape. This means changing their geometry. The bonds that hold molecules together give them their physical properties. To smear them you would have to change the molecular shapes, and distort the bonds. Doing that would make them something else. Regardless of whether burnishing steel with leather is possible, you aren’t smearing molecules with your strops.,

Now, I tend to think that we all can agree that stropping works. In the context of this discussion, the real question is why. I contend that it is all due to the abrasives involved. Whether plain leather or charged strops, the abrasives are doing the work. Or so I believe. In no case are we distorting or actually smearing molecules on the atomic scale.

If you have read my other stuff you will know that I am a stickler when it comesto defining terms. I may seem to be a PIA, but I think that the best way to start a meaningful dialog is to make sure everyone is on the same page…

Imagine that…:silly:

16

[quote quote=“PhilipPasteur” post=10415][quote quote=“JacobWilson” post=10413]I’ve read most of the controversy between burnishing or not burnishing on the various threads here. I’ve always been under the impression that the stiction of leather is enough to pull molecules.

However, I’ve always been at war with myself. Logically, burnishing with leather makes absolutely no sense to me. However, being what I’ve always known about stropping, it isn’t so easy to just switch to the other side of the issue. I still haven’t seen very adequate proof to prove the point either way (although some of Clay’s pictures do seem to show metal that has ‘smeared’ or ‘collapsed’ into itself or it’s valleys). The jury is still out on the matter for me, and in the meantime I feel pulled both ways.[/quote]

Me too conflicted… But I can tell you one thing… it is not about burnishing, it is physics, you are not smearing molecules, even if burnishing is happening. Even during plastic flow of the surface, there is no way you can smear molecules. To really smear molecules, you need to change their shape. This means changing their geometry. The bonds that hold molecules together give them their physical properties. To smear them you would have to change the molecular shapes, and distort the bonds. Doing that would make them something else. Regardless of whether burnishing steel with leather is possible, you aren’t smearing molecules with your strops.,

Now, I tend to think that we all can agree that stropping works. In the context of this discussion, the real question is why. I contend that it is all due to the abrasives involved. Whether plain leather or charged strops, the abrasives are doing the work. Or so I believe. In no case are we distorting or actually smearing molecules on the atomic scale.

If you have read my other stuff you will know that I am a stickler when it comesto defining terms. I may seem to be a PIA, but I think that the best way to start a meaningful dialog is to make sure everyone is on the same page…

Imagine that…:silly:[/quote]

I can agree with this. I’m no physicist, but what logical side I have (and you’re persuasiveness) sways me.

17

Just keep in mind, I think the jury is out on the burnishing of hardened steel with leather topic.
Smearing of molecules is a quite distinct concept. I have experienced burnishing of soft metals with a hardnened burnishing tools first hand. It works as advertiesed, no question! So that, while I am sure that the smearing and polishing using the plastic flow of burnishing works, I can’t see molecules being smeared as part of the process.

You just need to think smaller to see why.

Phil

18

When you study the physics of how molecules and atoms work and bind together and move and shift, there are a lot of suprising and amazing things going on.
Like how static electricity and just electricity in general interact with molecules, and how loosely held together some of these molecules are, depending on their structure, and how they interact with each other.
These bonds between molecules are nothing more than electrons shared by atoms.
In some structures, like graphite, the structure is very robust.
In others, molecules can be pushed and moved relatively easily; suprisingly easily in some cases.
When an apple falls off a tree, for example, the molecules in the stem holding the apple lose their electrical bond connections and it falls to the ground. When you touch an object, you are not actually touching atoms or molecules; you are “feeling” the electromagnetic force. This is similar to when you hold two magnets apart with their like-poles facing each other. You feel the magnetic force, which is nothing more than electrons interacting with each other.
When you rub a glass rod with a piece of silk, you are actually rubbing electrons off the glass rod with the silk.
Given some of what I have seen in the world of physics, it does not suprise me at all that the large amount of friction that is created between the surface of the leather and the steel (enough to lift a heavy base off the tabletop) could cause movement at the molecular level on the steel bevel. And when I see the enlarged images, it looks very different to me than the effect I see from mere abrasion.

EDIT: For the record, I didn’t mention “smearing” molecules at any point. That is not burnishing, nor what I was referring to. I am referring to “…the plastic deformation of a surface due to sliding contact with another object. Visually, burnishing smears the texture of a rough surface and makes it shinier. Burnishing may occur on any sliding surface if the contact stress locally exceeds the yield strength of the material…”

19

Great response, and thought provoking. Let me do more research so that I can talk about the steel matrix directly. I think Physists would argue about the surprising part… though I certainly find it amazing.

Keep in mind that the micrographs that showed effects that may be plastic flow were taken at very high magnification. This is what gets people. You are seeing what may be a 10 micon square. If you can pick out only a couple of one micron or less instances in that field of view that “may” suggest plastic flow, what does that tell you about what is going on at the macro level? I would say, on average, very little. I would also point out that a few “dull” micron level abrasive could account for the highly localized effect.

Whenlooking at high magnification photos, the perspective has to be taken into account. It stops being anything that we can relate to directly. Keep that in mind while veiwing them.
Also, the effects that you mention are related to outer electron transfers. Generally these can change the polarity of the outside of a molecule, but the intrisic shape will not change. If it could, that molecule would be intrinsically unstable. I suggest that the iron/carbon/ carbide forming elements in steels do not show this kind of instability. I suggest that though all of the things you mention are valid, they in no way support the idea that we are smearing molecules.

Good talking BTW !!

20

Yes, a good discussion is always interesting. I suspect that the differing opinions expressed here may simply come down to us coming from differing ideas about the definition of the term “burnishing”. I know in the metalwork world, it very specifically means the technique of rubbing a harder metal on a softer metal to achieve the polishing effect.
But bear in mind that in the wider world in general, the dictionary definition of the term “burnishing” is broader, being simply:
“1. to polish (a surface) by friction.
2. to make smooth and bright”
-or words to that effect.
So we can all agree, I think, that from that definition of “burnishing” we are accomplishing that (to a greater or lesser extent) with leather strops, yes?