Stropping - Wood vs Leather?

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Rhodies

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I've read about the process of casing a leather strop and the desired result of a much firmer leather. If you use compounds, would that not achieve the same sharpening result? With both substrates being firm, is there a role each would play or would the outcome be similar? I know there are other methods of stropping but please, in your replies, limit them to these two.
 
Rhodies, either would work to improve the edge. Especially adding slurry. The leather will get spongey in time but this will help with burr removal and covers the scratches. Whereas the board will show the scratches. When you do it use a 1 1/2" thick board for either one. So, this
allows some room for the handle of the knife with fingers wrapped around to pass. DM
 
Casing the leather (which is just the wetting and allowing it to dry a little before working it, making it malleable,) to make a strop, and then rolling (or pounding,as is done in the process of making cordovan horsehide,) does two things; it allows the leather to be compressed, and because of that compression, allows the natural silicates to migrate to the surface of the leather.

These natural silicates tend, on average to be much smaller than most available compound grits, although if one is willing to spend the money, you can get some very fine grits these days. So... generally speaking, when using a properly made leather strop as the final finish to edge making, you will get a better result. Anecdotally, ask yourself why barbers have been using bare horsehide strops to shave their customers for all of recorded history? Money talks. If customers weren't satisfied, they wouldn't return for another shave.

As to the second part of your question, yes, there IS a difference applying compound to leather or to wood. Even boiled leather will not be as hard as a piece of Oak. It's easier to maintain a flat bevel on a harder substrate if that is your goal. Some folks think that there is a difference in the adhesion of compound when applied to leather or wood. Fact is, adhesion is not really so important... With compounds, all one needs is the tiniest amount of 'color' to get the job done, not a smooth layer of 'peanut butter.' If you use powdered compounds, an amount the size of this '0' will work just as well as a tablespoon full. Just ask any gem polisher. They don't slather the stuff onto their wheels.


Stitchawl
 
Well, I have polishing wheels to polish knife frames and blades and I do slather it on to the wheels. The difference is the speed at which the
wheels spin and the compound that gets the desired finish on blades. Some is lost to just the spinning force of the wheel. Nor would I apply
slurry to a strop like I do to a polishing wheel. As it's two very different items. My strops as you say, I roll them and try to get them firm. DM
 
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Thanks fella's for your replies. I ended up ordering a 2 × 3 x 12" piece of Basswood to give it a go. Would like to seperate two sections on the Basswood to apply a .5 & 1.0 micron diamond paste. I have a Strop I got last Fall that has not been "Cased" and applied the Green Chromium Oxide to it and have learned the greater number of strokes you apply can prove detrimental to the sharpness of ypur blade. The fewer the better.
 
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Everything is on a continuum from stuff like diamond plates or ceramics to leather or linen strop. Between you have vitreous stones, waterstones, lapping films, wet/dry, knife boards (hard strops), and softer strops.

All of these can be described by how immobile is the abrasive, how much give it has in line with the direction of movement and how much give it has away from the application of force.

These three factors and two others (the amount of abrasive potential per unit - the mineral characteristics of the abrasive particle, and the speed of contact) account for the mechanics of abrasion and how it effects the steel, mostly in terms of shape/angle of force and burr formation. This is true of grinding as well as stropping.

Stropping on a surface with give is at one end, ceramics and diamond plates at the other.

Folks used to and still do in some regions, use loose grit on wood and other hard surfaces to actually sharpen tools, this normally being done on an open grain hardwood like oak, but I've seen folks honing agricultural tools with grit on the sidewall of a horizontal truck tire.

You can also do this with regular honing compound and a drop or two of oil.

Per the above, using compounds on wood will make for a more pronounced scratch pattern at a given grit size.
 
HeavyHanded said:
Everything is on a continuum from stuff like diamond plates or ceramics to leather or linen strop. Between you have vitreous stones, waterstones, lapping films, wet/dry, knife boards (hard strops), and softer strops.

All of these can be described by how immobile is the abrasive, how much give it has in line with the direction of movement and how much give it has away from the application of force.

These three factors and two others (the amount of abrasive potential per unit - the mineral characteristics of the abrasive particle, and the speed of contact) account for the mechanics of abrasion and how it effects the steel, mostly in terms of shape/angle of force and burr formation. This is true of grinding as well as stropping.

Stropping on a surface with give is at one end, ceramics and diamond plates at the other.

Folks used to and still do in some regions, use loose grit on wood and other hard surfaces to actually sharpen tools, this normally being done on an open grain hardwood like oak, but I've seen folks honing agricultural tools with grit on the sidewall of a horizontal truck tire.

You can also do this with regular honing compound and a drop or two of oil.

Per the above, using compounds on wood will make for a more pronounced scratch pattern at a given grit size.
Click to expand...

Thanks for sharing what you know and taking time to post your own experiences. Would using the Basswood w/Diamond Compound be as sharp as with a "Cased" Leather Strop? You mention scratches, would that play a role in the keenness of the edge giving it bite or just for appearance sake? Are we splitting hairs between an effective edge using Wood vs Leather?
 
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Rhodies said:
Thanks for sharing what you know and taking time to post your own experiences. Would using the Basswood w/Diamond Compound be as sharp as with a "Cased" Leather Strop? You mention scratches, would that play a role in the keenness of the edge giving it bite or just for appearance sake? Are we splitting hairs between an effective edge using Wood vs Leather?
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It will change how much bite there is, I don't know if "sharper" is going to be applicable - if the set-up is good both methods will improve a sharp edge. If the scratch is more pronounced it is definitely going to effect the apex. On hardwoods you can actually apply more force and have less chance of rounding the edge, tho the chance of raising a burr or folding the apex a bit will increase.

The other issue when working with wood is it tends to polish itself, eventually it might cause the abrasive to not hold still well enough to cut the steel effectively, but this is easily fixed by scuffing the wood. On softer woods or open grain hardwoods this is less likely anyway.

The leather or Basswood might hold the compound better, is tough to say. I'm sure they are both effective.
 
Having used and favored basswood for most of my compounded stropping, I can say one would have to REALLY lean into it to actually raise a burr against this wood, if it's even possible to do so. It's firmer than balsa, but still 'soft' enough that it's virtually impossible to burr the edge or roll it, UNLESS one were using very coarse-grit compound, which might raise some noticeable burrs with moderate-to-heavy pressure applied. In that case, it's more about the grit than the substrate. But with the polishing-grade compounds I've used, including diamond in the 1 - 6µ range, and aluminum oxide in the 3 - 10µ range, I've never been able to raise a burr on a basswood strop, even when deliberately upping the pressure. The wood will sooner give way, by denting or gouging before the edge deflects, if anything.

Both balsa & basswood seem to do a lot better in giving compound a strong, more aggressive foothold, as compared to leather. The thing I noticed immediately, the first time I started using wood for stropping was, it removed metal a lot more aggressively (faster) than when I'd tried the same compounds on leather. The wood strops blacken up very fast in use, whereas the leather strops gradually 'gray' over some time, with use. That tells something about how the substrate helps the compound work.

The basswood I've used for stropping is thick enough, it's easy to completely remove the top layer of dirty swarf and expose clean, fresh wood underneath. Can be done by sanding it, or I've liked using a block plane to just 'shave' a thin layer from the top; that also leaves the surface very smooth & FLAT, and completely clean. This is a big advantage also, if you choose to re-purpose a given block for a different compound, and don't want to worry about the older compound contaminating the new strop. If not wanting to completely strip a layer away, it's also easy enough to just scrape the surface with something to take most of the heavy swarf off. I've sometimes done this with the burred edge of a metal paint scraper (like a putty knife, but wider). I used a file to burr the edge, in a similar manner a card scraper for wood-finishing is prepped with a burr. OR, as can be done with a leather strop, just wiping down the strop with a microfiber towel moistened with WD-40, mineral spirits or another similar solvent will remove most of the heavy black stuff, sufficient to make the surface take a new application of compound easily. There're lots of ways to clean these up, none of which are especially difficult.
 
Obsessed with Edges said:
Having used and favored basswood for most of my compounded stropping, I can say one would have to REALLY lean into it to actually raise a burr against this wood, if it's even possible to do so. It's firmer than balsa, but still 'soft' enough that it's virtually impossible to burr the edge or roll it, UNLESS one were using very coarse-grit compound, which might raise some noticeable burrs with moderate-to-heavy pressure applied. In that case, it's more about the grit than the substrate. But with the polishing-grade compounds I've used, including diamond in the 1 - 6µ range, and aluminum oxide in the 3 - 10µ range, I've never been able to raise a burr on a basswood strop, even when deliberately upping the pressure. The wood will sooner give way, by denting or gouging before the edge deflects, if anything.

Both balsa & basswood seem to do a lot better in giving compound a strong, more aggressive foothold, as compared to leather. The thing I noticed immediately, the first time I started using wood for stropping was, it removed metal a lot more aggressively (faster) than when I'd tried the same compounds on leather. The wood strops blacken up very fast in use, whereas the leather strops gradually 'gray' over some time, with use. That tells something about how the substrate helps the compound work.

The basswood I've used for stropping is thick enough, it's easy to completely remove the top layer of dirty swarf and expose clean, fresh wood underneath. Can be done by sanding it, or I've liked using a block plane to just 'shave' a thin layer from the top; that also leaves the surface very smooth & FLAT, and completely clean. This is a big advantage also, if you choose to re-purpose a given block for a different compound, and don't want to worry about the older compound contaminating the new strop. If not wanting to completely strip a layer away, it's also easy enough to just scrape the surface with something to take most of the heavy swarf off. I've sometimes done this with the burred edge of a metal paint scraper (like a putty knife, but wider). I used a file to burr the edge, in a similar manner a card scraper for wood-finishing is prepped with a burr. OR, as can be done with a leather strop, just wiping down the strop with a microfiber towel moistened with WD-40, mineral spirits or another similar solvent will remove most of the heavy black stuff, sufficient to make the surface take a new application of compound easily. There're lots of ways to clean these up, none of which are especially difficult.
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Do you feel a need to rough up the surface of the Basswood with fine sand paper in order for the compound to adequately adhere?
 
Rhodies said:
Do you feel a need to rough up the surface of the Basswood with fine sand paper in order for the compound to adequately adhere?
Click to expand...

I've never felt the need to do so. But with some stick-type compounds, I could see that it may help somewhat. With those, in my own uses, I've just 'crayoned' a diagonal, cross-hatch or zig-zag pattern onto the wood, and that works fine.

And if you were to use sandpaper, something coarser would likely work better anyway, such as ~ 60 - 120 grit. Basswood is already pretty smooth, even saw-cut straight from the store, so a 'fine' sandpaper would likely make it even more so. It takes a pretty coarse sanding to make it noticeably 'roughed up' on the surface.

For polishing-grade compounds, using a paste, spray or other compound makes application simpler. And for pastes especially, a smoother surface actually makes the paste easier to spread more uniformly. Too coarse, and the paste will tend to be grabbed & held in smaller, localized spots. A thin & flexible plastic 6" ruler is what I often use as a spreader, in applying paste compounds in a uniformly thin coverage.
 
Not trying to derail.

What surfaces found at home would work well with 1 micron diamond paste other than leather?
Thanks
 
BellaBlades said:
Not trying to derail.

What surfaces found at home would work well with 1 micron diamond paste other than leather?
Thanks
Click to expand...

I've used it on simple paper (printer paper) over a relatively smooth stone (fine/uf ceramic, black hard Arkansas, etc), or plate glass. Same could be done with paper over wood, so long as the wood underneath is flat, smooth & firm. Can be used on bare wood as well, with the same provision. I tend to think a closed-grained wood works better with finer compounds in general, being smoother with less roughness or bumpiness. Per the earlier discussion, basswood qualifies pretty well.
 
BellaBlades said:
Not trying to derail.

What surfaces found at home would work well with 1 micron diamond paste other than leather?
Thanks
Click to expand...

Denim and canvas come to mind, but both should be wetted and rolled to compress them first, allowed to dry completely before adding compound, so to avoid more of a convex edge.

My old teacher (a custom shoemaker) used a strop made of canvas that had years of compound and swarf built up on it. Looked like a sheet of marble! He never cleaned it, just added a few strokes of compound to it a few times a year.


Stitchawl
 
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