Strop?

[me_]

I have used the inside of my leather belt to strop my knives for years and have wondered if the strops with compound make a noticeable difference and if so what type of strop and compound is best?

 

[17pes]

I just put together a couple leather strops. I always used to use heavy duty cardboard to strop my folders, which was fine, but I have absolutely seen an improvement in my edges. I tried the strop bare,which was fine and showed improvement with a little time spent stropping, and i now have one with green and black Enkay compounds. The green and black get the edge very nice very quickly. Definitely sold on the leather with compound.

I still have a strop that's naked, but I'm looking at different diamond compounds for that one. I still have enough leather left to make a one sided bare strop if I decide I like that best.

 

[Razorsharp-Travis]

i say start off with 0.5 or 1 micron diamond paste. just search diamond paste in ebay and buy a tube for like, 6 bux. and put a light coat on the inside of your belt

 

[me_]

thanks for the advice

 

[HoosierQ]

I just yesterday put together a balsa wood strop. It's pretty thin, probably 1/4" and extremely light and wouldn't take a beating like my oaken one. But I really like the feel or the action of the balsa against the blade. I "crayoned" some green compound on in a rather haphazard zigzag pattern, careful really only to get the edges covered.

Works very well. My leather strop, glued to oak, is a) not perfectly flat due to imperfections in the leather and slightly warped wood, and b) done on the smooth side.

So I like the action of this balsa. If I can find some sort of perfectly flat substrate like a plywood or something, I may glue it on there to toughen it up.

 

[Obsessed with Edges]

I just yesterday put together a balsa wood strop. It's pretty thin, probably 1/4" and extremely light and wouldn't take a beating like my oaken one. But I really like the feel or the action of the balsa against the blade. I "crayoned" some green compound on in a rather haphazard zigzag pattern, careful really only to get the edges covered.

Works very well. My leather strop, glued to oak, is a) not perfectly flat due to imperfections in the leather and slightly warped wood, and b) done on the smooth side.

So I like the action of this balsa. If I can find some sort of perfectly flat substrate like a plywood or something, I may glue it on there to toughen it up.

MDF (medium density fiberboard) is extremely smooth & flat, and would be perfect as a backing for your leather balsa (or leather too ). Surface texture is much smoother than most plywood, and mdf is inexpensive too.

 

[HeavyHanded]

I have used the inside of my leather belt to strop my knives for years and have wondered if the strops with compound make a noticeable difference and if so what type of strop and compound is best?

A lot of people strop right on MDF, no leather.

The more stropping I do the more I realize this is the real rabbit hole of sharpening. Almost any change in density, surface texture, vehicle (wax, oil, water, dry powders), or abrasive type and grit size will have a noticeable effect on the edge, as well as swarf buildup and compression of the abrasive into whatever backing you're using. I recently put together a travel kit based on a thread re machete maintenance in the field. For a strop I included some rubberized fiber gasket sheeting to wrap around my stone with some compound - it works just as well as some newspaper but can be cleaned off by working a drop of mineral oil into the surface and wiping it off. Have been working on stropping on a maple board using crayon-type compound and a drop of mineral oil to make a slurry. It works great but there are subtleties. For ease of use I still highly recommend a light rubbing of compound on newspaper wrapped tight around a whet stone.

Forum member Stitchawl had a very good response to a similar question where he detailed very clearly how he prepares leather cuts for use as a strop - invloves wetting the leather and compressing it, I cannot recall all the details. A search would be well worth your time - he has a lot of knowledge in this area. The sticky at the top of the page is a good resource too.

 

[HeavyHanded]

Double post...!

 

[Allen R.]

check out robert barber not gonna post his link but he makes a great strop just youtube great strops and youll see who im talking about his strops are awesome.

 

[HoosierQ]

An old fella that basically loafs down at the local Tandy Leather store told me he made a strop with vegtable tanned leather, wetted, and then beaten flat with an old cobblers hammer he has. Compressed the dickens out of the stuff I guess. Not sure how he got it flat but I suppose if you worked at it and maybe sanded it or something afterward. Anyway, I think professional leather strops are compressed in some fashion, presumably rollers for uniformity.

 

[HeavyHanded]

Here's a quick guide:

http://www.bladeforums.com/forums/s...buy-leather-for-strop?p=10892610#post10892610

Wet the leather under the tap. Don't hold it there... just move it around until every part is wet, front and back, then set it aside for about two hours. Put in on the kitchen counter and then roll the heck out of it with a heavy rolling pin. Keep rolling for 10-15 minutes! Now stop and let the leather dry overnight. The next day, use some good quality shoe cream (NOT shoe polish!) that you can buy in any shoe store or shoe counter, and rub just a bit of it into the leather to recondition it. Don't overdo this... a few pea-sized bits of cream is all you need.

This will do two things; it will compress the leather making it a firmer substrate for compound use. (Easier to get sharp bevels on a firm base. If you plan to strop convex edges you might want to cut off that strop before you do all this.) The second thing it will do is cause the natural silicates in the leather to migrate towards the top of the leather to use as the finishing strop. These silicates are the finest degree of finishing grit you may find to use AFTER stropping on compound-covered leather. Then, cut up your strops. Make some bench mounted and some free hanging. You have more than enough leather for both. Then you might want to start advertising selling strops for ridiculously high prices as so many others have here...

Stitchawl

I still haven't tried this, but its on my short list along with steeling on borosilicate (with pics).

 

[stitchawl]

An old fella that basically loafs down at the local Tandy Leather store told me he made a strop with vegtable tanned leather, wetted, and then beaten flat with an old cobblers hammer he has. Compressed the dickens out of the stuff I guess. Not sure how he got it flat but I suppose if you worked at it and maybe sanded it or something afterward.

The fact is... get ready for this... You do NOT need to get it perfectly flat or smooth! If it's a bit lumpy, the knife edge is only going to hit the high spots of the lumps. The fact that you are moving the blade over the bumpy surface means that in each pass, the entire edge will at some point be in contact with the high spots. You aren't going to be getting an uneven effect. Remember too, that stropping is the final stages of the sharpening process. You aren't taking off a lot of metal with each pass. If you've sharpened correctly, you shouldn't need more than a dozen strokes on the strop anyway. Yes, you can use a 9mic compound on a strop, but that's really 'sharpening using compound instead of stone' rather than 'stropping.'

Anyway, I think professional leather strops are compressed in some fashion, presumably rollers for uniformity.

Yes, the better strops are pounded between metal hammers. You can see this action in the video that Horween Leather has for its Shell Cordavan horsehide.

I wish one of you guys with a microscope camera would take some photos of of a piece of 1095 steel that gets stropped on MDF with .5mic compound and stropped on leather with the same .5mic. Then a photo of the same steel stropped on bare high quality horsehide... My guess is that you will not see much difference between the MDF and the leather, but a much finer edge with the bare horsehide.


Stitchawl

 

[HeavyHanded]

I wish one of you guys with a microscope camera would take some photos of of a piece of 1095 steel that gets stropped on MDF with .5mic compound and stropped on leather with the same .5mic. Then a photo of the same steel stropped on bare high quality horsehide... My guess is that you will not see much difference between the MDF and the leather, but a much finer edge with the bare horsehide.


Stitchawl

I have some pics of stropping with compounds down to about .5-1mic, depending on how fine the final stonework is they can show a lot of difference before and after. I don't have any quality horsehide, but have taken before and after pics of plain leather following compound and there's little visible difference(at 640x). I've taken pics of relatively coarse edges at about 800 -1000 grit and stropped with only plain uncoated paper - with and without ink. Visibly (at 640x) the only difference is a change in the reflectivity, the grind pattern appears unchanged. Given that for the light to reflect more brightly there has to be some additional polishing happening, it wasn't enough for me to note any other change - it did cut substantially better. Perhaps with a SEM at 2000x or higher...

 

[Magnaminous_G]

I've wondered about that myself. I'm not sure about the science, but I know that some knife sharpeners swear by plain leather. I know that knifenut often finishes on plain kangaroo leather. I don't have any plain leather strops, but I can definitely tell the difference in the edge after I've stropped on my jeans as a final step. If you watch Rick Marchand, Murray Carter, and many other excellent sharpeners, they finish by stropping on newspaper, laid down over the finishing stone and made wet with water. I've seen other sharpeners who finish on plain cardboard. Personally, I've only ever used a Strop Block, which comes pre-loaded with Chromium Oxide (Green) compound and works very, very well, probably because it cuts steel so well.

I suspect that guys like knifenut get such excellent results with plain leather because they are so good at finishing the edge on the stones and completely removing the burr. When they go straight to bare leather, they really are just uber-refining that edge. Amateurs like me can't get the edge that good off the stones, so the compound on the strop helps a lot to knock the final burr off and refine that edge.

As for which compound works best, most sharpeners I know of use Chromium Oxide (green) compound. I know that many factory and custom knife makers finish with Diamond (white) compound, usually on buffing wheels. And then there are the pastes mentioned above made by companies like DMT, Hand American, etc. But I've never used any of those.

 

[Obsessed with Edges]

..." I know that many factory and custom knife makers finish with Diamond (white) compound, usually on buffing wheels."

FYI, the 'white diamond' compound used on buffing wheels isn't actually diamond. It's tin oxide. More of a rouge-type compound. I'd hate to think how expensive it'd be, if actually diamond and sold in 1 lb. sticks.

 

[tfields]

i mounted a section of an old leather belt to a piant stir paddle and use turtle wax steel polish seems too work fine and about 5 bucks invested!

 

[Magnaminous_G]

FYI, the 'white diamond' compound used on buffing wheels isn't actually diamond. It's tin oxide. More of a rouge-type compound. I'd hate to think how expensive it'd be, if actually diamond and sold in 1 lb. sticks.

Thanks for the clarification. Do you know if Tin oxide cuts better or worse than Chromium Oxide? I've actually got some (it's brick of roughly crayon-like texture), but I've never used it since I bought a Strop Block.

 

[stitchawl]

I have some pics of stropping with compounds down to about .5-1mic, depending on how fine the final stonework is they can show a lot of difference before and after.

The difference I'd like to know is more about the substrate than the yes/no of using compound. I know that good compound plus good technique equals a better edge, but I'd like to see what difference there will be using something like MDF vs firm leather as the base for the compound.

I don't have any quality horsehide, but have taken before and after pics of plain leather following compound and there's little visible difference(at 640x).

That's understandable. Plain leather doesn't do more than any other 'plain' base. The difference comes with whose skin is being used! High quality, properly cased horsehide has a completely different feel to it than even properly cased cowhide. You can feel the hide grabbing the edge to smooth it out!! It doesn't just 'slide' over the surface. I can't begin to explain properly, but the difference is amazing. Used once and you'd never look back...


Stitchawl

 

[Rick Marchand]

What you use isn't as important as how you use it. Once you understand the basic principles behind getting things sharp, you can take it as far as you want. I used to get downright silly. These days, I am happy with a good working edge. Thanks for mentioning me Mag-G! I am flattered.

 

[Obsessed with Edges]

Thanks for the clarification. Do you know if Tin oxide cuts better or worse than Chromium Oxide? I've actually got some (it's brick of roughly crayon-like texture), but I've never used it since I bought a Strop Block.

Tin oxide apparently is at ~ 6-7 on the Moh's scale of hardness (some knife steels are in the same range), and therefore is a lot less hard than chromium oxide (~ 8.5 Moh's). As a rouge/buffing compound used on powered buffing wheels, it might polish (some) steel OK. But, I'd think it'd be pretty slow-working by hand on a strop, for a hardened knife steel.