I can't strop

W

wacki

Joined
Sep 12, 2009
Messages
319
Equipment

  • bark river green and black compounds.
  • Nice double sided leather strops from knives ship free
  • black side shows a good mix of leather and black compound.
  • green side is pretty solid green with compound

Technique
I did
  • 20 strops per side with black. (40 total)
  • Then 20 strops per side on green. (40 total)
  • I used a Sharpie to make sure I was getting the edge. (guessing 30 degrees)
  • Light "shaving" strops barely more than the weight of the Rodent Solution blade.

Results

Sucky.

The edge fails the paper test. I hold paper up with one hand and I have to really work the blade to cut it. It's not a clean cut either. It doesn't glide through like my other knives do.

No clue what I'm doing wrong.
 
Last edited:
Does your knife cut the paper before you use your strop? If not, then you need more time on your stones or whatever you use for sharpening. The strop is to refine the already sharp blade, not to sharpen it. The compounds are not designed to abrade the metal enough to sharpen a dull blade. I am right there with you, as I suck at using a strop also. It takes a good technique and practice to finish on a leather strop, and I have yet to master it to the point that my blades are sharper after using my strop, than they were after sharpening them with my sharpener. There are lots of people on here that can get good results with a strop, and my hat is off to them. What I am saying is that it is more than running your knife up and down the strop. So don't beat yourself up about it. Just read and research and practice what you learn.

Blessings,

Omar
 
Best to have a sharp edge after your first (rough) stone.
After finishing with the stones, you should be able to cut hair.
Stropping should bring it to shaving sharp.
I could be wrong but that's what works for me.

Edit: I also find that the angle isn't nearly as important as making sure you don't roll the blade when you pick it up. Make sure it comes straight up off of the strop.
 
Does your knife cut the paper before you use your strop?
Click to expand...

Yes but I've had the knife for 6 months and it's been used heavily. I have a spyderco sharpmaker coming to me now (just bought it) so I'll get it razor sharp with that and then try re-stropping.
 
Last edited:
Once you've got a sharp edge from stones. Try 5 feather light strokes per side on green compound. Done (or add 10 strokes per side on bare leather then done).

As stated above, there were way too many strokes on very agressive compounds black (3K) & green (6K), the edge got degraded with burr and or wire-edge. A good & common strop green compound (such as from HA) usually around 0.5um (30K grit). BR green CrO size around 4-5um which will cut super fast, similarly SiC at 6-8um will also remove metal too fast.

edit: HA = HandAmerican. Good product with tight CrO particle size distribution probably has no particle larger than 0.6um. Unlike many other CrO products where purity & distribution are very poor. First CrO product I got was a bar of woodcraft green compound (regular not super-fine), I saw some scratches what look like from 6um instead of what I thought of 0.5um +- 1um.
 
Last edited:
there were way too many strokes on very agressive compounds black (3K) & green (6K), the edge got degraded with burr and or wire-edge.
Click to expand...

How do you fix a burr or wire edge?

Shouldn't the bark river compounds be good enough to get paper slicing goodness? One person suggests the compounds aren't aggressive enough and you are saying they are too aggressive. After a little research on speculated grit size, I'm inclined to believe you. But I'm still shocked that I can't get a good edge with green compound no matter how many strokes I use.

I'll pick up some hand american.
 
wacki said:
How do you fix a burr or wire edge?
Click to expand...
give this method a try http://www.youtube.com/watch?v=l2ynSDYEUYI

Shouldn't the bark river compounds be good enough to get paper slicing goodness? One person suggests the compounds aren't aggressive enough and you are saying they are too aggressive. After a little research on speculated grit size, I'm inclined to believe you. But I'm still shocked that I can't get a good edge with green compound no matter how many strokes I use.

I'll pick up some hand american.
Click to expand...
It is more about strop degrading your edge (I assume that your edge off the stone is already paper slicing sharp). I only strop on bare leather or white-compound (12um AlO) on the nap side of leather - balanced-strop. Other than that, I don't like strop because it's very easy to ruin a good edge. With practice & experimentation you can get good with general stropping too. As for myself - I like simple & flexible process that create a predictable result 99% of the time. OK, most 2 important things to keep in mind when do general stropping on a reasonably hard backing:
a. gentle pressure
b. less strokes (should be more than 10 per side)

I suck at a & b - that was why I settle for balanced-strop. Lol - I use it to refine, major+minor touchup and polish an edge, so it's not really fits in everyday strop, where everyday strop supposes only to refine & minor touchup an edge.
 
I used to suck at stropping too. I used green CrO and normally made the knife more dull. For one, the knife has to be sharp. The strop is just to refine the edge and make it sharper, but it needs to at least shave hair when you start. Second, diamonds are what made the difference for me. I put 1 micron diamond spray on a good strop and immediately had good results. I use 1 and 0.5 micron Hand America diamond spray. It's a little pricey compared to a block of compound, but a bottle will last you a decade if your not making a living stropping knives. Last, you want to use a slightly more acute angle than you sharpened at so you don't round the edge. At least that is what works for me. The sticky on stropping angle explains things quicker than I can explain it (if I remember correctly).

If it were me and I was going to make a Hand America order, I would get the diamond spray. If I remember correctly I got both bottles and some freebies for around 30 bucks and I consider it one of the best things I have bought for sharpening.

As a side note, I strop my knives after every couple days of using them. It brings them back to tree topping sharp (arm hairs, not real trees :) ) without the need to do a real sharpening. Works great unless you use a knife hard and dull it so it no longer shaves. Then a touch up on something like a Sharp Maker is needed.

Edit: Also I think most people try to go too fast which makes holding the right angle difficult or impossible. It also leads to rolling the knife at the end of the stroke which will round the edge. It should take a couple seconds to place the knife, make the stroke, pick it up, and place the knife back down. I just read where someone said they make like 2 strokes a second. That is way too fast and I doubt will result in a sharper knife unless maybe you are a seasoned pro at stropping.
 
Last edited:
wacki said:
How do you fix a burr or wire edge?

Shouldn't the bark river compounds be good enough to get paper slicing goodness? One person suggests the compounds aren't aggressive enough and you are saying they are too aggressive. After a little research on speculated grit size, I'm inclined to believe you. But I'm still shocked that I can't get a good edge with green compound no matter how many strokes I use.

I'll pick up some hand american.
Click to expand...

Green compound is at it's best when refining an edge that's already good (or very good). In other words, for an edge that is already at least shaving, it'll take it another notch or two beyond (to tree-topping hair, or hair-whittling, etc.). Generally should only take maybe 10 passes per side, when doing this with green compound. Much longer than that, the edge probably isn't ready for it. Green really excels on carbon steels (1095, CV, etc.) and simpler stainless (420HC/440A/etc.). If one has to spend more than perhaps five minutes stropping with green, it's more likely to result in dulling/rounding of the edge. It's very, very difficult to make a good edge with the green, if the edge isn't ready for it. This is generally true with most stropping, but really reveals itself with the green compound. It's not aggressive enough to really re-form an edge to make it sharp in the first place (grit is too small, not as hard as other compounds like AlOx or SiC or diamond).


David
 
It's very, very difficult to make a good edge with the green, if the edge isn't ready for it. This is generally true with most stropping, but really reveals itself with the green compound.
Click to expand...

This is what baffles me. There are a huge variety of stropping compounds out there all the way up to 45 microns in size. If you start big and then progressively go smaller, how hard is it to get a good edge?

I'm trying to figure out why stones are better than stropping at comparable grit size.
 
wacki said:
This is what baffles me. There are a huge variety of stropping compounds out there all the way up to 45 microns in size. If you start big and then progressively go smaller, how hard is it to get a good edge?

I'm trying to figure out why stones are better than stropping at comparable grit size.
Click to expand...

The biggest difference is what the grit is embedded in. A stone works more efficiently at grinding & honing, and actually forming the edge, because the 'hard' substrate/binder doesn't compress or give like a soft backing (leather strop). A 45µ particle doesn't perform anywhere nearly as such on a soft 'bed' like leather, because it will sink in or recede under the pressure from a knife blade. On the other hand, a stone with the same 45µ grit won't 'give' in the same way (if at all), so the larger particle will dig much more aggressively into the steel. With green compound on leather, the typical particle size of 0.5µ can only do so much abrading, because it's limited by both the small particle size and by the soft backing. I usually think of this in terms of sliding on gravel in your bare feet. If the gravel is on bare concrete, it's going to hurt a lot more and bite a lot deeper than if you were sliding on the same gravel scattered over a dense & thick, but much softer carpet with padding underneath.

This is why stropping is better-suited to the very fine refinement and final touches on an edge, after that edge is completely formed on stones. It's meant to be done with a very light touch, and in a minimum of strokes. If used in the proper context at the proper time, the 'light touch' is aided by the softer substrate (leather), so long as minimal pressure is exerted on the edge. If the edge isn't already pretty well-formed (fully apexed), it's very difficult to finish forming it with compound on a soft backing like leather, which compresses and tends to roll/form itself around the apex. The longer one goes at it, the more the edge will round over, as opposed to getting sharper.


David
 
Last edited:
I started with bare leather. When I was skilled enough to improve an already sharp edge with that I added compound. It doesn't take long (trial and error) to see what works.
There is some great info in this thread.
 
You must log in or register to reply here.
Back
Top