Troubleshooting my Strop/Stropping Technique

[Luke Dupont]

Hi everyone. I've been sharpening for a little while now, having gotten into woodworking - and I'm beginning to get confident in my ability to get a good edge with stones. What I can't seem to figure out, however, is the use of a strop with compound; I've tried several strops with leather, MDF, and balsa-wood, and I've tried all manner of techniques I've read/watched videos about, from woodworkers to the knife and straight-razor crowd. However, every time I strop with compound, I make my edge duller. Guaranteed.

So, what gives? I've actually had some success stropping knives just on my leather belt, without any compound. And I've even done the same on MDF or endgrain for my plane irons and chisels, to remove the burr. But as soon as I put on compound, I get a rounded off, dull edge, no matter how lightly or carefully I work. This is the compound that I am using, by the way: http://uedata.amazon.com/Dovo-Strop-Paste-Black-Part/dp/B001LY40Q4
I know most people use the green, or white chromium oxide. I didn't buy this compound specifically, but rather got it from a family member who was into straight razors for a short time (and, didn't seem to have much success sharpening himself.)

As far as technique goes, I try very carefully not to go at an angle that would round off the edge, and I use very light pressure. But, I've recently seen woodworkers go quite haphazardly at it compared to what I'm doing, and still get good results, so I'm starting to wonder if it's not my technique, but the compound, or my strop, or how I'm putting the compound on the strop. I'm currently using a double-sided strop with leather on one side, and MDF on the other. I thought the MDF would solve my problems, being that it would give less and therefore be less likely to round off my edge, but nope; same result as leather with compound.

Maybe I'm using the compound wrong? How much am I supposed to use/not use? Is it supposed to be fresh, and wet, or dry? I'm really at a loss. Is there anything I can look for to troubleshoot what I'm doing wrong?

[Patrick Chase]

Hi everyone. I've been sharpening for a little while now, having gotten into woodworking - and I'm beginning to get confident in my ability to get a good edge with stones. What I can't seem to figure out, however, is the use of a strop with compound; I've tried several strops with leather, MDF, and balsa-wood, and I've tried all manner of techniques I've read/watched videos about, from woodworkers to the knife and straight-razor crowd. However, every time I strop with compound, I make my edge duller. Guaranteed

It may be that your stones are capable of leaving a finer edge than the "mystery compound" that you're using. What's your finishing stone?

This is a problem even with popular honing compounds for woodworking. Many people claim that the common "0.5 micron Chromium-oxide" compounds on the market are the equivalent of #20000 or #30000, but they're not. Those compounds contain a high percentage of larger Al-Oxide particles as well, such that they leave a finish roughly on par with a (non-Shapton) #6000 waterstone. When I look at my edges under a microscope I see finish and edge quality go *down* if I strop with that stuff after honing on a high-grit (#10000 or above) stone, though it's arguably not a problem because in either case you're into diminishing returns for woodworking.

[Luke Dupont]

Nah, it gets pretty dull. As in, something is very wrong with whatever I'm doing; I can get a better edge with 400 grit sandpaper, or my coarse diamond stone.
Usually I sharpen to 1000 or 2400 grit on my Japanese waterstone, or even just a mystery grit Arkansas stone that I have, which seems to leave a very fine edge. But, stropping with compound dulls my blade to the point that I can hardly cut paper.

I've also googled to see if anyone else was having trouble with the Dovo paste that I use, and people seem to like it just fine *shrug*

[Jim Koepke]

Howdy Luke and welcome to the Creek. Your location isn't listed in your profile. If you are in the Pacific Northwest I would be happy to get together to see if your stropping troubles can be sorted.

I am not familiar with the stropping compound you are using. That is the first thing I would consider. Some folks strop on a piece of leather without compound, others even use paper from a standard grocery bag. The material isn't as critical as the procedure.

One of the books I have is volume one of Chris Pye's carving series. In it he says no more than 10 strokes on the strop. I have heard another woodworking 'guru' suggest "30 or so" on each side of a blade. The more one strops, the more likely the blade will be dubbed. My procedure is to do just enough to remove any burr.

When stropping I am not working fast, I am working with care. Care to lay the back of the blade flat on the surface before pulling it off. I am just as diligent if not more so when stropping the bevel side. I try to put very little pressure on the actual edge. If the blade is lifted too much, it is like creating a secondary bevel with a convex surface.

For chisels and plane blades my strop is a piece of hard leather usually sitting on my drill press table. It doesn't take a lot of the stropping compound. I do not like to recharge often. If there is too much compound on the strop, it comes off on the blade. If a blade comes off the stones with a sharp edge I will often forgo stropping.

jtk

[Luke Dupont]

Hey - thanks for the offer! I'm down near the gulf coast though, unfortunately, so that would be quite a trip ;)

I definitely do get a lot of compound coming off on my blade; this happens almost regardless of how much I put on or not. Maybe it's not sticking well enough to my strop? If the paste is loose or thick, would that potentially cause the dulling action that I'm getting?

I guess I don't need to use compound, but I wanted to learn how to get my blades sharper than what I get from my stones, and have something to be able to easily hone and keep them sharp on a regular basis without having to revisit the stones too often. I've been having a bit of trouble with tear-out, so this has been part of my quest to tame that; I think I'm just not getting (and keeping) my blades sharp enough to work with some of the grain that I encounter.

[Jim Koepke]

Hey - thanks for the offer! I'm down near the gulf coast though, unfortunately, so that would be quite a trip ;)

I definitely do get a lot of compound coming off on my blade; this happens almost regardless of how much I put on or not. Maybe it's not sticking well enough to my strop? If the paste is loose or thick, would that potentially cause the dulling action that I'm getting?

I guess I don't need to use compound, but I wanted to learn how to get my blades sharper than what I get from my stones, and have something to be able to easily hone and keep them sharp on a regular basis without having to revisit the stones too often. I've been having a bit of trouble with tear-out, so this has been part of my quest to tame that; I think I'm just not getting (and keeping) my blades sharp enough to work with some of the grain that I encounter.

A big help in getting blades sharp is to test them and determine a degree of sharpness. There are many tests people use. For woodworking one of the easier and safer tests is a blades ability to pair end grain on a soft wood. If a blade can take a consistent thin shaving from the end of a piece of soft pine, it is likely sharp enough for woodworking. (Maybe this is another photo op for later today in the shop.)

In the post linked below I show two tests:

http://www.sawmillcreek.org/showthread.php?158373-My-Camber-Blade-Round-Tuit-Finally-Came

If you have a sharp blade and are still getting tear out, then there are other things worth consideration. Shaving thickness is a contributing factor. The thinner the shaving the less likely for there to be tear out. With bevel down planes there is also the cap iron to consider. A web search on > setting a cap iron < should find an article on Wood Central by David Weaver that helps with understanding the action of the cap iron, aka chip breaker.

The biggest contributor to tear out is the wood being worked. Some wood just does not want to cooperate.

jtk

[Jim Koepke]

(Maybe this is another photo op for later today in the shop.)

Took the camera out to the shop and decided a video might be better even though my camera is not great at doing this.

Should be up and running at:

https://youtu.be/pT8Lnzvu0cs

I also took a picture for a clear view of the work piece:

334427

On the left is the surface left by the saw. The chisel work is on the right.

jtk

[Prashun Patel]

I am not an expert in stropping... But, I have found it to be super easy to do.

Before you buy any new compound, I would analyze your technique and the substrate your stropping from. Have you tried a piece or hard wood?

What is your technique and how fast are you going?

Also, what exactly are you stropping? a chisel or plane blade?

Last, are you sharpening with a honing guide or free-hand? I assume you're stropping free-hand.

[Patrick Chase]

Jim, out of curiosity do you know the composition of the powder you're using? It's obviously at least partially chromium oxide, so I'm mostly asking if it's pure?

IMO pure 0.5 micron Cr-oxide is a great stropping compound. It isn't as fast as stuff that has coarse calcinated alundum added like LV green, but it leaves a really good finish.

EDIT: Nice background music.

[Luke Dupont]

Took the camera out to the shop and decided a video might be better even though my camera is not great at doing this.

Should be up and running at:

https://youtu.be/pT8Lnzvu0cs

I also took a picture for a clear view of the work piece:

334427

On the left is the surface left by the saw. The chisel work is on the right.

jtk

Thanks! That's a nice video. And geez, that's a sharp chisel! I can pear end-grain, but not quite that effortlessly on Southern Yellow Pine.


I am not an expert in stropping... But, I have found it to be super easy to do.

Before you buy any new compound, I would analyze your technique and the substrate your stropping from. Have you tried a piece or hard wood?

What is your technique and how fast are you going?

Also, what exactly are you stropping? a chisel or plane blade?

Last, are you sharpening with a honing guide or free-hand? I assume you're stropping free-hand.

I started with chisels and plane blades, but I switched to knives until I figure out what I'm doing, since I don't like to have to keep fixing the edge of my chisels and plane irons :P I've tried using a jig even, to be absolutely sure that it wasn't something I was doing, and going slow and light, pulling backwards. Same results.

I've gotten good results with knives using a leather belt without any compound, and following technique that the straight razor folks use; keep the back in contact at all times, keep it light, and flip it over the spine when you change direction. However, same technique on my strop with compound, and I dull my knife. I find the compound doesn't stick to whatever I put it on very well, and I did put a lot. I wonder if that's causing my issues...

[Jim Koepke]

Jim, out of curiosity do you know the composition of the powder you're using? It's obviously at least partially chromium oxide, so I'm mostly asking if it's pure?

IMO pure 0.5 micron Cr-oxide is a great stropping compound. It isn't as fast as stuff that has coarse calcinated alundum added like LV green, but it leaves a really good finish.

EDIT: Nice background music.

Saying powder instead of bar was one of my mistakes. The bar came from a lapidary shop. It was bought a couple of years ago and I am not sure if the person there was sure if it was chromium or not. Lapidary language is a bit different than woodworking or metal working language. I just asked for the finest they had. Before that I used 'jeweler's rouge' which is too soft for hard metal. It works great on gold and silver.

Glad you like the music, not much of my time is spent in the shop when the music isn't playing.

jtk

[Lenore Epstein]

I'm not a stropper, just curious.

I've had the impression that you strop to refine a sharpened edge or touch up a slightly worn edge, but Luke is only honing to 1000 or 2400 on waterstones, sometimes a little finer on an oilstone, before stropping. Would he get better results if he sharpened to a finer grit, say 5000 or so, before going to the strop?

[Archie England]

I'm not a stropper, just curious.

I've had the impression that you strop to refine a sharpened edge or touch up a slightly worn edge, but Luke is only honing to 1000 or 2400 on waterstones, sometimes a little finer on an oilstone, before stropping. Would he get better results if he sharpened to a finer grit, say 5000 or so, before going to the strop?


I believe so.

I've found myself dubbing (rounding over) edges on leather, too (with or without compound). Finally, I've just stopped using any compound on the leather, allowing it to polish only--and I do love the brightening effect. However, Leather with or without compound really doesn't "produce" a better edge than the stones (IMO), it merely polishes the established edge (and will do some honing) by removing the micro-serrations (stone scratches) at the edge. This is definitely what you want. However, I've replaced the leather essentially by buying a high grit level stone. Coming off my 1000 or 3000 waterstones, my blades are sharp! If I attempt to pair SYP endgrain, then the surface shows crushed fiber endings and is still not silky smooth, plus pushing the blade through meets a lot of resistance. At 6000, the chisel meets less resistance and the surface shows less crushing. Any thing beyond that (8k, 10k, 13k, etc), the chisel meets very little resistance in slicing through the endgrain and the surface is silky sheen, with no crushed fiber evidence.

In the end, leather can sometimes improve the edge to the point of easier slicing; but for me, the higher grit stones are far better at achieving this and are more reliable. The Naniwa 8k Snow White stone is perhaps the best compromise, while the Chosera 10k is overpriced (but good). My favs are Sigma 10k or 13k (I really can't tell the difference in results yet the stone characteristics are very different--10 is silky and has a great "feel"; 13k is hard, non-responsive. Yet, both produce amazing edges. YMMV

[Jim Koepke]

Would he get better results if he sharpened to a finer grit, say 5000 or so, before going to the strop?


I believe so.

I concur.

An interesting reality, I have finished a blade on my 8000 Norton that can smoothly shave arm hair. A few misdirected slaps on the strop and it will not. Also have polished a blade on the same stone without getting to the point of smooth shaving. After a few careful strokes on the strop it can be brought to a point of smooth hair removal.

There is a point where the result is not so much due to what is being used as how it is being used.

jtk

[Patrick Chase]

I concur.

An interesting reality, I have finished a blade on my 8000 Norton that can smoothly shave arm hair. A few misdirected slaps on the strop and it will not. Also have polished a blade on the same stone without getting to the point of smooth shaving. After a few careful strokes on the strop it can be brought to a point of smooth hair removal.

There is a point where the result is not so much due to what is being used as how it is being used.

jtk

I think it depends on which version of "stropping" we're talking about. If it involves a media with "give" like leather, then the more you work the edge the more rounding you get. In that case you don't want to make the strop do too much work.

On the other extreme if you're talking about diamond paste on steel then there is no such issue. Ditto for Tom King's diamond lapping film on granite from the other thread. Lapping compound on maple or MDF are somewhere in between, though undoubtedly closer to steel/granite than to leather.

[Luke Dupont]

Hi guys. Just wanted to give an update: I switched to the green compound that I see everyone using (Chromium Oxide?), and magically, I can strop!

My chisels are now sharper than anything I've ever experienced :D

I also changed my technique when sharpening my chisels. I quit being concerned with maintaining a perfect angle, and just eye it maintaining, very roughly, about 30 degrees-ish, creating a slight convex bevel, working the entire bevel evenly and progressing quickly through my diamond stones from coarse, to medium, fine (about 1200 grit), then I hit 2500 grit sandpaper briefly to take out the rough scratch marks left by the diamonds and refine the edge, and then strop. Chisels came out wonderfully sharp, and it was all very quick; much more so than what I was doing previously. No micro bevels. No jigs. No particular angle, even. And it came out just fine. Did the same with the strop, just pulling the blade. Sharpening is actually quite easy and not nearly as complicated as people make it, I think!

I will say that I think the fast cutting action of diamonds really helps, because you don't have to stay as consistent for as long, and you can quickly work out any "mistakes," or, rather, they work themselves out (when, say, you go at more acute an angle on a particular stroke than you'd like).