Is stropping really an effective practice?

G

Guy McVer

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Mar 22, 2022
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I have often seen people saying that you can strop an edge back to life as if it was some kind of magic. As if the stropping was actually fixing the edge. But in my experience, I have noticed something different.

Edges can get clogged. Edges can accumulate dirt and gunk that will affect the cutting performance. Simply wiping the edge on a pants leg or a paper towel or a cloth is sufficient to clean the debris off. It works great after that.

The edge was merely dirty, and wiping it off returned it to normal. I have tested this extensively on magazine paper, newspaper, phone book pages, and receipt paper. An edge that will have problems giving a smooth uninterrupted cut often just needs a quick wipe-down. No stropping required. It can struggle and hang up during the cut, but simply wiping it clean will give you blissful cutting performance again.

I have long suspected that all of the people praising the virtues of stropping for edge maintenance were unwittingly just cleaning their edges off on the strop rather than actually restoring the edge. I think they may have been under a false impression of what the strop was doing.

What say you? I want to hear the benefits of your experiences. "Edumacate" me.
 
Before I forget, I also want to point out that this also applies to sharpening on stones or ceramics or diamond plates. The edge can be full of particles from the sharpening process. A simple wipe clean will remove them. I have experienced this from lots of testing with cutting materials. The use of a strop is not required.

Burr removal after sharpening is another matter, of course. But a ceramic hone can usually do the work of a strop, and without the convexing.

Diamond paste applied to a strop can of course further refine the edge, but only if the paste is finer than the sharpening implements you used prior to that.

Looking forward to hearing lots of real world experience from people on this. I want to know more.
 
Guy McVer said:
I have often seen people saying that you can strop an edge back to life as if it was some kind of magic. As if the stropping was actually fixing the edge. But in my experience, I have noticed something different.

Edges can get clogged. Edges can accumulate dirt and gunk that will affect the cutting performance. Simply wiping the edge on a pants leg or a paper towel or a cloth is sufficient to clean the debris off. It works great after that.

The edge was merely dirty, and wiping it off returned it to normal. I have tested this extensively on magazine paper, newspaper, phone book pages, and receipt paper. An edge that will have problems giving a smooth uninterrupted cut often just needs a quick wipe-down. No stropping required. It can struggle and hang up during the cut, but simply wiping it clean will give you blissful cutting performance again.

I have long suspected that all of the people praising the virtues of stropping for edge maintenance were unwittingly just cleaning their edges off on the strop rather than actually restoring the edge. I think they may have been under a false impression of what the strop was doing.

What say you? I want to hear the benefits of your experiences. "Edumacate" me.
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Maybe in some limited examples it may be as you say, but I don't think that's true most of the time. For example you can take a soft stainless kitchen knife and wash it all you like but it won't become sharper until you strop it. Stropping is pretty limited though. Your edge needs to be pretty good to start with.

At the end of the day even an unloaded leather strop has some small abrasive qualities. If your edge has some minor microscopic mushrooming on the apex a strop can improve keenness. A loaded strop will obviously be more effective. Arguably you would be better off just touching up an edge with a stone.
Guy McVer said:
Diamond paste applied to a strop can of course further refine the edge, but only if the paste is finer than the sharpening implements you used prior to that.
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Not necessarily. Stropping is gentler than a hard abrasive like a stone. The scratches are shallower. I believe you can absolutely refine an edge with a similar or even a bit coarser size abrasive on a strop.

This is just my opinion though.
 
Once you control for variables, then you will know if stropping matters in a given situation. In your testing, if you have not controlled for all the variables (which is to be fair, nearly impossible)
Another variable is the abrasive shape, in the world of straight razors there are several finishing stones that are quite desired which rated at "lower" grits than what many people hone to, but they change the character of the final edge in a desirable way, in combination with the second to last hone. For example, they find a difference between the finish coming from say a 10k and the finisher to a 20k and the same finisher.

Also you say "clogged" so is your edge cutting via microscopic serrations or final geometry. Again, that's a variable to control, I have a few knives that can get enough tape gunk on them to it impacting cutting performance, but only when they are nearing the time a sharpening is needed, so it's a few percentage points, if the edge is fresh, they can be gunked up totally and it's fine. And because I freehand like a peasant, a loaded strop corrects for my poor form in that final apex on the knives that need it. Some don't need it. Variables.
 
There is a site on the net with 4 very informative articles (with SEM images) describing in details the effects of stropping.
There are also some articles about a burr which include stropping.
 
No way it's just dirt. I carry tool steep blades so I generally give them a quick wipe on my pants if I got it dirty or wet, that never brings back anything.

I sharpen them to 32 degrees inclusive no microbevel. Off the stones they will shave easily, not push cut paper. Stropping then they will pushcut. I typically use it until it can't shave arm hair anymore then I'll hit it on a diamond strop and usually it'll come right back to shaving again. Not forever, kind of depends on the edge and what your using it for. Stropping will bring back a ever so slightly dull edge to sharp. But once it's too far gone stroppings useless. Then I just use the knife until I think it's unacceptablely dull then sharpen again.

I think of stropping as the finishing step of sharpening then as a maintenance step to stretch out how often I have to sharpen on the stones. But it's not a placebo at all. Definitely makes a difference. Cleaning my knife doesn't do the same thing.

The science of Sharp website theone45 mentioned is a wealth of information. I wish I had access to a microscope like that
 
I strop my blades if I'm going to be cutting into harder material. I don't strop a blade if I plan to use it for a lot of slicing. The polished edge seems to hold up for me better on things like zip ties and cardboard boxes. I like the toothy edge for slicing better. I'll be interested to see everyone's answers. There seems to be a lot of knowledge that's thrown around on this forum.
 
I'm slowly beginning to lean towards an anti-stropping position. I guess I've been either stropping too hard or for too long because it's thickening my edge... although I've never tried diamond compound.

Used to be about removing the bur for me but ever since I've been using harder steels it just doesn't have the same result. Leaning more towards a stone honed micro bevel these days.
 
The strop must be well loaded and the compound must mach the task, that is the steel and the condition of the edge.

I use Bark River white compound for normal steels and DMT Diapaste for supersteels. I think the main purpose of stropping is to remove every last bit of the burr and if it takes more than ten or so passes, then it is better to go back to stones or plates and work on the edge some more.
 
I never strop knives. Not during sharpening and not between sharpenings.
I believe it is over emphasized and often misunderstood in practice.
It is an unnecessary practice in my opinion.
I’m sorry to any who disagree and I don’t care enough to argue about it.
Tomorrow when I’m home again I’ll check this thread and maybe I can offer some of my reasons I feel the way I do.
Have a wonderful day.
 
I do tend to run a rough "working edge", or what a lot of people call "toothy". Maybe it's true that such an edge tends to pick up more tiny debris and hold on to it, thus requiring a wipe-off to maintain cutting performance. If this is true then it would reveal one of the benefits of having a more polished edge.
 
I'm no expert, but if you talk to people who do whittling, I think all they mostly do is strop their knives. I saw one video (can't remember which one) a while back where the gentleman said he never puts his whittling knives on any kind of a stone. Wood carvers use a strop, leather workers, barbers, etc. So I think stropping must be doing something to refine the edge of the blade. More than simply cleaning it. I suspect it does, anyway.
 
Each of my Krein regrinds has only required gentle stropping, whether loaded or not, to restore its razor sharpness. The impact of polishing an edge is more significant than one might assume. However, a heavily used knife will inevitably require stones or diamonds to remove any imperfections from the edge.
 
I wish I had more input, but I would like to make a point that I appreciate the thread.💪
 
Hell Yes it works! Look up, Master blade Smith Jerry Fisk. A living legend! He Strops on his Jean pant leg & on his hand… It removes all burr & polishes your edge. Put a cardboard backing from a writing pad on a 12” x 6” piece of glass or any hard level surface & you can see the metal removed darken the cardboard. There is clay in cardboard…
 
RHINOKNIVES said:
Hell Yes it works! Look up, Master blade Smith Jerry Fisk. A living legend! He Strops on his Jean pant leg & on his hand… It removes all burr & polishes your edge. Put a cardboard backing from a writing pad on a 12” x 6” piece of glass or any hard level surface & you can see the metal removed darken the cardboard. There is clay in cardboard…
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I have sometimes used the palm of my hand to wipe off my edge in a stropping motion, but I find that a pants leg usually works better.

I have a feeling this might ultimately come down to semantics. What is stropping precisely, and what's the difference between stropping and wiping the edge clean, etc. When and where might they overlap. On the microscopic level, wiping an edge off could be removing tiny amounts of steel. But this should be negligible.
 
Guy McVer said:
I have sometimes used the palm of my hand to wipe off my edge in a stropping motion, but I find that a pants leg usually works better.

I have a feeling this might ultimately come down to semantics. What is stropping precisely, and what's the difference between stropping and wiping the edge clean, etc. When and where might they overlap. On the microscopic level, wiping an edge off could be removing tiny amounts of steel. But this should be negligible.
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Stropping is a trailing edge motion on a slightly abrasive surface to remove a burr & polish a cutting edge. Paper, cardboard, cotton etc materials will polish & I add Green Chrome buffing compound.
 
Gunk on your edge will certainly affect cutting performance, but stropping is about a lot more than that. There are different reasons to strop:

1. Deburr and refine the edge after sharpening;
2. Bring back performance of a worn (but not completely shot) edge; or
3. Polish edge bevels for aesthetic reasons.

You can absolutely strop back an edge that's been used to, for example, cut up a bunch of cardboard. If you have the right compounds and strops, you can bring back a knife that struggles to slice paper to hair whittling sharp.
 
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