Is stropping really harmful for edge retention?

T

Threethreethree

Joined
May 30, 2013
Messages
117
Yo guys,
I read somewhere that stropping cause burnishing and lot of fatigue and thus reduced the life span of an edge and may cause rolls and chips.
Is that true ? Can you avoid partially this effect if you use a clean strop each time ?
I feel quite concerned about it as i strop a lot, and only use stones / sandpaper when i really need to.
 
The problem with stropping is that many people go and make their ownout of old belts or whatever bits of scrap they have laying around. This is bad because

a) the leather is much to thick and soft to make an effective strop. it simply wraps over the edge and rounds it off.

B) if its used material or something buddy has just laying around his shop or wherever. Theres little bits of god knows what (small bits of gravel or whatever) They are difficult to remove and can chip out the edge as you strop.
 
Well the reason im worrying about it is because the guy seemed to know what he was talking about, however i know hes banned from here because of some stubborn trollish attitude (Cliff Stamp).
 
I had a guy on another forum tell me that stropping is bad because it creates so much friction that it messes up the heat treat of the edge. Don't believe everything that you read, try it both ways and just use whatever works best for you.
 
it's from the spyderco board's chipping cts-xhp thread, right? i read the whole thing and from a physics stand-point it makes sense regarding metal fatigue. and it wasn't just cliff stamp, a few others too made a well-reasoned analysis why.

what i've always done though is sharpened with bench stones or sandpaper or sharpmaker (depending on the knife or my mood) as sharp as i can make it and may or may not finish the process with a few passes with a strop. then every now and then i'll strop it to maintain it.

what i think those guys are saying is that stropping is not a replacement for "actual" sharpening. that is, several hundred passes with a strop with various compounds will produce a weaker edge compared to the same level of sharpness done with stones.

i'm not an expert on sharpening, but that's what i took away from reading that article and thinking about it from a physics standpoint.
 
It can be bad in the following ways:
-If the strop is over used and thus loaded with metal abraded off that metal will burnish and smear your edge and stress is (in the same way excessive steeling will...see John Juranitch).
-Strops are very easy to contaminate as you can't rinse them off...moving from 1 micron to .5 micron to .25 micron for example, and if you contaminate them you are not going to get a very uniform scratch pattern.
-With too much pressure or two soft of a medium, you can round over the edge, destroying it's slicing aggression
-Often times they are in high grits/low microns so people over use them, spending excessive amounts of time and strokes to bring and edge back which again stresses it and weakens it and increases the issues with the above mentioned things.
-They have to be used edge trailing which pulls the metal towards the apex and can exacerbate burr formation.

None of that means they can't be used with great success, but like with most things, it's useful to consider all aspects of the process if you can.
 
In a word, NO.

If done well, stropping is likely the best way to maintain a good working edge on a blade (if not excellent), and minimize unnecessary metal removal at the same time.

Stropping with poor technique (poor angle control, too-heavy pressure), or using too-aggressive compound unnecessarily, will do more harm than good. But, if one's technique is sound, and the compound or stropping substrate is well-selected for the needs of the edge, one can strop virtually all day without harming an edge. There will likely be some point at which the noticeable improvement in sharpness will slow or cease, however.

BTW, two of my favorite and BEST strops are old belts (sueded sides), used with green compound and also bare. One belt is relatively new, the other is one that my father wore while serving in the Army about 60 years ago. That leather is some wonderful stuff. Leather does not have to be new or pristine (or expensive, most importantly) to work excellently on an edge. Keeping it clean, within reason, is always good, but there's no significant advantage in getting 'obsessive' (this, coming from ME :D) about the cleanliness of it. Wipe it down between sharpening sessions, and also wipe down your blade after it's been on the stones or after using coarser grit compounds.

Stropping by hand won't heat a blade enough to damage it. Doing so on a powered leather wheel, as with any powered sharpener, very well might damage it, in inexperienced or careless hands.


David
 
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Ive asked many chefs why no one strops for sashimi knives/kitchen knives. It weakens the edge.

as a sushj chef, my edge needs to stay sharp at least 8 hours, microbevel is the way to go.

stroping works, but for razors and knives that are only for looks and showing off.
 
Obsessed with Edges said:
Stropping by hand won't heat a blade enough to damage it. Doing so on a powered leather wheel, as with any powered sharpener, very well might damage it, in inexperienced or careless hands.
Click to expand...

Thanks for pointing that out, you're right powered stropping is a whole different ball game.
 
I stopped stropping after the 4th session to maintain an edge, and now hone the edge on a fine stone after the 4th time. This has given me more life for my edges before resharpening is needed.

Stropping is not harmful per say but some people think it's the same as a sharpening and can be used as many times as one wants and for however long they want.
Stropping should be used to simply to align the edge back IF there is an edge to align. If you add abrasives to the mixture, then you are both aligning the edge, and finely honing/polishing the edge. However the abrasive aspect is a whole different ball game than "stropping". It just so happens doing both at the same time provides excellent and easy to do results.

I started limiting my self out of my own accord when I noticed after the 5th or 6th stropping session that the edge would not last no where near as long as before and tested worse than before after every stropping session. When I used my microscope after the 10th stropping session, I noticed tiny microscopic breaks in the edge, it appeared as if the metal had been ripped out. The edge was still "sharp" but microscopically I could see why it was dulling so quickly.

Take that for what you will.
 
The thing about stropping is, there's literally an infinite number of variables affecting how well it'll work. It's too easy and misleading to write off the technique as harmful, but that only comes from not working enough to figure out what works and when. The key is figuring out which variables to select, for a given desired edge finish and steel type. Knowing when to stop stropping with a particular compound is important as well. Some compounds will be too aggressive for a given steel, and can over-polish and dull an edge when taken too far (like diamond on 1095, or even silicon carbide on the same, and some AlOx compounds as well). This is why I've settled into using green compound and bare leather on my simple carbon and basic stainless blades (1095, CV, Opinel's XC90, 420HC, 440A, etc.). More often than not, a few passes on the green, and cleaning up on the bare leather accounts for 99% of the maintenance I do on these steels.

Using not-aggressive-enough compounds on very wear-resistant steels (S30V, etc.) will be counter-productive, because the compound won't abrade carbides (vanadium- and chromium carbides) effectively, and edges can't be made crisp with them. This also happens when the stropping substrate (leather) is too soft, and therefore doesn't give compound a secure foothold from which to work as aggressively.


David
 
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Sadden said:
The problem with stropping is that many people go and make their ownout of old belts or whatever bits of scrap they have laying around. This is bad because

a) the leather is much to thick and soft to make an effective strop. it simply wraps over the edge and rounds it off.

B) if its used material or something buddy has just laying around his shop or wherever. Theres little bits of god knows what (small bits of gravel or whatever) They are difficult to remove and can chip out the edge as you strop.
Click to expand...

You can use sub optimal leather and still get fantastic results. Especially if using a cutting medium.

I used a broken belt (although it was good quality leather to start). It is softer than dedicated strop leather, you just have to pay attention to technique. I get great results.

I keep meaning to upgrade, but have not.

The hair between the knives is for testing.



I'd say it works.



Easily shave curls off of a free hanging hair.

 
bld522 said:
I'll just leave this here: http://zknives.com/knives/articles/wssteeling.shtml
Click to expand...

This is actually very good information on this subject. I as well have noticed stropping on plain leather at times has little affect on the edge. Whereas stropping on a loaded, slurry strop, (this author calls it sharpening) does affect the edge in a positive way in short order. This I agree is a better method than steeling. Yet, I seldom see a loaded leather strop in a Butcher's shop. Done correctly I don't think stropping damages the edge much but refines it. DM
 
David Martin said:
This is actually very good information on this subject. I as well have noticed stropping on plain leather at times has little affect on the edge. Whereas stropping on a loaded, slurry strop, (this author calls it sharpening) does affect the edge in a positive way in short order. This I agree is a better method than steeling. Yet, I seldom see a loaded leather strop in a Butcher's shop. Done correctly I don't think stropping damages the edge much but refines it. DM
Click to expand...

a strop would get nasty fast at a meatcutter's shop. You can wash a steel.
 
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