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A little closer look at jean stropping blades (SEM Comparison)

I was asked to take a look at a blade that had been used and stropped (on denim) under the SEM. This morning, before my workday started, I jumped on the microscope and ran the experiment. The blade used was a Personna Lab Blue that had 4 shaves under it's belt.

So here's a quick reminder what a Personna Lab looks like new:

Lab is on the right (the other is a Med):







New Lab edge:





So what's a used lab blue look like?

Used Blade Profile View:







Used Blade Edge View:





So that was fun, now the question, what does stropping do to a blade? The following images are of a blade that was stropped 20 times on each side, in turns of 5.

Stropped Blade Profile View:







Stropped Blade Edge View:





So have we learned anything?

I believe I can see a difference in the blade that was stropped versus not. It's very hard to tell the edge views, but the side profiles view shows me that jean stropping does in fact polish the blade edge, but it also creates a rough looking edge bur. I'm sure that the bur is gone on the first shaving stroke, but it does look a little scary.

Will stropping prolong a blades lifespan, maybe. I does appear to mechanically change the edge of the blade, but for the better? Who knows, let your face decide.

The one caveat to my test is that I didn't strop the blade in-between each shave, I only did it for the sake of this investigation. Doing it in-between each shave may work better, but maybe not, again YMMV.

Enjoy!
 
Interesting stuff, thanks. So the "used" shots are after four shaves, and the "used stropped" are the same blade after 20 strokes of jeans-stropping? Did the blade stay in the razor for the stropping, or did you take it out?
 
Interesting stuff, thanks. So the "used" shots are after four shaves, and the "used stropped" are the same blade after 20 strokes of jeans-stropping? Did the blade stay in the razor for the stropping, or did you take it out?
1. Yes
2. Blade was pulled from the razor to strop
 
I am lazy, so I leave the blade in the razor when stropping. That means that I am only stropping one side, and using roughly the same angle that I shave with. I strop three strokes per edge, and looking through an optical scope that seems to be enough to clear most of the residue. Any or all of those differences might change how the stropping affects the edge, but my intent is just to clean off any gunk.

This week I have been experimenting with jeans-stropping after every other shave instead of after every shave. As usual I am keeping the blade in the razor, and putting three reverse strokes on each side. Reducing the frequency of stropping is meant to fit in with the theory I outlined at http://badgerandblade.com/vb/showth...blades-(SEM-Comparison)?p=5931470#post5931470. Optical magnification suggests that it takes a couple of days for the soap residue to get bad (YMMV depending on hard water, product, etc.) and I figure jeans-stropping has some negative effect on the antifriction coating too. The idea is that I might be able to extend blade life even more by optimizing the frequency of stropping. Maybe every other shave will be often enough to keep the soap residue off, but not often enough to wear out the coating or damage the edge. Anyway I plan to keep that up over the next few weeks, trying different blades and soaps.
 
It may be a different part of the blade edge, but to me, the used stropped blade looks like the edge has chipped in several places. I don't see that on the un-stropped blade.

Also interesting, I don't see any edge deformation on the used blades like I would have expected (and like I did see on the voskhod in your other thread). My biggest curiosity was to see if stropping would clean those up.
 
The denim-stropping used 20 per edge, if I understand correctly. I use three, so it might take me six or seven stroppings to get the edge to that state. That leaves aside any difference caused by removing the blade vs. leaving it in the razor. Anyway 6-8 shaves that is about where I usually toss a blade, so in practice that edge deformation may not matter for me.

There might be something to the idea that we discard blades for different reasons, even when the symptoms are similar. A rough shave and skin irritation could be due to gunk sticking to the blade, or edge damage from use, or edge damage from stropping, or worn-out antifriction coating, or even a recurrent skin self-infection persisted on the blade. This would also mean that tricks like jeans-stropping may work for one person and not for another. YMMV indeed.
 
It may be a different part of the blade edge, but to me, the used stropped blade looks like the edge has chipped in several places. I don't see that on the un-stropped blade.

Also interesting, I don't see any edge deformation on the used blades like I would have expected (and like I did see on the voskhod in your other thread). My biggest curiosity was to see if stropping would clean those up.
I think what we're seeing is a really thin burr being formed at the edge of the blade. I went overboard on the stropping on purpose, more to see if would could actually see a difference in the blade edge.

My question was, would denim be a tough enough material to mechanically changer the blade edge, and I think we proved that it did. Like mblakele pointed out, if you were to do this as a everyday practice, you wouldn't strop so heavily and you'd do it after each shave.

I'm going to have to repeat this experiment at some point with a higher degree of control. I will try stropping after each shave and less times to better mimic what normal users do then take a look at the results under the mic.
 
Did my own mini-test to see how the stropping would impact the shave. Used a feather blade that had 3 full face shaves. Stropped one side, did not strop the other. Tried to shave. OUCH! Got crazy tugging on the stropped side, un-stropped felt much smoother. Tried a different angle for stropping the blade, same results. This is the second blade I've tried this on, so while not statistically indisputable, a trend is developing.

Evil4blue: As you stated, your face will tell you if stropping is a good idea or not. Mine says no.
 
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