Why razor blades get dull so quickly.

Some of you may have seen this recent study, but I found a cool video of some close up shaving action and I thought I’d share it. 

Here’s a story about the study: https://news.mit.edu/2020/why-shaving-dulls-razors-0806

Define "so quickly". Some claim to get 100+ shaves, but I am not in that group.

For sure I toss mine after 3 shaves, but if someone else wants to do 100+ shave that’s cool with me.

This study and video is amazing to me. You can actually see the blade “dulling” in real time in just a few passes. This experiment helps to address the question of how hair, 50x softer than steel, could physically deform/dull a blade. The unique insight here is that hair doesn’t dull a blade, it causes chips to the edge. The chips result from micro fractures caused by Martensitic hardening. The researchers hope to develop an alternative hardened steel with a homogeneous structure that would resist the dulling chips.

For sure I toss mine after 3 shaves, but if someone else wants to do 100+ shave that’s cool with me.

This study and video is amazing to me. You can actually see the blade “dulling” in real time in just a few passes. This experiment helps to address the question of how hair, 50x softer than steel, could physically deform/dull a blade. The unique insight here is that hair doesn’t dull a blade, it causes chips to the edge. The chips result from micro fractures caused by Martensitic hardening. The researchers hope to develop an alternative hardened steel with a homogeneous structure that would resist the dulling chips.

And this will happen to the inventor by Gillette!! 


https://www.youtube.com/watch?v=BcArJEYvaHw

I've never believed the micro chipping, corrosion theories because my blade usage tends to vary depending on where I am.

I've always noticed that hard water areas reduce my blade usage life considerably.

At home, tap water is medium hard and my Polsilver lasts 7-10 shaves. Sometimes even more!

At my in-laws, the water is one step away from coming out as a solid!...I get hardly 4 uses from Polsilver.

At my sister in law's place, the water is just a little harder than home and I get around 7 uses per blade.

I came across this study that discusses mineral build-up on the blade edge, causing it to blunt. I truly feel this is the most likely culprit because I can't see any other reason of how blade life would vary in different locations given my stubble growth and products remain constant!

https://knifesteelnerds.com/2021/01/11/w...s-to-dull/

Apparently, beard hair has a tensile strength similar to copper wire of similar diameter. It is possible to cut thin copper wire with a knife, but if you have ever tried cutting heavy copper wire with a knife, you will quickly discover that the knife gets dull. Some people have beards whose hairs are fine like thin copper wire. Others have beards whose hairs are much coarser. Some factors related to coarseness are nationality, hair color, and age. Many people with coarse beards are doing well if they get 3-4 shaves from a blade while others can get several dozen, maybe even 100+.

Another factor is the sensitivity of the shaver's skin. As the blade wears, it may not wear uniformly. That can make the edge rough. For those with sensitive skin, it may be the roughness of the blade that limits the lifespan. For those with less sensitive skin, as long as they blade is sharp enough to cut through their beard, their face does not mind.

I have a coarse beard (old man, white hair). I also have very sensitive skin. Although Feather Hi Stainless blades are super sharp out of the wrapper, the edge is not very durable. Thus, after a couple of shaves, the blade feels so rough on my face that I have to stop using it. With most blades, I can get 3-4 good shaves, but seldom more. I change out the blade whenever it no longer cuts my beard cleanly and begins to tub.or it starts to feel rough on my face.

I do find that the thicker Single Edge blades tend to last longer, but they are also more expensive, so the blade cost per shave is similar.

Since your beard and your skin may not be like others, the blade life others achieve is unimportant for you. Find blades that give you great shaves in your razors. When the blade no longer provides a great shave, it is time to replace it, whether that is 2 days or 100 days.

I’m into kitchen knives and whetstone sharpening.

Once I learned about the importance of honing a blade I began to be able to get far more shaves out of a blade.

I now shave with Fusion 5, Mach 3 and DE blades.

Before my wet shaving journey started in 2011, I would get 4-6 good shaves from a Fusion 5 cart, then toss it out.

After I sold all myDE razors in 2016 and went back to carts, I now all of a sudden got 30-40-50 great shaves from one Fusion 5 cartridge.

I tried stropping a DE blade with my thumb and on a razorpitt honing device and was able to get 50+ good shaves from a single Polsilver blade.

After learning the importance of stropping a blade and keeping it dry and clean, I understood why I all of a sudden could get drastically more shaves out of one blade.

My wife uses kitchen knives without ever honing them beforehand.
The softer steel knives will get dull after 10-15 uses
I hone my knives every single time before using them and I practically can go for half a year without needing to actually sharpening my kitchen knives.

I find the same applies to razor blades.

I now thumb strop my carts and DE blades before, during and after the shave, and I can get many great shaves from one blade.

As soon as I forget to do the stropping, the blades get dull fast within 2-3 shaves.

Very interesting.
Thanks for posting this.

I hate to state the obvious but let's keep in mind the green elephant in the room: $. Back in the day, Gillette's magnificent razors were very inexpensive because the money was made on consumables, namely, blades and, later, shaving cream. Nothing's changed. The idea of reducing one's income is a strong disincentive to designing blades that last and last. Bravo to guys like CHSeifert, who discovered ways to prolong a blade's life. In the 1970s, when the Age of Aquarius was still in the air, some recommended keeping blades in a container shaped like a pyramid. 

Keeping your blade under a pyramid actually does prolong the keenness of the edge, but only if the pyramid is aligned to true north and you are not surrounded by concrete and re-bar.  It worked in my single story shake roofed house, but not in my high-rise apartment.  And the Age of Aquarius began last December 28.