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What Causes Razor Blades to Dull

Interesting article here:


This was written by a guest author ( John Verhoeven) on Larrin Thomas' web page. Larrin is a PhD Mettalurgist who as a side hobby delves deep into blade steels (and is the son of Devin Thomas, the now-retired maker of premium damascus steel used by makers such as Chris Reeve).
 
Thanks for posting that. Too funny, some people here will start drying their blades and cleaning their razors, after all the debate... and eye-rolling. Including the one that compared taking a razor apart after every shave with cleaning the engine after every trip.
Oh well...
 
What I get from a cursory reading of the cited article is this: The one thing most shavers don't do, but should do especially if they have hard water, is to remove the blade after shaving and gently blot it dry it with a towel. Later, when everything is bone dry, reassemble the razor for the next shave. Keep the blade dry until the next shave. Did I read this correctly?

I think cleaning the razor's head and handle after every shave is overkill; cleaning the razor once a week when the blade is changed will suffice.
 
And then there will be those who enjoyed the article, understand the matter, and still just rinse the razor and leave it on the counter.
True. I normally rinse with hot water and wipe with a towel (strop style), but I don't disassemble the razor to completely dry both sides of the edge, and I don't intend to change this practice. I figure that handling the blade that often risks damaging the fine edge as much as not drying it. I normally get 21 shaves from a blade, sometimes 28.
 
Looks like I'm doing something right. I've always patted the razor dry before storing it in the razor.
 
It is basically a problem with limescale, namely soap scum and mineral deposits such as calcium carbonate, you do not want that on your bathroom surfaces and you definitely do not want that on the edge of your razor blade.

Although it is not very important to me to extend blade life (they are very cheap), I have tried once or twice in the past to palm strop the blade after letting it soak for a couple of minutes in vinegar, which made the blade feel more crisp.
 
Only did the dry towel routine with feather fhs to use it for 2 maybe 3 days instead of 1-2.
But with my broman uh just rinse and it is more than ok for a week (2 if you count that 1 shave with half de a week)
 
I use a Razorpit and I usually get about two weeks out of a cartridge. The blades don't get dramatically dull quickly, they just slowly fall off in effectiveness.

I'm going to have to try cleaning my cartridges better, and see if they last longer. Getting a month out of a cartridge would be nice.
 
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I have always disassembled the razor and rinsed every component in hot water, and then dried and reassembled the razor, making it ready for the next shave. I heard this information on Clark Howard’s radio program a few years ago.

I’m a daily two pass shaver, shaving 5 to 7 times each week. I typically get between 30-35 shaves from a Feather blade using this procedure.
 
I have always disassembled the razor and rinsed every component in hot water, and then dried and reassembled the razor, making it ready for the next shave.
^^ same

And I clean it with toothpaste and a toothbrush

And I wipe off the blade edge 4-5 times with my thumbs.

I’m a daily two pass shaver, shaving 5 to 7 times each week. I typically get between 30-35 shaves from a Feather blade using this procedure.
Thats amazing. I ran out trying to get more than 2 shaves per blade.
 
I have always disassembled the razor and rinsed every component in hot water, and then dried and reassembled the razor, making it ready for the next shave. I heard this information on Clark Howard’s radio program a few years ago.

I’m a daily two pass shaver, shaving 5 to 7 times each week. I typically get between 30-35 shaves from a Feather blade using this procedure.
I can relate to that. Using a Feather half-blade in my shavette, I give it 6 to 8 light laps on a clean chamois strop after each use. This has increased the blade life by 4 to 5 times.
 
I am no expert at all but I have so many issues with this article. I agree drying a blade does prevent corrosion, I've worked with high carbon knives a lot, they quickly rust if let wet. Absolutely drying any blade will help to preserve it.

However...

1) We don't know the diameter of the gentleman's facial hair or it's toughness, density/spareness, growth rate. Also it's mostly his perception of "smoothness". I see a lot of men who could use almost a "butter knife" to cut their facial hair relative to other men with coarse hair.

2) He used a 3 blades system. I am certain that double edge razor blades are of different compositions. It is evident that DE blades are less corrosive resistant and are prone to rust and corrosion far quicker. DE blades have much less of the composites that prevent corrosion like chromium, vanadium and molybdenum, or whatever composition DE blades have in them.

3) Doesn't mention how specifically carbonates dry to affect dulling. Although I assume it causes increased corrosion. I would have liked examinations and photos of these carbonates causes dullness over time on specific types of razors and their metal composition specified.

4) Doesn't mention DE metal composition, blade coatings, metal hardness of DE, blade thickness, edge geometry, blade stiffness/support, cutting angle. This affects edge retention greatly. I sharpen knives by hand... https://core.ac.uk/download/pdf/44290183.pdf

5) Microchipping and edge retention.... edges can chip, they can roll... it greatly depends on the metal. High carbon steel like shirogami (white-paper) can have larger carbon particles and although super sharp, it does not retain its edge, but it doesn't roll either. Drop this knife and it shatters, it also rusts super quickly and must be kept dry. I know knife makers are concerned with edge retention, toughness abrasion resistance, sharpen-ability, corrosion resistance... Elmax steel is highly regarded for this.

My point being this... DE blades are more akin to higher carbon simpler steel and a mach 3 is something like an elmax steel. My guess is that DE razors certainly would suffer far more microchipping than the mach 3.

I would love to have a knife maker's view on this.
 
Oh another thing... he quotes the use of DE razors e.g. last about 5 days WTG, ATG and XTG... then uses a multi-blade system... different kettle of fish completely!!!! I was actually astonished by this.
 
A few years ago, I ran a drying and stropping test on a Sensor Excel cartridge. At that time I was required to shave daily for work, so I was shaving five times a week plus once on Sunday for church. The resul was the cartridge lasted for a year before it go so dull that I retired it. I figure that’s well over 300 shaves. I dried the cartridge and stropped the side of the blades that I could get to after every shave.

As I said earlier, I’ve tried this on a Feather blade and gotten 30-35 two pass shaves with it before I binned it.

Of course I have no idea how to compare my beard density and strength. I can only say that I am 68 and my beard is mostly white. When I grew a beard in my 30’s, it was very dense and very black, so I would think it was course. Does a beard become softer when it loses its pigment? I would say it does, but how does that affect the blade?
 
Disassembling the razor each shave will probably increase the number of times I drop parts on the floor or into the sink. I wonder if the expectation value of that procedure is positive, given the impact on tolerances, blade alignment, dents (not all my razors are stainless steel), galling et.c.

I normally disassemble my razor once /week. Doing it daily is aging the razor 7 years /year.
 
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