Why razors 'skip', a reason to season your razor.
How many times have you had it happen? You're shaving along nicely, you run out of lather and suddenly the head of your razor is no longer sliding along smoothly, now it's gripping your skin and making it feel like you're dragging rubber across it.
I have a good theory as to why it happens. I should state for the record that I have a degree in engineering, (in biochemical engineering while we're being honest) so I'm not talking entirely out of my *** when I state my theory as to why a razor will skip across your skin like that.
The effect that soap has on water it to break the surface effect. Think of what happens to a bug that is walking on water, it's the surface effect that is keeping the water from parting from under it's feet, so therefore it doesn't sink. But if you were to add soap to that water, the surface effect breaks down and the bug will fall into the water and drown. The same effect for you would be to be walking along a sand dune and suddenly the sand dune would have the consistency of liquid mud and you would just fall in.
But, in the words of Peter Griffin 'I digest'.
What is happening with your skipping razor is that you no longer have enough soap on that part of your skin to break the surface effect of the water. Now that surface effect is back into play in the equation and the force that keeps water molecules from being pried apart is back in full force. What is happening is that the water itself is in such a small space that it's not literally just two surfaces of water in touch with each side of the non-existent gap between your skin and the head of the razor.
To put this into a context that you all probably already understand to some extent, the same thing happens when you get a double edged razor blade wet and set it on a non-porous flat surface. It'll stick, and it'll stick tight enough that you're probably going to be really careful about not prying it up by the blade using the sharp side because you know that suddenly it's going to pop up off that surface, and that is the magnitude of the force that is acting upon your razor.
This isn't a force that you need to imagine in your heads or ponder, you can go to into your very own bathroom and grab one of the things in your massive array of shaving gear that you don't need and pull out a double edge blade, and I know you have one available because you've read this far about this topic, you're actually interested. You don't have an excuse to take my word for it, you can prove this argument for yourself.
Back to the situation I mentioned at the very beginning, you pull the razor across your skin and you feel it chatter across the surface without the blade doing much of anything. While you're in the bathroom proving to yourself that I'm not entirely full of crap you can try the next experiment as well.
I mentioned earlier that the force is the result of an amount of water that is equal to what amounts to only two surfaces of water. So while you're doing the experiment with your razorblade, you may discover if you play around, that the more water past a certain point, the easier it is to move the blade. Placed in a small puddle the blade will mover around easily, but if you slide the blade out of the puddle and keeping it moving you will feel the resistance to movement begin to mount the further you go, eventually the blade will stop being able to slide forward and at this point try and pop that blade up and realize just how strong the force we're talking about, is.
Now imagine that the blade is moving across skin, which unlike the counter in your bathroom is an elastic substance and not immovable, by an outside force that far outpowers the force of surface tension and that you now understand full well because you did the experiment.
As the blade is dragged along the counter made from skin, the cushion of water under the blade will get smaller and smaller as the razor wets the skin in it's wake and depletes the amount of water under the razor. Eventually the water runs out and all you have are the two surfaces of water that stick to both the surface of the skin and the razor blade that is sliding across it.
Now, it should be mentioned at this point that from the perspective of fluid dynamics, the very first layer of water molecules that wet a surface CANNOT move in any form of flow. Therefore when you have two immovable surfaces of water in contact, they will hold together until a force like that which you felt yourself is applied to break the double surface tension.
But... by this time you've achieved the double surface tension force and it has stretched the skin because skin is elastic under that kind of force. When surface tension finally breaks, the skin snaps back to where it got dragged there from and the razor blade is now loose. If the spot where the razor blade landed was wet as the puddle it came from though, the process could start again. And this is exactly what is going on across your face when your razor skips and is in effect hopping across your skin.
Now how can we fix the problem? Well, one obvious answer is to use more product, be it either re-lathering or dabbing a bit of soap on the head of your razor. If you put down more soap then the surface tension is gone again and you may resume shaving, skip-free.
The other answer though, is to season your razor. And by season I mean exactly in the way you season cast iron. You grease it up, bake it, grease it up, bake it. You have to establish a coating of soap on the head of your razor so that it repels water, and you have to keep it there. (In fact this is exactly the same reason that properly seasoned cast iron is pretty much non-stick, because it doesn't get wet.)
I know this may sound like heresy to all you sufferers of RAD who like your shiny chromed handles to sparkle and look flawless at all times, or you may want your fatboy quadruple replated to make it look like the chrome job on a car. But, guys, your cleaning effort is squandered when it comes to the quality of your shave.
A seasoned razor, on the other hand, has a layer of soap scum built up. And for those of you who aren't religious about cleaning out your sink, you know what I'm talking about, those spots that you throw water on and they don't get wet. This is what makes a less than clean razor shave smoother than a shiny one because you've cut the surface tension of the water in half or even more. Soap on the head of your razor which isn't going anywhere quickly is going to cut down on surface tension and make gliding the head of your razor across your face much smoother, even if there is no soap laid down previously.
So there you have it, a reason to not clean your razor. Or, again with the cast iron analogy, a reason not to do too good a job cleaning your razor, you'll just have to start over to get back to smooth shaving the way it should be.
How many times have you had it happen? You're shaving along nicely, you run out of lather and suddenly the head of your razor is no longer sliding along smoothly, now it's gripping your skin and making it feel like you're dragging rubber across it.
I have a good theory as to why it happens. I should state for the record that I have a degree in engineering, (in biochemical engineering while we're being honest) so I'm not talking entirely out of my *** when I state my theory as to why a razor will skip across your skin like that.
The effect that soap has on water it to break the surface effect. Think of what happens to a bug that is walking on water, it's the surface effect that is keeping the water from parting from under it's feet, so therefore it doesn't sink. But if you were to add soap to that water, the surface effect breaks down and the bug will fall into the water and drown. The same effect for you would be to be walking along a sand dune and suddenly the sand dune would have the consistency of liquid mud and you would just fall in.
But, in the words of Peter Griffin 'I digest'.
What is happening with your skipping razor is that you no longer have enough soap on that part of your skin to break the surface effect of the water. Now that surface effect is back into play in the equation and the force that keeps water molecules from being pried apart is back in full force. What is happening is that the water itself is in such a small space that it's not literally just two surfaces of water in touch with each side of the non-existent gap between your skin and the head of the razor.
To put this into a context that you all probably already understand to some extent, the same thing happens when you get a double edged razor blade wet and set it on a non-porous flat surface. It'll stick, and it'll stick tight enough that you're probably going to be really careful about not prying it up by the blade using the sharp side because you know that suddenly it's going to pop up off that surface, and that is the magnitude of the force that is acting upon your razor.
This isn't a force that you need to imagine in your heads or ponder, you can go to into your very own bathroom and grab one of the things in your massive array of shaving gear that you don't need and pull out a double edge blade, and I know you have one available because you've read this far about this topic, you're actually interested. You don't have an excuse to take my word for it, you can prove this argument for yourself.
Back to the situation I mentioned at the very beginning, you pull the razor across your skin and you feel it chatter across the surface without the blade doing much of anything. While you're in the bathroom proving to yourself that I'm not entirely full of crap you can try the next experiment as well.
I mentioned earlier that the force is the result of an amount of water that is equal to what amounts to only two surfaces of water. So while you're doing the experiment with your razorblade, you may discover if you play around, that the more water past a certain point, the easier it is to move the blade. Placed in a small puddle the blade will mover around easily, but if you slide the blade out of the puddle and keeping it moving you will feel the resistance to movement begin to mount the further you go, eventually the blade will stop being able to slide forward and at this point try and pop that blade up and realize just how strong the force we're talking about, is.
Now imagine that the blade is moving across skin, which unlike the counter in your bathroom is an elastic substance and not immovable, by an outside force that far outpowers the force of surface tension and that you now understand full well because you did the experiment.
As the blade is dragged along the counter made from skin, the cushion of water under the blade will get smaller and smaller as the razor wets the skin in it's wake and depletes the amount of water under the razor. Eventually the water runs out and all you have are the two surfaces of water that stick to both the surface of the skin and the razor blade that is sliding across it.
Now, it should be mentioned at this point that from the perspective of fluid dynamics, the very first layer of water molecules that wet a surface CANNOT move in any form of flow. Therefore when you have two immovable surfaces of water in contact, they will hold together until a force like that which you felt yourself is applied to break the double surface tension.
But... by this time you've achieved the double surface tension force and it has stretched the skin because skin is elastic under that kind of force. When surface tension finally breaks, the skin snaps back to where it got dragged there from and the razor blade is now loose. If the spot where the razor blade landed was wet as the puddle it came from though, the process could start again. And this is exactly what is going on across your face when your razor skips and is in effect hopping across your skin.
Now how can we fix the problem? Well, one obvious answer is to use more product, be it either re-lathering or dabbing a bit of soap on the head of your razor. If you put down more soap then the surface tension is gone again and you may resume shaving, skip-free.
The other answer though, is to season your razor. And by season I mean exactly in the way you season cast iron. You grease it up, bake it, grease it up, bake it. You have to establish a coating of soap on the head of your razor so that it repels water, and you have to keep it there. (In fact this is exactly the same reason that properly seasoned cast iron is pretty much non-stick, because it doesn't get wet.)
I know this may sound like heresy to all you sufferers of RAD who like your shiny chromed handles to sparkle and look flawless at all times, or you may want your fatboy quadruple replated to make it look like the chrome job on a car. But, guys, your cleaning effort is squandered when it comes to the quality of your shave.
A seasoned razor, on the other hand, has a layer of soap scum built up. And for those of you who aren't religious about cleaning out your sink, you know what I'm talking about, those spots that you throw water on and they don't get wet. This is what makes a less than clean razor shave smoother than a shiny one because you've cut the surface tension of the water in half or even more. Soap on the head of your razor which isn't going anywhere quickly is going to cut down on surface tension and make gliding the head of your razor across your face much smoother, even if there is no soap laid down previously.
So there you have it, a reason to not clean your razor. Or, again with the cast iron analogy, a reason not to do too good a job cleaning your razor, you'll just have to start over to get back to smooth shaving the way it should be.
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