The promise is alluring, especially with those little Mach 3 heads going for as much as three bucks a pop, each package taunting with the tag line: "Fresh blade. Better shave. There is some truth to that. And there's also some truth to the scene in Alas, Babylon , the post-nuclear-apocalypse novel from the seventies, in which a protagonist shaves his face with a hunting knife.
It's uncomfortable, and his daughter laughs, but it works. Same goes for a blade sharpened by the silicon-carbide wheel in the Save A Blade. As we learned when we reviewed the Samurai Shark , silicon carbide shears away steel, and at the right angle, will give it an edge. But when you're sharpening a chisel, for instance, the measure of the tool's quality is its ability to hold a keen edge—any tool will get sharp for a moment, but good ones stay that way.
These blades are designed to be disposable and thus to lose their edge after a few uses. Tasan says razor blades are made of martensitic steels, some of the toughest materials known to mankind. Martensitic steel named for a 19th-century German metallurgist is a super-hard alloy, honed through heat and tempering, that is used in commercial razors, surgical instruments, ball bearings, and bicycle disc brakes. What Tasan and his colleagues found is that, despite this strength, the blades fatigued rather quickly after multiple shaves.
Tasan and graduate student Gianluca Roscioli devised an experiment to examine the progress of wear and tear on a blade after each shave. After examining several different commercial razors, the team found that they all were made from a similar hardened steel-carbide alloy. Because the materials were similar, the experiment used only one brand of razor. Roscioli shaved every three days for a month with the same razor, then brought it into the Cambridge lab.
This video shows how the tiny chips form in the blade after slicing through human hair. Our razor blades. Morten took these three test subjects and moulded them into a hard material. Then cut the razor blades in half because we wanted a microsopic view of the blade edge.
After only 30 days of working with the idea, we found the real problem! There was a coating on the razor blade edges. Something was sticking to the edge of the blades and causing it to become thicker and thereby dull.
But it also led to the next challenge. Were we able to restore the blade edge and make it sharp again? We tried brainstorming. We listed all the materials we could think of that had some sort of cleaning or sharpening ability.
You would not believe how many things, materials and liquids we looked into. After spending many days and nights evaluating different cleaning and sharpening materials.
We had more than 40 different materials on the list. We went through the list to find the best bets. This resulted in a list of five different cleaning and sharpening aids. Our aim from there was to test every single material to see which would perform the best. To put it mildly this idea failed miserably. None of the materials worked, and in fact some of them made the problem worse. Back to the drawing board, and to brainstorming. It came from a band-aid! Yes, a band-aid! We all know that when you remove a band.
Normally you just remove it using your finger and the friction of the skin. This were our answer. If you are able to remove the plaster from your skin by using friction, you might also be able to remove the coating from a razor blade using friction?
Now we were close. We had a problem and a plausible solution. We just needed to find the right material to sharpen razorblades by wiping off the residue from the blade edges. Knowing that the friction levels were the key, we started testing on a mild sandpaper, and to say the least, that was the wrong way to go. From there we moved on to rubber. Rubber could be made with the softness needed for the blades to come into close contact and create friction. Though it turned out we could not find a rubber material with a high enough friction level.
We then moved to thermo-plastic elastomer, which is a sort of silicone with a very high level of friction and a high level of softness. The feeling was incredible when all of the five test people called up 30 days later and were using the same razor blade.
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