Science Reveals the Secret to Making Your Razor Last

Photograph by Brent Murray Close

Photograph by Brent Murray

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Photograph by Brent Murray

Time and tide wear away all things, even when the thing is a metal razor and the tide is in your bathroom sink. Every razor grows dull. It'll happen any way you cut it, whether every day or the U.S. average of 4.3 shaves a week. At $3 or more for a stainless steel cartridge, the question is how to forestall that moment.

"Keeping a blade dry matters," says Robert Ambrosi, the owner of Ambrosi Cutlery, a business that sharpens the knives of many of New York City's commercial kitchens. "And razor blades are thin, which makes them even more susceptible to corrosion."

"If we were to take our razor blades and dry them off every time we use them," says Thomas Eagar, professor of materials engineering at MIT's department of materials science and engineering, "they would probably stay sharp for six months." Raising the bar even further, Eagar says that "If I were to rinse my razor with clean water and then dry it off with a hair dryer after that, it would probably last a year."

Why the emphasis on keeping the razor clean? It's not as if sustained contact with your cheek is toxic enough to eat away metal....right?

Wrong. "Metallurgists say stainless steel isn't stain-free, it's stain-less," Eagar says. "It will corrode, particularly in a chloride or salt environment." And guess what? "The human skin is very salty," Eagar says. That's right: your cheeks are a menace.

You might pause here to consider the other stainless steel in your life -- your stove top, dinnerware, or blender. You don't dry those off with a hairdryer, and yet they seem to be managing just fine. "Razor blade steel can be hardened just as hard as a nail file, and that helps it keep a sharp edge," says Eagar. "But that kind of stainless steel isn't as corrosion-resistant as what they make your dinnerware out of. If you want to make it hard, you give up some of its resiliency." Which means a superfine shave is coming at the expense of multiple decent shaves in the future.

It explains the momentary silkiness of the first few days of a new razor. And it also explains the precipitous drop-off just a few days later, where it suddenly feels as if you're trying to shave with steel wool.

"No matter how hard or sharp the edge is," says Ambrosi,"it's going to get dull. And when it gets dull, it gets really, really dull."

Want to minimize the number of $31.49 packages of cartridges you go through? If you've been switching your razor every two weeks, follow Eagar's advice and you've saved yourself $95 a year. Just remember that air and water are your friends, and they're free.

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