DrySyllabub2563 OP t1_j2dg7gi wrote on December 31, 2022 at 12:55 PM

Reply to comment by [deleted] in ELI5: What makes the rust on a rusty nail different from the rust on shaving razors to where one needs an immediate tetanus shot and the other happens daily by DrySyllabub2563

My understanding was that razors go dull due to micro rusting that happens from the wet/dry cycle since your can’t get them ever fully dry.

Could be wrong on that though and my whole understanding of razors is 🤯

Berek2501 t1_j2dhqf1 wrote on December 31, 2022 at 1:11 PM

No, razors go dull because the hairs will wear down the sharp edge, making it more blunt. Most razors use stainless steel, so if they're rusting on you (rust will be visible), then you're doing something wrong (e.g. using the same disposable blade for too long, not properly drying, etc.)

You should never, ever shave with a rusty blade.

constantino675 t1_j2dusma wrote on December 31, 2022 at 3:05 PM

You're half right. The biggest contributor to dulling is mineral deposits from drying cycles.

If you dry the blade after every use (including a blast of compressed air) the blades can last 150+ shaves with minimal wear.

Antman013 t1_j2dx9kv wrote on December 31, 2022 at 3:24 PM

This is EXTREMELY difficult to accomplish, however, and usually only done by folks wanting "bragging rights". So called "century shavers" . . . in a practical sense, there is simply no need to be this fanatical about edge wear on disposable blades.

I have seen what both a safety blade and a straight razor edge look like under an electron scope, and u/Berek2501 is correct. The "edge" is actually a line of "peaks and valleys" which, after contact with your hair, have the tips rounded off or over. Honing is done to "straighten" or realign those peaks and valleys and restore that keen edge. It's quite fascinating to see how "uneven" a truly "straight edge" is under extreme magnification.