Knives lose sharpness just sitting

Sep 20, 2015
I guess that means you don't save unused razors or razor blades for years without using them....

Oh yeah . . . disposable razor blade cartridges need to come with "expiration dates".
Sure . . .
Oh and keeping them in the refrigerator will keep them fresh longer.

The Mastiff

Gold Member
Apr 21, 2006
True or not I can't say but this idea of edges dulling goes back longer than any of us here. I heard it as a kid. I also heard that steel gets "harder" when it gets older too and I know of no evidence supporting that either. I have noticed edges dulling on knives that were unused but only from very high sharpness levels to slightly less sharp. I thought it was corrosion on the edge and didn't worry about it because my edges were still darn sharp. They were just not as breathtakingly sharp as they were when I put them up.

Does anybody here else remember the folding portable pyramids sold in ads in the back of magazines for the buyer to use for that good "pyramid power" to help keep razors sharper and fruit to last longer ? It was back near the sea monkey and X ray glasses ads. :)

Nov 19, 2014

In the electron microscope world, some people say (or at lease used to say) that a glass knife loses its sharpness quickly due to deformation because glass is "super-cooled liquid".
But some others say that they can store knives for weeks without seeing any performance degradation.

I guess it is more complicated for steels and would like to hear what @ToddS would say.


Platinum Member
Jun 29, 1999

…. some people say (or at lease used to say) that a glass knife loses its sharpness quickly due to deformation because glass is "super-cooled liquid"....

It used to be common knowledge, that glass tended to flow over time, and that it was clearly evidenced by looking at the ancient window planes that survive on medieval churches and buildings. It turns out that wasn't the case. The apparent glass flow were actually original manufacturing defects, they lacked the technology to produce perfected flat glass plane.

Mar 13, 2013
I had to look that up. Fascinating. From one article, "In fact, in old churches, for example, some windows are fatter at the bottom, while others are fatter at the top, depending in the way the builders happened to put them in," said Royall, who had this pointed out to him by his colleague Stephen Williams at the Australian National University in Canberra.