REX 45 and other "rustprone" toolsteels: Corrosion and by that dulling on the very apex - is it an issue in regular EDC?

[Wartstein]

I remember Sal saying some years ago that the sharpened edges of tool steels—especially but not exclusively—are molecularly reactive with their environment, such that perceptible dulling, if not visible corrosion, is possible. I guess corrosion has to start somewhere. Anyway, before I pocket a different EDC, I strop it several times or drag it back and forth across some white stuff ever so lightly.

Thanks, you did put a lot better what I originally meant! Not real, visible corrosion, but a chemical process similar to corrosion that dulls an edge just by carrying it in a more or less humid enviroment.
So that perhaps a tool steel folder, that would have great edge holding under perfect conditions, still dulls quicker then expected just by being carried in the pocket a lot more than being actually used (what, let´s face it, is the case almost always, even with people who do use their knives rather frequently..)

[Pancake]

Thinking about getting a Manix in REX 45, one big reason (but not the only one!) is the obviously very good edge holding of the steel.

Hey Warstein.

Technically, yes, corrosive envirmonet might degrade edge of tool/carbon steel faster then pure dry air. But, REX 45 has some alloying elements, so I doubt that it will rust just by looking at it.
Like, if you cut a lemon in half and then leave your edge as is, it will degrade a bit, but there are not going to be massive chunks of metal missing from the edge.
Edge apex is very small and chemical reaction are going to affect it, but not in the way that will be dull as butter knife.

Off topic: I thought that you are going to get a Siren :D

[Mattysc42]

It happens, but usually the drop in sharpness people notice is from sharp enough to effortlessly whittle free hanging hairs to sharp enough to split hairs with effort. Outside of extreme edge junkies and extremely corrosive environments, most people will probably never notice a loss in sharpness.

[Wartstein]

It happens, but usually the drop in sharpness people notice is from sharp enough to effortlessly whittle free hanging hairs to sharp enough to split hairs with effort. Outside of extreme edge junkies and extremely corrosive environments, most people will probably never notice a loss in sharpness.

Thanks! And I can see from your signature: You do know your tool steels...

[JuPaul]

It happens, but usually the drop in sharpness people notice is from sharp enough to effortlessly whittle free hanging hairs to sharp enough to split hairs with effort. Outside of extreme edge junkies and extremely corrosive environments, most people will probably never notice a loss in sharpness.

Thanks! And I can see from your signature: You do know your tool steels...

Just buy that rex45 manix already, W!!! :p

[Chumango]

The concern about edge degradation due to corrosion is what kept me away from tool steels for many years. However in the last few years I have used M4 and Rex 45. I have taken both steels on backpacking trips. The only issue I have had is spotting on the blade where sweat condensed on it in my pocket. I noticed more of it with M4 than I did with Rex 45.

I might have seen some edge degradation due to corrosion before but that has happened a lot less than I thought it would have, despite the fact that I don't normally oil my blades, and I live in a warm, humid area - Tennessee. There are things that if I cut and I don't clean it off it might happen. For example, I think that Kudzu is corrosive and I need to clean it off after I cut the vines.

Naturally, cutting acidic foods will result in edge degradation, but I have not seen it from just storing a knife.

[Chumango]

Double post