Does air dull knives?

L

Lavan

Joined
Nov 8, 2000
Messages
2,301
I swear, I can work up a sweat putting a good edge on ANY knife and without USING it, it will be dulling in about a week and a half.
Maybe it is the touching it to see how sharp it is every day.
 
If I'm mistaken, I'm sure I'll be corrected, I remember reading somewhere that any unprotected edge will eventually degrade over time, due to the oxidization of the metal, that's why polished edges seem to stay sharp over time, they have a coating that retards oxidization. I honestly believe the effect is negligible, on anything short of an antique paper thin razor, you probably wouldn't take notice.
 
Maybe when you run your finger down the edge, you're leaving behind some oils and sweat that makes the edge corrode more quickly. When I'm not lazy I wipe the edge with Tuf-Cloth right after I sharpen. Of course, the layer of Tuf-Glide would probably come off soon as I use the knife, but I think it might help keep the corrosion away until I really use it.
 
Yes, it does, though oxidation. But the affect is very slow. We're talking decades here, not days or weeks.
 
To ad to what T said,

do not forget that steel is an elastic material, and steel at the edge can move, semlingly by itself. Take a knife that has been used and you steel the edge straight. If you do not use the knife, the edge will slowly "de-steel" itself and return to its dull shape. THis phenomenon can work in the opposite direction too- sharpen a knife, use it and then leave it for a few days, and any "damage" from use will "work itself out". I have heard that if you take 5 razor blades and use each blade once and keep rotating them, the razor blades will last longer than if you used each blade one by one until the blade was too dull to use.

As far as your edges go, you bay be experiencing this bending effect, or your edges may be rusting. Are your blades carbon, or stainless steel?
 
ATS 34 and will dull out with slightest use. Elishewitz Benchmade 910 (?)

Hard to sharpen and even harder to stay that way.

I even used to sharpen my Buck 110 easier than this one.
 
Originally posted by Lavan
I swear, I can work up a sweat putting a good edge on ANY knife and without USING it, it will be dulling in about a week and a half.
Maybe it is the touching it to see how sharp it is every day.
Click to expand...

I swear the same thing about any of CRKT's AUS6 stuff.

Doug
 
Steel does not move much at all and does so incredibly slowly, so I doubt that is your problem. This is something that I have never heard of before. Veeeeeeeeery interesting.
 
One thing I've noticed since moving to the harder alloys, ATS 35, VG 10, and the rest, isthat they are much more difficult to sharpen with conventional stones,(not impossible, just more difficult), it takes longer freehand, and unless your real good at holding that final bevel, you'll tend to roll the edge.

You didn't say what you were using to sharpen with.
 
Sometimes diamond, sometimes Lansky stone (flat part) and always ceramic V-stick finish up.
 
Does air dull knives?

At first I thought this was a straight forward easy question & was going to quip: It depends on how much pollution is in the air your're trying to cut! If I'm correct, I believe a person's skin oils can be on the acidic side but I wouldn't think it would affect the sharpened blade so fast. Oxidation would be speeded up in a humid climate. Is the knife kept in a sheath - perhaps the oil or stain is affecting the edge or the blade is rubbing on something each time it's inserted or removed - just a guess.
 
I believe a person's skin oils can be on the acidic side
Click to expand...

Now there's an interesting thing to consider. The other question would be: are you putting anything else on the blade after sharpening it and are you removing any oil or other material used in the sharpening process.
 
Corrosion can take the edge off of steel very quickly depending on the enviroment. Some peoples sweat is far more acidic than others. It is trivial to test if that is the reason. Sharpen two knives, touch one as you normally would and leave the other alone. Compare after a couple of weeks. Switch the knives and repeat to insure you are not seeing a geometry or steel influence.

-Cliff
 
Are they stored North-south, or east-west? Makes a difference you know;)
 
Cliff is dead on! Carbon steel edges can dull just by sitting around due to corrosion. He is also correct in that people's body chemistry can do very strange things to ANY steel. We have all heard the arguments that this steel or that steel IS NOT very corrosion resistant because it spotted very quickly but of course, it's for THAT INDIVIDUAL! If you do have "toxic sweat" and are stroking the edge EVERY DAY, yes, THAT could dull it but I doubt it in a week and a half.
 
I think the same thing happens to me. This is a pretty low tech answer, but, if I REALLY work at getting a knife really sharp...when I go back to it, it doesn't seem as sharp. I don't know if my fingers get numb, or, I just decide its as sharp as its going to get and stop, only to play with it later and realize it wasn't as sharp as I thought it was...Seems pretty simplistic, but, I'm sure its happened to me.
 
Originally posted by Sgt 127
I think the same thing happens to me. This is a pretty low tech answer, but, if I REALLY work at getting a knife really sharp...when I go back to it, it doesn't seem as sharp. I don't know if my fingers get numb, or, I just decide its as sharp as its going to get and stop, only to play with it later and realize it wasn't as sharp as I thought it was...Seems pretty simplistic, but, I'm sure its happened to me.
Click to expand...

I do believe you are correct sir! :D I experience he same thing, my test is does it slice paper and shave hair, thumb is used to see if edge has rolled :D


Corrected for fatal spelling errors.
 
Is is possible that it's just a wire edge, and the testing of the edge gradually rips it off over the course of a week, and gradually you're left with a dull knife again?

just a thought... ...interesting thread though :)
 
Sgt 127 :

if I REALLY work at getting a knife really sharp...when I go back to it, it doesn't seem as sharp.
Click to expand...

If you steel or strop the edge as a finish this is the expected behavior as the edge will relax back to its predeformed state quite quickly. You can see similar effects to lesser extents on v-rod sharpening depending on how much pressure you use. I have seen in on all manner of steels and even on ceramic blades.

-Cliff
 
Originally posted by Cliff Stamp
If you steel or strop the edge as a finish this is the expected behavior as the edge will relax back to its predeformed state quite quickly. You can see similar effects to lesser extents on v-rod sharpening depending on how much pressure you use.
Click to expand...
Wow, I never thought of it this way. So too much pressure causes the metal to deform the way you want, but doesn't really remove metal as efficiently?

I always push really hard on my Sharpmaker rods, it makes me feel like I'm getting more done. It's also my only form of exercise. :D Maybe I ought to try going a little lighter on the stones.
 
You must log in or register to reply here.
Back
Top