Kershaw blade steel and corrosion resistence

Vivi

BANNED
Joined
Dec 4, 2005
Messages
5,095
The Leek I traded for a couple of weeks ago has become one of my favorite knives very quickly. I love the bladeshape, thin blade, the semi guard, AO opening (I don't like thumbstuds so AO fits the knife nicely for me), it's thin and light yet just long enough for a 4 finger grip etc. I'm sure you all know. It's a classic knife and I'm just late to the game.

Today though I think I encountered the first thing that's given me any real trouble with the knife. All my previous worries were resolved, such as the AO needing breaking in and reprofiling being tricky because I couldn't get the thumbstuds out. The Leek was in my pocket all day and it was pretty warm out, so I was sweating most the day. Now my Leek is spotted with rust on the blade. Doesn't appear to be on the liners or anywhere else though thankfully.

Knife steel rusting when being exposed to sweat all day is nothing shocking. The only thing that kind of irks me is most my other knives don't exhibit this kind of behaviour. The Leek was spotted all over, and after scrubbing for a minute with a kitchen brush the spots are still lightly visible. I'll live, I'll leave it as is or sand them off, no big deal. It just seems like my Kershaws rust more easily than other knives.

I have a G10 Cara Cara from Byrd and an Endura 3 in ATS55 that have both seen a lot of pocket time while I sweat, neither has rusted at all. My Buck Hartsook (reprofiled flat to the stone, thereby removing much of the blade coating) is the knife I often carry when I plan to be active since it's thin and light, and after a full day of being soaked in sweat it's usually rust free. The only time it rusted at all there was one small spot of rust and it wiped right off with my shirt.

My Kershaw Groove also has some tiny rust marks on the blade near the spine that wouldn't rub off easily. My friends Vapor also seems a little more prone to spotting on the blade than other knives I've used.

Does your experience match mine, in that Kershaw's seem a little more prone to rusting? This seemed a little odd to me for a 440 series blade steel knife, but maybe someone with more knowledge about the elemental composition of the knives I mentioned could chime in.

EDIT: Something I forgot to mention is there was no rust where the edge bevel is (Ground out with a fine diamond stone from DMT), only where the Satin finish is. Does this finish make the knife more prone to rusting? That's how it appears from what happened today.

EDIT: Kind of unrelated, but could someone direct me to a page that has photos and info on all the available Leek variations? I really like the knife and I'm considering the G10/440 model. I'd like some photos comparing the thickness of this model to others as well as a page that just has all the variations so I can compare them and pick out my next Leek. My thanks to Kershaw for producing this fantastic knife as well, you've won a new customer between this and the Groove.
 
Your leek is probably bead blasted. It is a common blade finish that looks nice and is cheap and easy to do, however, it is more prone to rusting.
With a bead blast finish the surface of the steel has been given lots and lots of little divots on the surface, if you were to look at is under a microscope it would look kind of hilly, or bumpy. All the hills and bumps have lots of surface area, and so they have that much more steel exposed to be able to rust. The ideal finish for resisting rust (other than some type of coating) is highly polished. Under a microscope the polished finish would look flat, rather than bumpy. The flat surface exposes much less metal and so corrosion is much slower to start.
A highly polished finish is also time consuming and hard to do.

Hope that helps.
 
Thanks for the information. I might try polishing the blade with some 1000grit sandpaper at some point.
 
Vivi, here's a copy of a post I made a day or so ago. Sounds silly, but these beauty supply places have some wonderful big nail files, up to 5000 grit...and they're very soft. I've bee using them for a few days now to polish up some old blades...

05-30-2007, 04:52 AM
SPXTrader
Registered User Join Date: Dec 2006
Location: Southwestern VA
Posts: 103

Just FYI, I had the pleasure (HA!) of going to a place tonight with my wife called "Sally's Beauty Supply" It's like a specialized Wal-Mart for hair dressers, beauticians, etc.

Well, while she did her thing, I was wandering around, I came upon a nail file section. Amazing! 8"X1", and grits up to 5000. Whats more, they're thick and have padding between the two sides. About a buck or two per each. I bought a combo with 500 and 750 on one side, and 1000 on the other. Came home and grabbed an old Chinese stainless that was stained, and started in on it. 15 minutes later it was shiny as new!

I'm thinking about buying a few of the 5000 grit ones to do some real edge polishing.

Any thoughts on this maneuver?
 
SPX, that sounds like a great idea. I think I'll stop by somewhere today and see what they have in the cosmetics section.

I was using small sections of 2000 grit sandpaper (Forgot I had that high of grit) today on the Leek and here's what it currently looks like:

6cr9zf7.jpg


It's turning out good so far. I was kind of wondering if you can take out just the blade on the Leek and put it back in without taking apart the entire knife. I thought the speedsafe bar might need to be re-inserted or something, making what I want to do kind of difficult. I'd like to polish up the guard and pivot area but I don't feel like taking apart the entire knife and buying some new torx drivers.
 
Back
Top