Corrosion resistance: S30V vs. VG10 vs. CPM M4

mattz357

mattz357

Joined
Jun 20, 2002
Messages
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I'm looking at a couple of Spyderco knives and am a little torn between two with these blade steel options. I have a bad tendancy to rust things with my corrosive sweat, so I'm wondering which steel has better corrosion resistance. I take good care of my stuff, and don't mind wiping the blade down every couple days, I just don't want to get into a situation where I will inevitably have rust on my knife. Any info is greatly appreciated!
 
I haven't had any experience with M4, and while S30V is by far my blade steel of choice, I've found VG10 to be more rust resistant.
 
i believe m4 is carbon so it can rust easy. s30v and vg10 are stainless so they're all good. which one is better...no idea....
 
s30v and vg10 are both pretty hard to rust. I've had virtually no problems with corrosion on either of the steels. Have heard of some people having problems in very dirty saltwater jobs, but I can't speak on that.

CPM M4 is much less stain resistant. It is not as bad as something like 1095, but will still stain and discolor if you cut up some fruit or something and let it sit without washing, the usual stuff. But I've had it on me clipped inside my waistband for all sorts of hot sweaty days, had it out and about in snow, hikes, work days, bike rides, etc... and had no problems.
 
S30V and VG10 are good, M4 with patina, then rust. If you wipe it down, it won't rust very easily, it will just patina. But M4 holds an edge FAR better than the other two, and is tougher as well. Out of those steels, I'd definitely choose M4. It's price range is typically much higher than that of S30V and VG10 knives.

If you're really concerned about rust, though, H1 is your best option. It will not rust, even if you store it in a jar of vinegar for a month (you can look around to see some of the tests people have used).
 
As I understand it (I have a Gayle Bradley being shipped to me as we speak, but I've never had first hand experience with it), M4 will get patina super easy, but I don't think that means that the blade is getting rusted through. S30V is just the do-it-all steel, excels at everything. Don't have much experience with VG-10.
 
Of those 3, VG-10 is my choice for a kitchen knife due to superior corrosion resistance, and M4 is the choice for hard use, due to great toughness and edgeholding. S30V is a good all-rounder.
 
I've been using my GB and M4 Military a lot and haven't seen them get red rust, though they are both quite stained. I don't imagine it's the best of the three set in bad conditions.

VG10 has rusted on me on a few hot summer days with the knife sitting in my pocket, so I wouldn't suggest it. It wasn't bad, just peppering of red rust over part of the blade.

S30v I've only had one case of rust, under the thumb stud on a Benchmade 940.

S30v wins in my experience.


edit: Here's a (poor) picture of GB in its current state. Everything behind the hole I hit with a dry-on lube, so that has stayed nice and shiny. No red rust has showed up, but it's got plenty of white and bluish staining. Pardon the mess in the background :p

SnPTm.jpg


ECVwn.jpg
 
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I've had a lot of both. I believe on one of my old VG10 knives there are some very, very small rust spots forming that I polished out in like 30 seconds. No prob.
As far as I can recall, none of my 10+ S30V knives ever had rust, except I've seen surface rust on COATINGS, but that doesn't count. I'm not sure if that coating itself rusts, or it somehow causes rust spots...
 
my dobson custom parer sees daily use--no rust but does develop a patina. if discoloration is your priority then go with vg10 or s30. s30 is certainly a decent stainless but the edge durability of m4 is world class. of course m4 costs more but my m4 parer will be cutting when vg10 & s30 are on the sharpening bench.--dennis
 
Check the pics below out. If you process a deer and don't clean the blade, you will get the results shown. The knife is a CPM-M4 Spyderco Mule.

rustm4front.jpg


rustm4back.jpg
 
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