GB2 and M4

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Jan 14, 2007
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Just looking for opinions of the Spyderco GB2 in M4? I've narrowed my next purchase down to two and it is all down to the blade steels. Either Cruwear or M4 and both are not stainless which is what I usually go with for EDC.

How does the M4 hold up under normal exposure and EDC use. Not in a salt water environment but I've heard that M4 can rust in humid weather regardless.
 
M4 holds up great, actually. I'd say it's more stain resistant than K390 and such. I have and trust it on a few knives, fiance carries M4 every day at work. CA.
I do not have the GB2 but I have the GB Advocate and have no fear of random rust, especially with care.
 
I guess it depends on what you consider normal exposure and EDC use.
Here’s mine after a few years. Ive never put any oil on it. Wipe off the blade after use as I do on all my blades. (My work folders would tend to differ with me on that😁)
Tried to get the blade in the right light to show the spotting. If you blow it up you can see it. Especially around the logo.
I live in Texas where it can get fairly humid at times.
No experience with Cruwear so I can’t compare the two steels.
C180ACD5-C7B6-4AC3-AF0E-6E0986F95F57.jpeg
 
I had similar concerns about M4 before recently getting a GB2, as I live in central Florida and it’s almost always very humid here. Like the OP, I generally opt for stainless steels. I’ve been carrying it very frequently since I’ve had it (probably two months now, which I concede is not an exorbitant amount of time), but I have seen absolutely no issues so far. I absolutely love the knife, and am not worried one bit about it crumbling into dust. I’ve also noticed no issues on the bare edge of my Mini Adamas in Cruwear, but the rest of the blade is coated.

I don’t spend much time around saltwater these days, so I have no input regarding marine exposure, but I do sweat plenty, and that has been inconsequential so far.

I did service a buddy’s M4 Bailout recently, which had apparent rust starting on the uncoated edge and on the exposed lasered logo on the blade, but he is notoriously neglectful of his knives, which is exactly why he sends them to me to sharpen and tune up. Some oil and elbow grease cleaned it up fine. Knowing him, he probably dressed a deer in a swamp somewhere and threw it back in his bag coated in who knows what.

I am very impressed with the edge M4 takes, and will not rule it out if something else that catches my fancy in it comes up just because it’s not stainless.
 
I've been very impressed with Cruwear's stain resistance given that it's not stainless. It's very forgiving. Really I've been very impressed with Cruwear all around. It opened my eyes to the awesomeness of tool steels. That lead me to set aside my fears of corrosion and try M4 too and so far I've not had any rust with just moderate maintenance.
 
I'm in a tropical climate and generally don't have an issue, although I use mineral oil on my non-stainless blades, however I did have an issue with M4 recently.

I'm in the southern hemisphere, so in the middle of the summer/wet season now. What happened was I went for a short hike in the morning(so a bit sweaty etc.), came home and put the M4 Para 3 in my pocket and was just doing normal stuff at home and when I pulled out the knife at the end of the day the entire surface that was against my leg inside my pocket was covered in surface rust. Most of it came off easily but there is still a small amount of almost pitting still there although you would need to look carefully to see it.

I was shocked when I saw that, and now am more reluctant to use my tool steels/carbon steels during the wet season.

TL;DR in my environment I lean more towards stainless if I can help it these days, but it wouldn't stop me buying a knife that I liked.
 
Just looking for opinions of the Spyderco GB2 in M4? I've narrowed my next purchase down to two and it is all down to the blade steels. Either Cruwear or M4 and both are not stainless which is what I usually go with for EDC.

How does the M4 hold up under normal exposure and EDC use. Not in a salt water environment but I've heard that M4 can rust in humid weather regardless.
It is one of my favorite steels but M4 can rust and sometimes pretty easily. I cold blued mine and it hasn’t rusted since but it will still need more maintenance and care than a stainless steel.4CD8DEBA-7DFC-4C90-89EB-6964AF6283B6.jpeg
 
my gb2 is great, no rust issues but I'm in Canada, not near the oceans...

it takes and keeps an edge for a very long time... the hollow grind & m4 means that a simple stropping is all thats been needed to keep an excellent edge (in my use case, which is mostly heavy cardboard boxes, the odd strap, and the usual stuff around the house)

I did plan on doing natural bluing (spray to rust evenly then submerge in almost boiling water) but so far it's been much more rust resistant than expected...

I may likely still do that but so far it's remained amazingly in like new condition after 4+ years

D DMG did you do your bluing that way or use the liquid bluing stuff?
 
No rust on my M4 knives but lots of patina.

pCxVFc4.jpg
 
my gb2 is great, no rust issues but I'm in Canada, not near the oceans...

it takes and keeps an edge for a very long time... the hollow grind & m4 means that a simple stropping is all thats been needed to keep an excellent edge (in my use case, which is mostly heavy cardboard boxes, the odd strap, and the usual stuff around the house)

I did plan on doing natural bluing (spray to rust evenly then submerge in almost boiling water) but so far it's been much more rust resistant than expected...

I may likely still do that but so far it's remained amazingly in like new condition after 4+ years

D DMG did you do your bluing that way or use the liquid bluing stuff?
I used Birchwood Casey Super Blue. I have used it on tools in my shop to slow rust, too.
 
I have a Spyderco Mantra 2 that's in M4. The stuff doesn't rust like crazy, however I've definitely noticed a large difference from my stainless knives. I cut something at work wet, probably some pallet wrap and wiped it on my jeans however apparently it was still a little wet. I put it away just like that that night and when I grabbed it the next time, maybe a weak later, there were a couple little segments of pitting. I polished it numerous times with metal polish on a rag, on leather etc., yet the pitting is enough to where it's still there. It sharpens easier than I though it would though and I still really like the steel.
 
Not issues with my cru or M4 in Alaska. But I will rub down with a dab of food grade mineral oil from time to time. Can't say it needs it but I do it from time to time. Took my crucarta sledding for several hours today. It's still in my wet coat. Don't really care, I'll get to it later...20230101_183941.jpg
 
I tried, somewhat successfully, to make my GB 2 blade patina in vinegar. It wasn't easy. Other than a few spots on the lettering and bug, no rust. I wouldn't worry about it honestly. Love my GB 2.
 
Just smear a wee bit of Breakfree CLP or Rem Oil (both gun protection products readily available at most sporting goods stores or departtmets) on the GB blade. I have used it on my firearms and GB1 for many years without any problems from corrosion.
 
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