Why m4?

What if the m4 blade comes with a dark gray coating on it already? (Benchmade)
How long should that coating last?
 
I cut various fruit with Maxamet and was surprised to find that Apple left stronger (darker) patina than lemon.
 
Blades under 60HRC rust easier than those above 60HRC. I don't believe in Spyderco's heat treatments. In fact I dislike all major companies HT. I edge quenched my CRKT M16Ti and it's awesome. Before it was - meh.
 
Bob Denman said:
What if the m4 blade comes with a dark gray coating on it already? (Benchmade)
How long should that coating last?
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Benchmade uses Cerakote. I've only had problems getting rust where they etch the logo/blade steel. Other than that, no worries at all! How long it lasts depends. My Super Freek coating has lasted for over a year, and Ive used it quite a lot. I understand the older coatings were not as durable.
 
I wish M4 was more available to get at a reasonable price. I only have one M4 knife, a factory special Kershaw Blur, so it’ll probly end up a safe queen unless I buy another. It seems like a slightly different (more tough) version of m390/204/20CV, and the summer here isn’t too humid.
 
I've got my first M4 coming; so this has been a pretty informative thread.
(Custom Shop Mini-Grip...)
 
SpyderPhreak said:
I'll need to do another. I'm not comfortable posting it for general public consumption for a number of reasons. (ETA: It's just plain yellow mustard lightly dabbed onto the blade with the tip of my finger.)

In my experience, CPM M4 doesn't take a forced patina as heavily as some other steels do, but it still protects the steel just fine. Generally, it just shows light rainbow-like coloring similar to @unclekurty's pic above (hard to photograph, have to get the lighting *just* right). Usually only a small amount of gray staining.

CPM-M4:

View attachment 1611825

View attachment 1611826

M4 with a couple others (Maxamet and Rex45):

View attachment 1611829

Close up of the other two:

View attachment 1611831

View attachment 1611830

Another one, 52100. It seems to patina more than most.

View attachment 1611840

K390 as well (it patinas pretty heavily too, but not quite as much as 52100):

View attachment 1611827
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try this ...........................https://bladeforums.com/threads/phosphoric-acid.1654333/

I like natural patina formed with time.......
AukvBLH.jpg
 
I agree: it looks like a knife with a lifetime's worth of experience.
 
As fantastic as it is, M4 will never hold up to a humid climate and sweat unless you use a coating like Cerakote, PVD or DLC on the blade. It’s just the nature of M4. I always keep my tool steels dripping in oil and they’ll still form a spot or two of rust after a humid day in the pocket.

I haven’t tried it myself, but there is a type of WD-40 called “Specialist Corrosion Inhibitor”. It’s supposed to absolutely prevent rust and it’s $10. I’d try it out unless you use your knife for food.
 
Andrew George said:
there is a type of WD-40 called “Specialist Corrosion Inhibitor”. It’s supposed to absolutely prevent rust and it’s $10
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I'll believe it when people do reasonable comparison tests.
I've watched a lot of tests and although the results can vary from test to test, a lot of the recommended protectants really don't work all that well. In my own experiment Birchwood Casey Sheath worked the best, Royal Purple Maxfilm was next. These both leave a somewhat greasy film on the surface which may be why the work well. You may not want this on a knife that you use. The stuff sold by AG Russell didn't work very well, neither did Renaissance Wax.
 
bdmicarta said:
I'll believe it when people do reasonable comparison tests.
I've watched a lot of tests and although the results can vary from test to test, a lot of the recommended protectants really don't work all that well. In my own experiment Birchwood Casey Sheath worked the best, Royal Purple Maxfilm was next. These both leave a somewhat greasy film on the surface which may be why the work well. You may not want this on a knife that you use. The stuff sold by AG Russell didn't work very well, neither did Renaissance Wax.
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That’s fair. I haven’t tried it and have only seen anecdotal evidence of it working on YT, which means jack. I would like to try it, and many others, on 1095 and see how well it works in a saltwater solution.
 
Natlek said:
try this ...........................https://bladeforums.com/threads/phosphoric-acid.1654333/

I like natural patina formed with time.......
AukvBLH.jpg
Click to expand...
Why would I want to try that? Mustard works quite well for me, and I am very happy with the results. If it ain't broke... 🤷‍♂️
 
powernoodle said:
I've carried knives daily for 40 years, and never required "extreme edge retention" and "toughness" in a blade. Hecky, even "the greatest generation" won WWII with cheapy carbon steel traditionals. Are you guys using your EDC blades in lieu of wrenches to rebuild cruise ship engines? I guess I could see an oil platform worker or roofer wanting that kind of blade (though a utility blade is supreme on the roof), but most of us are using them to open Amazon packages. Seriously, unless you are prying up manhole covers, under what circumstances does a blade steel have to be "tough", and why not use a hammer or pry bar instead?

Kids, these days!
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There was a difference in those steels you mention and now.
The old camillus, and old timer knives I had from 1960’s. Took a keen edge, and kept it for lots longer than exact same knives made in the 1990’s.
 
Monofletch said:
In fact I am waiting for my custom CPM Magnacut fixed blade.
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Whether you think M4 is worth the trouble? ==> Totally personal preference.

Magnacut will be available in production folders before too long. It's toughness and edge retention are right there with Cruwear and CPM 4V and M4, BUT it's nearly a super-stainless. Very balanced. It's going to displace a lot of S30V, S35VN, M4, and Cruwear over the next few years. I'm guessing a Paramilitary 2 in Magnacut can't be too far away, as an example. That would be a decent choice for someone who is sweaty from 8am to 4pm... but see below...

See also Vanax ($$) blades (e.g. Quiet Carry knives). Vanax maxes out at HRc=61, but is super-stainless, and expensive. They make several nice models that are nearly corrosion proof, stem to stern.

For a lot less money than Quiet Carry, Spyderco makes a few nearly completely stainless knives, in the "Salt Series", aka "Marine Series": https://www.spyderco.com/catalog/category/salt-series
I only really like the Spydie Chef of that bunch, but you might find others in that series that suit your eye.
 
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