Home Forums Gear Knives and Blades M4 blades

I have noticed my M4 blade is getting a little patina on it. Anyone else? Normally this kind of oxidation has a somewhat protective ability and this is not unattractive. Anyone know anything about this with M4? I have a CPM 154 blade that sort of has the same thing, but to a much smaller degree. I do nothing to protect the blade. I cut deer with it and wash it in the sink and then it lives in a leather sheath.

I believe that somewhere in the last year of CPM M4 threads, I stated that CPM M4 will develop a patina and/or rust depending on care.

So called "stainless" blade steel should really be called stain resistant, with levels depending on specific chemistry.

Good to wipe off a blade when used and put in sheath as reasonably clean as can.

Clean with hot water and dry quickly when can.

I use Gibbs Metal Protector on my blades. Leaves a slight film, but dries and works well for me.

Long term storage in a leather sheath is not a good practice. Tannins and crud are not good.

I did a forced patina using ferric chloride on one of my M4 blades and it looks pretty cool. Might also help protect.

If anyone has issues or concerns with my knives, please contact me.
Tim

I have a customer who never cleans outdoor knives. Just uses and sets aside. Only clean looking area is the cutting bevel
when a re sharpening is done. The CDC would declare his knives a bio hazard. But he loves them and uses the heck out of them.

Picture(s)???

I like the look of mine the way it is progressing. Like I said, most patinas on knife blades does tend to be protective and some are like case hardening.

I can take a pic on my smart ass phone if someone can post it here.
I am not currently able to post pics here, but can message them.

^ Happy to, Tim.
You've got my number.

Here ya go:

Thanks Tim/longarm!

That's sort of where mine looks like it's heading.

It's a good look!

To answer your original post, my M4 blade is developing some patina as well. From what I've read M4 is a low chromium steel and so its not a true stainless. The patina doesn't bother me in the least.

chapstick works well

Heat treat and finish are the best inhibitors of surface corrosion on M4. But even that said...it WILL...