M4 blade coating?

[faeriequeene]

I just picked up a Spyderco Sage 5 in satin M4 (mostly because I loved the scale color). I’ve read that M4 is prone to corrosion, and I live in the southern US where it’s humid AF for half the year. Would adding a DLC or similar coating help to prevent rust on the blade?

 

[tinfoil hat timmy]

rustoleum grill paint

 

[c7m2p3]

Keeping it oiled should also do the trick. I actually dont mind the discoloration after carry and use though it gives it some character.

 

[chalby]

I just picked up a Spyderco Sage 5 in satin M4 (mostly because I loved the scale color). I’ve read that M4 is prone to corrosion, and I live in the southern US where it’s humid AF for half the year. Would adding a DLC or similar coating help to prevent rust on the blade?

If it's going to get regular usage, then you could just give it a light coating of mineral oil or whatever. The problem with relying on coatings like DLC and living in a humid climate(like I do) is that the edge can dull from the corrosion.

I have a rotation of folders that I carry and ones in M4, Maxamet, K390 can be noticeably duller after sitting around for a few weeks in the wet season. After I noticed it happening I started regularly oiling them and the problem more or less stopped.

If I was storing them for long periods I would probably use Ren Wax or something similar for a more durable protective coating.

 

[sodak]

You could give it a forced patina, some people don't like the look, but I do. I've used lemon juice and a raw potato, but others report good results with hot vinegar.

 

[Alberta Ed]

M4 will take a patina but after a year with y GB2 I notice only a few tiny spots that don't affect its utility at all. It's pretty corrosion resistant steel.

 

[chalby]

M4 will take a patina but after a year with y GB2 I notice only a few tiny spots that don't affect its utility at all. It's pretty corrosion resistant steel.

I like M4 a lot, but I'm willing to bet you don't live in a tropical/humid climate.

It's among the least corrosion resistant steels out there not including carbon steels that have no chromium.

 

[Crag the Brewer]

I like M4 a lot, but I'm willing to bet you don't live in a tropical/humid climate.

It's among the least corrosion resistant steels out there not including carbon steels that have no chromium.

Sure, but tribes in tropical jungles have used leaf springs for over a century without troubles.... Patina and a little rust never hurt anyone.
I'd love a good M4 blade.

Currently I'm loving on some bare M2..... in a slightly drier environment, but we still get humid days.

 

[chalby]

Sure, but tribes in tropical jungles have used leaf springs for over a century without troubles.... Patina and a little rust never hurt anyone.
I'd love a good M4 blade.

Currently I'm loving on some bare M2..... in a slightly drier environment, but we still get humid days.

Totally agree. I was just addressing the comment "It's pretty corrosion resistant steel". It's not.

 

[Alberta Ed]

I like M4 a lot, but I'm willing to bet you don't live in a tropical/humid climate.

It's among the least corrosion resistant steels out there not including carbon steels that have no chromium.

True, Alberta's pretty dry. M4 does have a bit of chromium in it though, along with the other alloys. I usually wipe the blade with a bit of BreakFree CLP after sharpening, which helps.

 

[Twindog]

I live in a rain forest, not far from the ocean. M4 is a great steel, but in my environment I have to take care of it -- keeping it dry and oiled.

The problem with M4 corrosion is that it doesn't just rust, it pits. But pits are avoidable if you take care of it.

On the other hand, why not just get a stainless steel? There are awesome stainless steels in today's knives.