Vivi's M4 Manix XL DLC Corrosion Log

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Albatross
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Re: Vivi's M4 Manix XL DLC Corrosion Log

#21

Post by Albatross »

TkoK83Spy wrote:
Tue Oct 06, 2020 1:31 pm
Wartstein wrote:
Tue Oct 06, 2020 1:08 pm
This puzzles me again and again. The "composition of sweat" or perhaps the combination of ones sweat and the climate they live in must have such a crazy wide range..

I am sure my knives see a pretty similar exposure to sweat and the elements as Vivis does. Carry them on hot summer days in pocket or IWB, sweat a lot, they live in soaking wet pockets and packs, I cut all kinds of stuff including food, I don´t oil them (except the pivot area occasionally) and don´t always dry them when I could: But I almost can´t rust knives and really don´t know why

Even my HAP 40 blades only show a patina but no rust (on exposed HAP 40 part, the SUS 410 does not rust anyway), only my pretty new Manix 2 LW in REX 45 (not babied at all, and used for cutting fruit and meat several times already) shows tiny specs under a certain angle and light.... :confused:
My understanding is a patina is a barrier against rust/corrosion? Once you form a patina, that area won't rust? I feel like I've read that before. My Vtoku2 Dragonfly and when I had my Hap40 Delica, both have/had a patina at the laminate line but no rust.
A patina wont completely stop rust from forming, it will just take longer for the rust to form. Hypothetically, a patina could outright prevent rust, assuming the knife was previously being pushed just a bit beyond it's corrosion resistance abilities.

Both rust and patinas are forms of corrosion.
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Re: Vivi's M4 Manix XL DLC Corrosion Log

#22

Post by vivi »

Very interesting update to share.

I started the day by making omelettes. Cut ham, onions, bell pepper and a block of cheddar with my Manix.

Image

Later I hiked up a mountain with it clipped IWB on my running shorts. About 2.5 hours up, 1.5 down, sweaty the entire time as it was in the low 80's today.

Image

Here is the blade after the ascent. Notice the spotting from sweat exposure. The strange white line was from stabbing a milk jug of all things. I do this before tossing them in the recycling bin, never have seen it leave a mark:

Image

Looks a little rough. While at the summit I tried rubbing it with my thumb to see how much of the spotting would wipe off:

Image

Ok, looks a lot better now huh?

Now lets look at how the blade looked after I got home, having given the blade another two hours exposure in my sweaty waist band:

Image

Wow! That's ugly! Tons of spotting. This is close to what I would expect from uncoated M4!

So I did the exact same "cleaning" process. I rubbed my thumb over the spotting. No water, no soap, no oil, no barkeepers friend, no magic eraser, no scouring pad. I simply rubbed my thumb across the blade a few times, nothing else:

Image

Yeah. That's what it looks like now. Just from rubbing my thumb across the blade a bit.

These results were fascinating to me for two reasons.

One, I have never witnessed such severe spotting on any DLC Spyderco.

Two, I have never seen such severe spotting on any blade, even stainless, simply wipe off that easily.

I'm not 100% sure what conclusions to draw, but I'm going to proceed as intended.

One conclusion I can absolutely draw from today, is uncoated M4 would not look that clear after being exposed to my sweat for ~5 hours then being wiped off with a bare finger.

Make of it what you will. The tests will keep going :)
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Re: Vivi's M4 Manix XL DLC Corrosion Log

#23

Post by James Y »

Could it be remotely possible that the corrosion on the DLC was perhaps metallic residue from the manufacturing process that was somehow embedded on/in the DLC?

I don’t know. Kinda like when some people report rust forming on the “H1” etching on the H1 Salt blades (which is without a doubt leftover residue from the tooling process). Just throwing that out there.

Jim
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Re: Vivi's M4 Manix XL DLC Corrosion Log

#24

Post by Tucson Tom »

vivi wrote:
Mon Oct 05, 2020 10:55 pm
I rust anything that goes in my pockets. Apparently I sweat battery acid.
Ha ha! Well, I find this thread fascinating. My esteem for DLC goes up all the time.
The stuff is incredible (and/or the place that does the DLC for Spyderco is top notch).

Thanks for doing and documenting this.
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Re: Vivi's M4 Manix XL DLC Corrosion Log

#25

Post by vivi »

James Y wrote:
Tue Oct 06, 2020 8:07 pm
Could it be remotely possible that the corrosion on the DLC was perhaps metallic residue from the manufacturing process that was somehow embedded on/in the DLC?

I don’t know. Kinda like when some people report rust forming on the “H1” etching on the H1 Salt blades (which is without a doubt leftover residue from the tooling process). Just throwing that out there.

Jim
Possibly.

For what its worth there's no corrosion (yet) on the two exposed metallic surfaces of the knife.

Image
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Re: Vivi's M4 Manix XL DLC Corrosion Log

#26

Post by TkoK83Spy »

I've always been a strong advocate for DLC as well, stainless or tool steel. Glad to see you putting this all together Vivi, well done. It's a great feeling to be able to change even one person's perception on something when they may not have believed or considered it otherwise.
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Re: Vivi's M4 Manix XL DLC Corrosion Log

#27

Post by kobold »

I think the spots are simply the dried on salt in your sweat.
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Re: Vivi's M4 Manix XL DLC Corrosion Log

#28

Post by vivi »

kobold wrote:
Tue Oct 06, 2020 9:24 pm
I think the spots are simply the dried on salt in your sweat.
That's certainly possible. I know after a long, hot day I have visible salt crystals on my arms, face etc.
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Re: Vivi's M4 Manix XL DLC Corrosion Log

#29

Post by Bloke »

vivi wrote:
Tue Oct 06, 2020 10:18 pm
I have visible salt crystals on my arms, face etc.
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Re: Vivi's M4 Manix XL DLC Corrosion Log

#30

Post by Bill1170 »

Because DLC coating is both rough in texture and dark in color, it will show smears where light materials rubbed off on it. I wonder how well a wash with soap and water does at removing all oil from DLC. It seems possible that the oil deeper down in the porous coating is very resistant to being washed out.

I laughed at Vivi’s remark about his blades smelling like onions. Growing up with carbon steel knives, I grew to detest the odor of onion combined with steel patina. Stainless blades exhibit a lot less of that unpleasant smell.

This is an interesting test; I will follow this thread with rapt attention.
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Re: Vivi's M4 Manix XL DLC Corrosion Log

#31

Post by vivi »

Bill1170 wrote:
Tue Oct 06, 2020 11:20 pm
I laughed at Vivi’s remark about his blades smelling like onions. Growing up with carbon steel knives, I grew to detest the odor of onion combined with steel patina. Stainless blades exhibit a lot less of that unpleasant smell.
I remember using an Old Hickory carbon chef knife at my first apartment that was theworst withthat. Not only could you smell that knife while using it, but it turned things slightly brown when they were cut.

I appreciate a good carbon steel, but aside from tests like this thread I'm using all stainless in the kitchen these days.

That Police 4 I mentioned....I noticed it started to get a "rusty" smell. That's what led me to inspect the insides and discover all that rust forming on the liners.
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Re: Vivi's M4 Manix XL DLC Corrosion Log

#32

Post by legOFwhat? »

Looks a lot like one of my old baseball caps after a long tournament. Sweat crown of victory!
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Re: Vivi's M4 Manix XL DLC Corrosion Log

#33

Post by Cambertree »

Interesting results, Vivi.

I’d be wary of pinhole pitting sites starting to initiate under that DLC coating. In my experience, M4 can be susceptible to this. I bought my GB1 preowned, and it had a few deep pinhole pits from a fingerprint which had been left on it. Hand sanding them out was a laborious process.

Yeah, I also like the Manix for basic food prep - the 52100 version is great for that. But I always clean and dry and oil it after use.

I should clarify that I have had corrosion on the exposed edge of the 52100 blade, but that’s normal for a simple carbon steel. I just meant I haven’t had any visible rust on the DLC portions.

Rick - patina is a black oxide. It offers some very minimal resistance to red oxide forming, but not much. I have a lot of basic carbon steel knives in my accumulation, and honestly they can be a PITA to maintain, when not being used. When they’re in constant use they’re fine really.

Wartstein - I suspect the ‘body chemistry’ thing would actually mainly be high sodium levels from diet.

Julia - I tried to find that discussion about Pelagic experiencing rust through DLC in a marine environment, and he confirmed that he had not oiled the blade at all.

Here’s a quote from Emanuel from that discussion:
emanuel wrote:
Tue Nov 26, 2019 6:59 am
The reason why it doesn't rust-proof metals is because the deposit method we use cannot create a uniform enough layer so imperfections/pores will occur, so all those imperfections allow oxygen, salt or other catalysts to reach the metal beneath. On the other hand, the porosity helps with absorbing and holding oil which is why DLC is known to reduce the need to oil carbon blades simply because its harder for the oil to be wiped away by use. So yes, the rust you see is the steel beneath it, not something on the DLC. If someone has a good microscope to look at those rusty zones after they're cleaned up, I'm sure it would be clear for everyone what actually happened to the coating during the rusting process.
(Clicking on the arrow, will take you back to that thread and interesting discussion.)
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Re: Vivi's M4 Manix XL DLC Corrosion Log

#34

Post by vivi »

I'm not concerned with the blade rusting. Worst case scenario I can strip the blade and force a patina. If I can enjoy carrying a K390 Police 4, an uncoated M4 Manix with coated liners will be even easier to maintain. The K390 bladehasn't been corroding bad for me, just the liners, so I know the Manix will be ok with a stripped blade.

I'm enjoying this experiment. Put it through another hot and active day today clipped to my waist band. Took a look at it while I was using it to slice some 1/2" poly rope and it looked pretty spotted. I'll be posting another update tonight using the same cleaning method, sharing before and after photos.
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Re: Vivi's M4 Manix XL DLC Corrosion Log

#35

Post by Cambertree »

Cool. How are you liking the M4 in that platform otherwise? And can you make any general comments and comparisons to your S30V XL model yet?

I bet it would be a beast of a cutter with one of your acute 300 grit diamond/7 μm stropped edges

I get a lot of enjoyment out of M4, it’s definitely in my top 5 favourite steels.

Yeah, I generally don’t worry about the blade rusting either. Where I appreciate the benefits of DLC and stainless cladding are in the pivot and tang area.
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Re: Vivi's M4 Manix XL DLC Corrosion Log

#36

Post by TkoK83Spy »

M4 is one of those steels I see starting to disappear, and that's a shame. It's great! I only have 1 in M4 these days (DLC Para 3) and it will never be sold. Kick myself often for selling my GB2 for pretty much no reason.

Definitely interested in how it performs with Vivi's coarse grit edges.
15 :bug-red 's in 10 different steels
1 - Bradford Guardian 3 / Vanadis 4E Wharnie
1 - Monterey Bay Knives Slayback Flipper / ZDP 189
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Re: Vivi's M4 Manix XL DLC Corrosion Log

#37

Post by vivi »

Another sweaty IWB day for the M4 Manix. I spent about 11 hours being active, going for runs, riding my bike, did some climbing, etc. On a normal day either my Pacific Salt or Siren would have joined me, but I have theories to test :)

Prior to any cleaning:

Image
Image

After the thumb cleaning process:

Image
Image

So, still a big difference in the before and after pictures. But, it isn't wiping as clean today.

All of the uncoated parts are still flawless, such as the tang and the edge of the lock cage.

For the time being I will continue as is.

Eventually I may step up the cleaning process to something more involved, like an oiled rag or a magic eraser. Or even just some hot water and soap. We'll see.

Like I said I'm not afraid of rusting the blade. I have the tools and experience to strip and polish the blade.
Cambertree wrote:
Wed Oct 07, 2020 8:35 pm
Cool. How are you liking the M4 in that platform otherwise? And can you make any general comments and comparisons to your S30V XL model yet?

I bet it would be a beast of a cutter with one of your acute 300 grit diamond/7 μm stropped edges

I get a lot of enjoyment out of M4, it’s definitely in my top 5 favourite steels.

Yeah, I generally don’t worry about the blade rusting either. Where I appreciate the benefits of DLC and stainless cladding are in the pivot and tang area.
I've used M4 in the past and I always appreciated how easily it sharpened for the level of toughness and edge holding it offers. It always struck me as a well balanced steel that offers everything in spades aside from corrosion resistance, obviously. Takes a very keen edge every time I sharpen it.

As for how it performs on my Manix I can't make much of a comment beyond the factory edge. It came screaming sharp, one of the top 5 sharpest factory edges I have ever used. It came with a more polished edge than Spyderco typically runs, feeling perfectly smooth when I run my thumbnail along the apex. It has held that sharpness well the past week. I stropped it 3x per side today with my 7 micron diamond paste and its a little sharper than when new. Pops hairs effortlessly and push cuts receipts.

Despite my love for coarse edges, I have to say this more polished edge has cut things very well, even things more polished edges can struggle with. It just goes toshow that a cleanly apexed knife will be able to simply cut, period. I can slice cooked sausages and thick poly rope no problem with this knife, and I can shave with my 300 grit edges formed off a $12 diamond stone. You don't need a super coarse edge to cut rope (though it will keep cutting rope longer), and you don't need to go above 200-400 grit for shaving sharpness or push cutting paper.
TkoK83Spy wrote:
Wed Oct 07, 2020 8:43 pm
Definitely interested in how it performs with Vivi's coarse grit edges.
I will definitely give it one at some point. I am very curious to compare it head to head to my K390 Police, which is my current king of edge holding. If I had to guess, I'm expecting the M4 blade to take a keener edge, but hold it not quite as long as K390. We'll see.
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Re: Vivi's M4 Manix XL DLC Corrosion Log

#38

Post by Wartstein »

vivi wrote:
Tue Oct 06, 2020 10:18 pm
kobold wrote:
Tue Oct 06, 2020 9:24 pm
I think the spots are simply the dried on salt in your sweat.
That's certainly possible. I know after a long, hot day I have visible salt crystals on my arms, face etc.

Well, dried on salt is certainly a thing when one is active: This is me after a day in the mountains (and not even a particularly hot, but rather cool one in later autumn).. :D

And my knives do have Salt on them either when carried while such activities

Image
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Re: Vivi's M4 Manix XL DLC Corrosion Log

#39

Post by curlyhairedboy »

I wonder if regional microfauna play a role in relative corrosion from sweat, especially close to the body.
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Re: Vivi's M4 Manix XL DLC Corrosion Log

#40

Post by vivi »

October 8th update.

Carried it IWB during some runs and put it away wet and sweaty.

Image

After it dried:

Image

After the usual thumb cleaning:

Image

Seems to be permanently stained now. I will proceed as usual for another week, then try a different cleaning method.
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