How can you tell if black dlc blades are corroding?

[anycal]

With the pattern that rust took on M4, I am inclined to think there are particles of something on the surface on the blade, rather than the blade itself corroding...

Not sure what that would be? Had this happen few times. I doubt my knife was contaminated with something metalic or corrosion prone each time. Unless the DLC itself is prone to corrosion? I can't see how.

[vivi]

With the pattern that rust took on M4, I am inclined to think there are particles of something on the surface on the blade, rather than the blade itself corroding...

Not sure what that would be? Had this happen few times. I doubt my knife was contaminated with something metalic or corrosion prone each time. Unless the DLC itself is prone to corrosion? I can't see how.

Couldn't tell you what it would be, just thought it was a possibility. Anytime I marked a DLC blade and thought it was corrosion or general wear penetrating the coating, it was something that rubbed off on the surface. My keys would often mark up the Para 2, and before I realized it could rub right off and leave no trace I questioned how good DLC is. Other coatings, like the thick baked on finish low end 1095 camp knives often have, seems to wear dramatically faster.

[Cave_Hermit]

Thanks for all the replies everyone and the links, I just learnt a whole lot of things from reading this thread much appreciated!

[Spyderman91]

I clowned the DLC coating on my PM2 at first, but every time I wash it.. it appears to just eat the blemishes. It looks used yes, but
really you can barely tell... and it still looks very aesthetically pleasing.. just broken in :)

[Tucson Tom]

Here is some scientific article about PACVD aka DLC coatings:
"Amorphous SiOx .....

Amorphous silica is an entirely different material. DLC is carbon. This article has little relevance to the current discussion, apart from the same technology being used to deposit the silica.

[Joey]

I’ll admit I came in with little personal experience, and only word of mouth through this forum. Personally, I imagined the coating had to do something to protect it, but had heard numerous times that it wasn’t capable. Someone even mentioned they heard it from a Spyderco rep.
At this point it’s just like anything else in life; it depends on who you ask.
Lesson learned, I’ll have to wait on my own experience with DLC before stating what I think are facts.
Didn’t mean to interrupt though, carry on! Interesting information here.

[Mystery Flavor]

There is so much bad information about knife blade coatings out there. And i rarely see people provide any evidence or talk from their own experience. People are just repeating each other like monkeys. Not all blade coatings are created equal and maybe people had bad experience with fake or bad DLC from other companies. But Spyderco uses the best coatings. The DLC is bonded to the steel at molecular level, unlike many other coatings.

Michael Janich from Spyderco has posted about DLC coatings several times:
//forum.spyderco.com/viewto ... 94#p895794
//forum.spyderco.com/viewto ... 18#p878418
//forum.spyderco.com/viewto ... 48#p589348

Here is some scientific article about PACVD aka DLC coatings:
"Amorphous SiOx films provide excellent corrosion protection of steel, which is explained, on the one hand, by a tiny porosity rate, and on the other hand, by intrinsic insulating properties of the coating. This barrier effect avoids any galvanic coupling deleterious to the uncoated metallic surface, and is correlated with the SiO2-like character of the film."

Thanks for all the info shared on this thread. I appreciate those links to Janich's older posts about this!

It's impressive how durable the DLC coatings are. If the rust can creep up underneath the DLC from the edge grind or other scratches then wouldn't it eventually spread entirely and then the DLC coating wouldn't be actually attached to anything other than rust at that point?? I just can't imagine that ever happening and it's very hard to imagine the rust creeping far under DLC, but I certainly could be wrong. I'd love to see some tests with photos or video trying to conclusively show what will consistently happen to DLC coated blades if left in terrible corrosive conditions for a long time.

Also what about some of the similar coatings like the PVD used on the recent River's Edge Cutlery Para 3? It would be cool to find out if there are any noticeable benefits or weaknesses to this and similar coatings that haven't been used by spyderco as much as DLC.

Does anyone know if DLC or other coatings could ever have any potential to leach chemicals out into food that is cut with it? Just figured this is a decent place to ask.

I can't help but wonder what the future will hold for new coatings not yet developed... It would also be cool to see the Japan models be offered with a DLC coating or other varieties along with the TiCN they currently use.

[curlyhairedboy]

For sure this isn't a 1:1 comparison, but:

my Taichung-made Spyderco Advocate developed a tenacious patina, widespread spotting and the beginnings of pitting despite an aggressive maintenance schedule. Never saw wet use, just lived in my pocket as I worked in the garage.

my DLC M4 PM2, made in Golden, has shown perhaps a light freckling that wipes away with my usual application of protectant, on a timetable much less aggressive than the advocate enjoyed. This despite living in the same pocket conditions.

[blues]

my DLC M4 PM2, made in Golden, has shown perhaps a light freckling that wipes away with my usual application of protectant, on a timetable much less aggressive than the advocate enjoyed. This despite living in the same pocket conditions.

This makes me happy to read as I live in a fairly rainy and humid environment and the DLC M4 PM2 has become a real favorite since its arrival a week or two back. (I'm pretty good about maintaining my gear in any case, but nonetheless, the reports of DLC blades holding up to the elements is heartening.)

[Cave_Hermit]

I've never carried any coated DLC blades on the kayak so I don't have any first hand data. About 5 or 6 years ago though, I sold a coated pm2 to a friend who is a boat captain in the marina here. He is out on fishing charters every day and the knife sees a LOT of saltwater. About a year after he bought it he asked me if I would sharpen it. I noticed a few light rust spots blooming on the coating itself, same as they would be on an uncoated blade. I assumed at the time that the underlying steel was rusting but now I really wish I had paid more attention. It could be the steel rusting under the coating or it could be the hardware showing some rust and bleeding onto the blade as can happen in HIGHLY corrosive environments. I will make a point of asking him if he still has the knife so I can make a proper inspection. I am interested now.

I’m very interested for your results mate.

[Brown_Recluse]

Is there a certain technique (or lubricant/protectant) to protect a blade with DLC? In my experience, when I use oil on a DLC'd blade it just makes the blade look splotchy and gunked up. Is this just unavoidable?

[blues]

Is there a certain technique (or lubricant/protectant) to protect a blade with DLC? In my experience, when I use oil on a DLC'd blade it just makes the blade look splotchy and gunked up. Is this just unavoidable?

It seems to be the case when I wipe it down with a light coat of mineral oil. (Sort of like when lubricating an oil stone. The "swarf" seems to rise to the top.)

I just barely moisten my fingertips, rub a bit into the coating and then wipe it gently. That seems to leave a bit of protection without feeling gunked up. YMMV. (I haven't used synthetic oil or CLP or any other stuff I use on knives or firearms.)

[Brown_Recluse]

Is there a certain technique (or lubricant/protectant) to protect a blade with DLC? In my experience, when I use oil on a DLC'd blade it just makes the blade look splotchy and gunked up. Is this just unavoidable?

It seems to be the case when I wipe it down with a light coat of mineral oil. (Sort of like when lubricating an oil stone. The "swarf" seems to rise to the top.)

I just barely moisten my fingertips, rub a bit into the coating and then wipe it gently. That seems to leave a bit of protection without feeling gunked up. YMMV. (I haven't used synthetic oil or CLP or any other stuff I use on knives or firearms.)

I'll have to try that. I don't even own mineral oil but I do have a plethora of household and firearm/knife lubes. I think I tried 3-in-1, Hoppes #9 and Hoppes Elite Gun Oil on my DLC PM2 and I didn't like the result. Luckily some hot water and Dawn took it off.

Now that I have this 4V DLC Para 3 I'm much more inclined to find a way to protect it whereas with s30v it wasn't really necessary.

[Fixmeister]

Flitz to remove marks... so, is the DLC resistant to the polish of Flitz? I was concerned that any polishing agent would begin to remove the DLC itself. And out of curiosity, did the Flitz put a shine on the DLC? My Para 3 M4 has a flat DLC and I’ve seen DLC with a satin finish. Might be something I’d try to get a bit of a sheen on the blade. Maybe a Fabulustre cloth with jewelers rouge on it?

[blues]

I'll have to try that. I don't even own mineral oil but I do have a plethora of household and firearm/knife lubes. I think I tried 3-in-1, Hoppes #9 and Hoppes Elite Gun Oil on my DLC PM2 and I didn't like the result. Luckily some hot water and Dawn took it off.

Now that I have this 4V DLC Para 3 I'm much more inclined to find a way to protect it whereas with s30v it wasn't really necessary.

A couple bucks for a pint at Wally world:

[Evil D]

Flitz to remove marks... so, is the DLC resistant to the polish of Flitz? I was concerned that any polishing agent would begin to remove the DLC itself. And out of curiosity, did the Flitz put a shine on the DLC? My Para 3 M4 has a flat DLC and I’ve seen DLC with a satin finish. Might be something I’d try to get a bit of a sheen on the blade. Maybe a Fabulustre cloth with jewelers rouge on it?

I haven't had to be so aggressive with Flitz that it actually polished the DLC, but I do strop my serrations with a Dremel cotton wheel loaded with polishing compound and I have seen the finish take on a shinier look near the edge. I think if you just use Flitz on a rag with your finger you'll be fine. Afterwards wipe the blade down with alcohol and then with mineral oil and it'll be good to go.

[jpm2]

The rust still looks like rust, but it is fairly easy to remove in my experience.

My M4 DLC PM2 was my EDC outside of the office since it dropped until the REX45 dropped (which took it's role so far). It was my yard work/project/camping/hiking beater. I treat my knives like knives, but I didn't go out of my way to baby it.

Here is what it looked like this morning:




Fortunately, it is easy to rub most of the rust off with 5mins or less of elbow grease.




This has been my experience with Spyderco's DLC on the S30v model as well, FWIW. Hope this helps.

If there's any tiny pits where the rust was, I think it was the blade. If it's perfectly smooth, I'd say it was surface contamination.

[vivi]

Is there a certain technique (or lubricant/protectant) to protect a blade with DLC? In my experience, when I use oil on a DLC'd blade it just makes the blade look splotchy and gunked up. Is this just unavoidable?

DLC is the protection

[The Mastiff]

DLC is the protection

Yes.

If you are really in an area with corrosion problems waxing or putting chapstick or something on the edge is a good idea when not using the knife for a while. Cutting stuff will prevent the edge from getting too bad for a time.

Joe

[Cave_Hermit]

Is there a certain technique (or lubricant/protectant) to protect a blade with DLC? In my experience, when I use oil on a DLC'd blade it just makes the blade look splotchy and gunked up. Is this just unavoidable?

I used marine tuff cloth on my coated S3OV para 2 which was a bit overkill :D and it made the coating look grey but a wipe with wd40 made it nice and black/sleek looking again.