Page 1 of 2
What is more resistant to rust - DLC'ed carbon steel or plain stainless?
Posted: Wed Feb 13, 2019 6:07 am
by youmakemehole
Just what the title says – for those who have had the opportunity to test out their DLC's and stainless blades in more humid/corrosive environments, would a carbon steel with Spyderco's DLC or a stainless steel with no coating be less prone to corrosion and rust?
In case the question is too vague, this info would be for my specific case comparing DLC M4 against CTS-204, both on the PM2.
Re: What is more resistant to rust - DLC'ed carbon steel or plain stainless?
Posted: Wed Feb 13, 2019 8:47 am
by vivi
For me, definitely DLC coated carbon steel.
This is one of the reasons I keep asking for DLC runs of carbon steels on folders. The biggest drawback of these steels in folding knives is moisture etc. can easily get trapped in the pivot area. No matter how diligent you are at wiping down the blade, you can't wipe the pivots dry, which is where rust will surely develop over time.
DLC is a game changer when it comes to corrosion resistance. My DLC Manix XL has seen a few years of use now without a single speck of rust anywhere. I've used plain S30V blades for over a decade and I've managed to rust pretty much all of them somewhere, even my Swick. Going two years without ANY rust? I have never, ever had a folding knife do that for me unless it was a salt.
Bear in mind the uncoated edge is still just as susceptible to rust as plain carbon steel, so you'll want to be careful about keeping it wiped clean and making sure its dry when it goes in your pocket.
Another tip is running a polished bevel on these steels. The higher a polish, the harder it is for rust to form. You'll still get a patina and discoloration, but there won't be tons of grooves for things to get trapped in and speed up rust development. You can still run a toothy microbevel if you prefer a lower grit edge like I do.
Re: What is more resistant to rust - DLC'ed carbon steel or plain stainless?
Posted: Wed Feb 13, 2019 9:00 am
by JonLeBlanc
I'm not sure I have much input because I don't own any dlc coated knives, but that sure is a good question! In my experience M4 is not a total rust magnet like the 52100 which I adore, so that makes for a good comparison between something like M390.
Re: What is more resistant to rust - DLC'ed carbon steel or plain stainless?
Posted: Wed Feb 13, 2019 9:12 am
by Larry_Mott
Can't really give an educated answer as i avoid DLC if i can. I think it looks cheap.. I do shower though!
(And i can't believe how some people have knives rust on them by seemingly subjecting them to raw air.. There's not a speck so far on my Superblue Calypso Jr i have carried daily for a couple of months, not even a shade of patina. Either i got a magic one, or a mis-labeled one, that is really a totally different steel :)
Re: What is more resistant to rust - DLC'ed carbon steel or plain stainless?
Posted: Wed Feb 13, 2019 9:38 am
by cycleguy
I was handed a used Kabar USMC 7" Fighting Knife the other day to mess around with. It has a black coating (of what?) over the blade which is 1095. There is no rust on the black coating but the exposed edge and scratched areas in the coating are covered in rust.
I've been working it back to shape with a clamp type sharpening system and a diamond rod for the serrated portion of the blade. I'm finding more (thicker) blade stock on one side near the tip which has caused the bevel to grow twice that on the other side of the knife. I know it is an inexpensive knife but I would appreciate a USA made product being more consistent with its workmanship.
One other thing I noticed is if the sharpening stone drops below the bevel, the blade coating mars very easily and well you just messed up the looks of that coating, ouch!
For these two reasons, I'm leaning away from coated blades as the un-coated blades are a bit more forgiving to manufacturing inconsistency and sharpening errors.
Live and learn,
CG
Re: What is more resistant to rust - DLC'ed carbon steel or plain stainless?
Posted: Wed Feb 13, 2019 9:44 am
by vivi
Larry_Mott wrote: ↑Wed Feb 13, 2019 9:12 am
Can't really give an educated answer as i avoid DLC if i can. I think it looks cheap.. I do shower though!
(And i can't believe how some people have knives rust on them by seemingly subjecting them to raw air.. There's not a speck so far on my Superblue Calypso Jr i have carried daily for a couple of months, not even a shade of patina. Either i got a magic one, or a mis-labeled one, that is really a totally different steel :)
Where do you live? I'm somewhere that has high humidity year round and 75-85F days in January / February :p
Re: What is more resistant to rust - DLC'ed carbon steel or plain stainless?
Posted: Wed Feb 13, 2019 10:08 am
by Sjucaveman
Lc200n is the answer
Re: What is more resistant to rust - DLC'ed carbon steel or plain stainless?
Posted: Wed Feb 13, 2019 10:25 am
by cycleguy
Sjucaveman wrote: ↑Wed Feb 13, 2019 10:08 am
Lc200n is the answer
Don't believe it retains its edge as well as the two referenced steels.
CG
Re: What is more resistant to rust - DLC'ed carbon steel or plain stainless?
Posted: Wed Feb 13, 2019 10:29 am
by cycleguy
Would like to ask... "if patina and discoloration is ok for the working edge, why isn't it ok for the entire blade?
CG
Re: What is more resistant to rust - DLC'ed carbon steel or plain stainless?
Posted: Wed Feb 13, 2019 10:40 am
by The Deacon
IMHO, the edge is really the only part of the blade where rust is anything more than a cosmetic issue. On a DLC coated blade, the edge will either not be coated, or the coating will come off the edge the first time you sharpen the knife. For that reason, I'd have to go with plain stainless.
Re: What is more resistant to rust - DLC'ed carbon steel or plain stainless?
Posted: Wed Feb 13, 2019 10:42 am
by Larry_Mott
Vivi wrote: ↑Wed Feb 13, 2019 9:44 am
Larry_Mott wrote: ↑Wed Feb 13, 2019 9:12 am
Can't really give an educated answer as i avoid DLC if i can. I think it looks cheap.. I do shower though!
(And i can't believe how some people have knives rust on them by seemingly subjecting them to raw air.. There's not a speck so far on my Superblue Calypso Jr i have carried daily for a couple of months, not even a shade of patina. Either i got a magic one, or a mis-labeled one, that is really a totally different steel :)
Where do you live? I'm somewhere that has high humidity year round and 75-85F days in January / February :p
I live in Helsingborg, right by the seaside. Humidity is rather low over here though, especially during winter.
https://www.google.com/maps/@56.0461402 ... 572,11.66z
Re: What is more resistant to rust - DLC'ed carbon steel or plain stainless?
Posted: Wed Feb 13, 2019 11:02 am
by vivi
Looks like you guys see some warm weather in the summer. Where I live we have your summer weather pretty much year round. It's rare to see it dip under 60F during the day regardless of which time of year it is.
cycleguy wrote: ↑Wed Feb 13, 2019 10:29 am
Would like to ask... "if patina and discoloration is ok for the working edge, why isn't it ok for the entire blade?
CG
Patina and discoloration is one thing, rust and pitting is another. The former is generally a good thing, and helps protect carbon steels from corrosion. Rust and pitting can damage the blade in various ways.
It's not purely cosmetic. Rusted pivots get extremely tight and gritty. Rusty liners can spread rust to blades, and in turn cause pitting.
Re: What is more resistant to rust - DLC'ed carbon steel or plain stainless?
Posted: Wed Feb 13, 2019 11:17 am
by wrdwrght
The Deacon wrote: ↑Wed Feb 13, 2019 10:40 am
IMHO, the edge is really the only part of the blade where rust is anything more than a cosmetic issue. On a DLC coated blade, the edge will either not be coated, or the coating will come off the edge the first time you sharpen the knife. For that reason, I'd have to go with plain stainless.
This.
Re: What is more resistant to rust - DLC'ed carbon steel or plain stainless?
Posted: Wed Feb 13, 2019 11:22 am
by cycleguy
Vivi wrote: ↑Wed Feb 13, 2019 8:47 am
For me, definitely DLC coated carbon steel.
This is one of the reasons I keep asking for DLC runs of carbon steels on folders. The biggest drawback of these steels in folding knives is moisture etc. can easily get trapped in the pivot area. No matter how diligent you are at wiping down the blade, you can't wipe the pivots dry, which is where rust will surely develop over time.
DLC is a game changer when it comes to corrosion resistance. My DLC Manix XL has seen a few years of use now without a single speck of rust anywhere. I've used plain S30V blades for over a decade and I've managed to rust pretty much all of them somewhere, even my Swick. Going two years without ANY rust? I have never, ever had a folding knife do that for me unless it was a salt.
Bear in mind the uncoated edge is still just as susceptible to rust as plain carbon steel, so you'll want to be careful about keeping it wiped clean and making sure its dry when it goes in your pocket.
Another tip is running a polished bevel on these steels. The higher a polish, the harder it is for rust to form. You'll still get a patina and discoloration, but there won't be tons of grooves for things to get trapped in and speed up rust development. You can still run a toothy microbevel if you prefer a lower grit edge like I do.
Vivi,
Your last paragraph... is what I saw on the referenced knife in my prior post. Deepest portions of the scratch pattern were full of rust. I observed this under 10x magnification. Looked like someone had used a course sanding disk on the knife's edge somewhere in its past.
Guys, don't worry about me skewing the results of the survey. I voted "don't shower".
CG
Re: What is more resistant to rust - DLC'ed carbon steel or plain stainless?
Posted: Wed Feb 13, 2019 11:38 am
by vivi
The Deacon wrote: ↑Wed Feb 13, 2019 10:40 am
IMHO, the edge is really the only part of the blade where rust is anything more than a cosmetic issue. On a DLC coated blade, the edge will either not be coated, or the coating will come off the edge the first time you sharpen the knife. For that reason, I'd have to go with plain stainless.
If a blades pivot rusts to the point it takes 50lbs of force to open the knife, is that a cosmetic issue? :)
Re: What is more resistant to rust - DLC'ed carbon steel or plain stainless?
Posted: Wed Feb 13, 2019 11:58 am
by ferider
Vivi wrote: ↑Wed Feb 13, 2019 8:47 am
For me, definitely DLC coated carbon steel.
This is one of the reasons I keep asking for DLC runs of carbon steels on folders. The biggest drawback of these steels in folding knives is moisture etc. can easily get trapped in the pivot area. No matter how diligent you are at wiping down the blade, you can't wipe the pivots dry, which is where rust will surely develop over time.
DLC is a game changer when it comes to corrosion resistance. My DLC Manix XL has seen a few years of use now without a single speck of rust anywhere. I've used plain S30V blades for over a decade and I've managed to rust pretty much all of them somewhere, even my Swick. Going two years without ANY rust? I have never, ever had a folding knife do that for me unless it was a salt.
I would agree that DLC stainless is probably the most rust-resistant (as your DLC S30V knive, or my DLC S90V). But that wasn't the question I thought. I think the jury on rust-resistance of DLC carbon steel (M4, 52000, etc) is still out. There are good chemical arguments that DLC doesn't make much difference, a DLC blade can scratch, and Spyderco doesn't give a solid statement either. For simple marketing arguments, they would say so, if there was evidence that DLC helps much in corrosion resistance.
So, for corrosion resistance, plain 204p over DLC M4 any day for me. Plus I prefer how a plain knife "feels". :)
Roland.
Re: What is more resistant to rust - DLC'ed carbon steel or plain stainless?
Posted: Wed Feb 13, 2019 12:47 pm
by vivi
I've used lots of coated carbon steel blades with similar results as the Manix.
Re: What is more resistant to rust - DLC'ed carbon steel or plain stainless?
Posted: Wed Feb 13, 2019 3:51 pm
by youmakemehole
Sjucaveman wrote: ↑Wed Feb 13, 2019 10:08 am
Lc200n is the answer
Oh trust, if PM2's came in LC200n you wouldn't have to be bothered by my thread. I have multiple knives in LC200n and I also am fully aware that LC200 as well as coated stainless blades will perform far better against corrosion than the options I'd laid out earlier. There is a reason why I asked what I did and it is because I have a PM2 in CTS204 and another in M4+DLC, I am trying to pair them with a G10 handle and a peel-ply CF handle, and I'd like the more corrosion resistant blade out of the two to go on the peel ply as it will be the go-to PM2 I will take out on rainy days, the beach, camping trips, etc as I think I'd prefer the peel ply slightly more for wet and all-round use. If I knew the knife would get straight drenched I'd probably go with one of my LC200 or stainless folders but otherwise a PM2 sometimes just feels kinda right ya know what i mean? I do have a Spydiechef in transit to my mailbox right now though and truth be told it has been a while since I've been this excited for a knife :p
Vivi wrote: ↑Wed Feb 13, 2019 8:47 am
For me, definitely DLC coated carbon steel.
...
Appreciate the thought out response, lots of relevant info here for me so thank you!
Re: What is more resistant to rust - DLC'ed carbon steel or plain stainless?
Posted: Wed Feb 13, 2019 4:10 pm
by youmakemehole
The Deacon wrote: ↑Wed Feb 13, 2019 10:40 am
IMHO, the edge is really the only part of the blade where rust is anything more than a cosmetic issue. On a DLC coated blade, the edge will either not be coated, or the coating will come off the edge the first time you sharpen the knife. For that reason, I'd have to go with plain stainless.
Wouldnt you think that with a little bit of use, any moisture or even rust that develops on the edge would be quickly rubbed off? It would only need to be lightly used say maybe once every 1-2 days even in the most humid conditions to fully get rid of anything that could potentially develop.
ferider wrote: ↑Wed Feb 13, 2019 11:58 am
I would agree that DLC stainless is probably the most rust-resistant (as your DLC S30V knive, or my DLC S90V). But that wasn't the question I thought. I think the jury on rust-resistance of DLC carbon steel (M4, 52000, etc) is still out. There are good chemical arguments that DLC doesn't make much difference, a DLC blade can scratch, and Spyderco doesn't give a solid statement either. For simple marketing arguments, they would say so, if there was evidence that DLC helps much in corrosion resistance.
So, for corrosion resistance, plain 204p over DLC M4 any day for me. Plus I prefer how a plain knife "feels". :)
Roland.
I can relate, it almost seems to me that a plain blade can be kept cleaner/dryer more easily if you are just a tad bit mindful whereas on something coated, you can develop more nooks and crannies where moisture can stay hidden from a simple swipe of a drying cloth or tshirt, whether thats correct or not, I dont know, but with my experience with bikes and bike parts, scratched parts that are painted vs scratched parts that are only raw/polished tend to rust more easily. Perhaps DLC could be better if you never bother to even dry the blade after it gets wet though? And then theres the question of the pivot, which pivot would be fare better in the wet, I think is the question now at this point with most other bases covered already in the thread.
Re: What is more resistant to rust - DLC'ed carbon steel or plain stainless?
Posted: Wed Feb 13, 2019 4:55 pm
by wrdwrght
youmakemehole wrote: ↑Wed Feb 13, 2019 4:10 pm
even rust that develops on the edge would be quickly rubbed off?
While rust that is “rubbable” off the broader surface of a blade may not be especially concerning, rust that is “rubbable” at the apex is truly worrisome.
Why? Ask yourself what is being rubbed off.
Sal has alluded to the chemically-reactive nature of certain steels along their apex. And I can support this idea anecdotally.
Decades ago, I gave up my straight-razor (some Solingen steel) and packed it away in its box in the bathroom. Countless humidity cycles Iater, I pulled out the razor for a walk down memory lane last year. The thing had rust everywhere. I was able to get the rust off all of the razor (stains have remained) but steel has been lost on the apex such that the edge looks badly chipped.
DLC does not address this problem. Even if you don’t suffer “chipping”, you’re gonna get dull but quick.