Police4 K390 in the hot Summer.

[Jeb]

Ok here is a Police4 in K390 and it has been Flitz several times and rag wheel buffed with Fabuluster compound and this is what we get in our hot sweaty pockets while it's hot and humid here in Texas... One week time frame.

This is an awesome knife, we just get this in the DLC and some new steel so it stays sharp and clean from all this rust, we would really have something then.

The knife is still sharp, but it needs to be honed, it's had a really long hard week. The EDC Extraordinaire knife of choice... just really need this in a steel that you can sharpen to a fine razors edge and it keep that edge like K390, but not so bad to rust out in your pocket here in the Texas summers, and oh heck yes, it's doing hardtime. We're talking this knife sees way hard time...

[RustyIron]

A knife that's been used, a truck bed that's been used, and a new pair of gloves.
Two out of three ain't bad!

[Bill1170]

DLC would be a wonderful addition to K390 blades.

[Jeb]

Yes the gloves are new lol, I hate breaking in these new devils too. But these Tillmans are great gloves.

DLC to the K390 is something I do have another less used K390 Police4 I have talked to a guy about doing the DLC coating to. I just have not took the knife apart and send it to him.

I have no excuses why I have not sent him this knife either. I have quite a few of these Police4 I want to have the K390 blade DLC'd if this first one works right.

I am hoping this posting of this one will get me in gear and send him my blade to get coated. I get really busy here in the summer but I need to make time to do this.

[Evil D]

I carried this Ladybug on my keys for 3 weeks and this was the result.



My keys hang from a steel ring on my belt, so they're not in my pocket close to body moisture. Where I work gets around 100 degrees in the summer and stays at a very high humidity. Even though I spend 90% of my day inside an air conditioned office, just walking out into that hot/humid air was enough to cause this rust. AND this is after drowning the whole knife in Tuf-Glide. The only thing I've ever cut with this knife was pepperoni and only on one occasion, which you'd think being as greasy as it is would do more to help prevent corrosion than cause it. Maybe that's what caused this, I did wipe it clean afterwards but I didn't reapply Tuf-Glide.

Personally this really doesn't bother me much, as long as the pivot stays clean I can polish off most of this rust. What bothers me more is how corrosion will also dull your edge so if I continue carrying this one I'd want to touch up the edge more regularly.

To be fair to K390, I had the same thing happen to a ZDP Ladybug, though not quite as bad and nowhere near as fast.

[Paul Ardbeg]

Magnamax should be close to K390 from an edge retention perspective if i'm not mistaking? Not sure if we will see that on the Police....

[Jeb]

Well I got this cleaned up much as I could, then this one gets honed to 17 dps. It's truly a Razor right now, just not as shiny as I would like it, but that corrosion I can't get off is way down in the porosity of the blade.

I lubed this up with Frog Lube and it's all ready to go.

[zhyla]

Corrosion is bad for edge retention. You might actually come out ahead with a VG-10 or S30V blade. I think you may have made the wrong trade off.

[zuludelta]

Ok here is a Police4 in K390 and it has been Flitz several times and rag wheel buffed with Fabuluster compound and this is what we get in our hot sweaty pockets while it's hot and humid here in Texas... One week time frame.

This is an awesome knife, we just get this in the DLC and some new steel so it stays sharp and clean from all this rust, we would really have something then.

The knife is still sharp, but it needs to be honed, it's had a really long hard week. The EDC Extraordinaire knife of choice... just really need this in a steel that you can sharpen to a fine razors edge and it keep that edge like K390, but not so bad to rust out in your pocket here in the Texas summers, and oh heck yes, it's doing hardtime. We're talking this knife sees way hard time...

The Police 4 LW in PD#1 & Burgundy FRN with a black TiCN coating should still be available at some retailers despite being a Sprint. It isn't DLC'ed K390, but it's a reasonable stand-in IMHO (PD#1 is Carpenter Technology's version of CPM Cru-Wear). And it should hold up better against corrosion (Cru-Wear can almost qualify as a "semi-stainless steel").

There are at least 2 retailers local to me here in British Columbia that still have it, so I imagine there are way more of them still available in the US.

[sal]

I too, learned the hard way about K390 and high humidity areas. Started to rust my K390 P4 sample even before I could get it out of the box to carry. Requires a lot of care and feeding if used in high humid areas.

sal

[JMM]

FWIW, I have found keeping a super thin layer of mineral oil on my K390 (and similarly sensitive tool steel) blades is all that's required to keep almost them like new, it's food safe, doesn't go bad/rancid, is easily sourced, cheap, and actually makes cleanup easier. I started that practice on my first G10 K390 blade then moved on to other tool steels (and XHP) and it's been a wonderful way to keep my blades darn near like new (from a corrosion perspective) & I live where it's humid, wet, or both pretty much all year. Good luck, K390 is fantastic, and the OG G10 P4 is still (IMO) one of the best knives Spyderco or any company has ever made.

......Cheers,

................John

[Jeb]

I have to thank you all for the responses on this. I do have quite a few of the PD #1 Police4 here. I can think of five right off the top of my head, might be another or two still in the box or in one of my trucks I can't think of.

I do think they are a great choice for us here in the Summer. I just always get to busy and let the corrosion get ahead start before I bring out something else and clean this up and frog lube it, then park it for a few months.

What I am most curious about is how well the DLC will address the corrosion on the K390 and even more importantly; will the process the K390 blade will go through getting the DLC affect its ability to retain the keen razors edge that it does so well...

I am going to send this other Police4 in K390 that I have that has not been allowed to get the corrosion started on it; in to this place on the east coast that does the DLC.

Only sending one blade this time to have this done, in case something not being so desirable ends up happening. My biggest concern is the how well the blade still holds its sharp edge after the DLC process.

I know this process requires a heated process, that may very well ruin what we all love about the K390...I just got to tear down this Police4 and send this place the blade and let them do the process and get it back and we will soon know if this works for the knife, or if it makes a letter opener out of it lol.

[vivi]

my blade did ok but for some reasons the liners on my g10 version got wrecked a lot faster than the blade.

The weather is beginning to cool off so I thought I'd get my Police 4 ready to go back into rotation.

I stopped carrying it months ago because I noticed the liners corroding.

Here's what it looks like prior to being cleaned up:

























The knife was carried fall 2018 to spring 2019.

I'm glad a stainless Police 4 is right around the corner.

that was from carrying it late fall to early spring too mind you.

it's pretty hot and humid where I live....many 100F+ days.

[vivi]

Ok here is a Police4 in K390 and it has been Flitz several times and rag wheel buffed with Fabuluster compound and this is what we get in our hot sweaty pockets while it's hot and humid here in Texas... One week time frame.

This is an awesome knife, we just get this in the DLC and some new steel so it stays sharp and clean from all this rust, we would really have something then.

The knife is still sharp, but it needs to be honed, it's had a really long hard week. The EDC Extraordinaire knife of choice... just really need this in a steel that you can sharpen to a fine razors edge and it keep that edge like K390, but not so bad to rust out in your pocket here in the Texas summers, and oh heck yes, it's doing hardtime. We're talking this knife sees way hard time...

The Police 4 LW in PD#1 & Burgundy FRN with a black TiCN coating should still be available at some retailers despite being a Sprint. It isn't DLC'ed K390, but it's a reasonable stand-in IMHO (PD#1 is Carpenter Technology's version of CPM Cru-Wear). And it should hold up better against corrosion (Cru-Wear can almost qualify as a "semi-stainless steel").
C07BGBKP4x.png
There are at least 2 retailers local to me here in British Columbia that still have it, so I imagine there are way more of them still available in the US.

the liners are uncoated fyi.

also cruwear isn't corrosion resistant at all. my temperance rusted from being carried on a ~2 hour hike in the rain.





Really hoping we get a Police Salt someday.

Even the most corrosion resistant Police out there, the VG10 lightweight, I can see rust spots after a single afternoon of carry on a hot summer day where I'm active.

I pretty much have stuck to two knives this summer. Military 2 Salt and CS Recon folder. Both hold up well to corrosive environments. Haven't seen a speck of rust on my magnacut yet and the edge holding is definately an improvement over h1.

The Police is my favorite spyderco folder but my pd1/g10 Police is taking the summer off. I've learned the hard way it's better to just carry a salt than have to sand rust out of liners every 6 months.

[Cletus]

I am curious if anybody here in the humid states has tried Renaissance Wax?

[dsvirsky]

Many, many years ago, Wayne Goddard wrote an article for Blade magazine about his test of the effectiveness of a variety of rust preventatives on carbon steel. Briwax came in first, Ren wax second.

[Pacu0420]

I carried this Ladybug on my keys for 3 weeks and this was the result.



My keys hang from a steel ring on my belt, so they're not in my pocket close to body moisture. Where I work gets around 100 degrees in the summer and stays at a very high humidity. Even though I spend 90% of my day inside an air conditioned office, just walking out into that hot/humid air was enough to cause this rust. AND this is after drowning the whole knife in Tuf-Glide. The only thing I've ever cut with this knife was pepperoni and only on one occasion, which you'd think being as greasy as it is would do more to help prevent corrosion than cause it. Maybe that's what caused this, I did wipe it clean afterwards but I didn't reapply Tuf-Glide.

Personally this really doesn't bother me much, as long as the pivot stays clean I can polish off most of this rust. What bothers me more is how corrosion will also dull your edge so if I continue carrying this one I'd want to touch up the edge more regularly.

To be fair to K390, I had the same thing happen to a ZDP Ladybug, though not quite as bad and nowhere near as fast.

I have a k390 Endela that I used to cut a steak while camping. Apparently steak juice will immediately patina k390. It was kinda ugly. I coated the blade with 3 in 1 oil and let it sit for a couple days. When I wiped it off the stains had just about disappeared.

It just made me think of this when you mentioned cutting pepperoni

[TimButterfield]

I am curious if anybody here in the humid states has tried Renaissance Wax?

I have some of that and have been meaning to try it. Thanks for the reminder.

[Coastal]

I'm sure it's been discussed, but does anyone know how Spyderco decides which knives/steels get DLC. To me it seems random, but there has to be some decision-making going on...

[zuludelta]

I'm sure it's been discussed, but does anyone know how Spyderco decides which knives/steels get DLC. To me it seems random, but there has to be some decision-making going on...

No insider knowledge, but from what I've seen, only Golden models get blacked-out DLC variants. Seki City & Taichung model blacked-out variants get a TiCN coating, and Chinese blacked-out variants get the black oxide treatment. I'm not sure that I've ever seen a blacked-out Maniago Spyderco, but if there was one, I'd bet it would be using the "black idroglider" coating seen on blacked-out folders made by Fox Knives and MKM. I imagine these options are dictated by what is readily & locally available to the respective factories.

I also remember reading that some steels' temper can be affected by the DLC application process, but I don't know any specifics (I do vaguely recall reading somewhere that S30V & MagnaCut aren't particularly subject to this effect, while Elmax is, but don't quote me on that, I'm probably remembering it wrong).