ZDP-189 really DOES stain fast

[Murdoc]

Well, I've had the D4 Zdp before, but never really carried it much, partly because of my D4W that kept jumping in my pants :), partly because I was a bit disappointed about the uneven grinding angles on the ZDP Delica and its (lack of) hairpopping sharpness. After some work on the sharpmaker, I sorted that out, but it never grew on me, so I sold it.

But then I decided to give ZDP a 2nd chance, but this time with an Endura. After quite a while, I recieved a well finished, sharp and even grinded E4. I immediately put it in my Jeans RFP and started EDCing it :D

It was really hot at this time, so it was quite humid in my pocket :rolleyes:

after 4-5 hours, I was back home and pulled it out of my pocket, and there were may tiny rust spots all over the visible part of the blade. I was shocked :eek:
I removed the rust by rubbing it off with an oiled cloth. It was more or less allright. So I thought. Since then, I tried to keep the blade slightly oiled at all time (which is not ideal when preparing food :-).

Now, after 2-3 weeks in my EDC rotation along with my new Mili and old Police, the blade looks like this (mind you, AFTER a thorough cleaning and trying to rub the blade off with Nevr Dull and metal polish. This blade is CLEAN). I more or less didn't use it at all, just carried it occasionally.

http://i160.photobucket.com/albums/t194/Murdoc370/CIMG5971.jpg

http://i160.photobucket.com/albums/t194/Murdoc370/CIMG5973.jpg

http://i160.photobucket.com/albums/t194/Murdoc370/CIMG5977.jpg

http://i160.photobucket.com/albums/t194/Murdoc370/CIMG5982.jpg

What do you think about these spots??


Dennis

[The Deacon]

Are those whiteish speckles the locations where the blade rusted? ZDP is very hard stuff, so it would be somewhat understandable that it might be difficult to polish out the edges of the small pits left by the rust.

Beyond that, can only speak from my own experience. Have been carrying a ZDP Caly 3 on and off for several months now, and using it fairly often for food prep. Do not take any particular care of it, try to remember to rinse it off after cutting food with it, sometimes wipe it on my pants leg afterward to get at least some of the water off. Have never seen any sign of rust, or even the grey-brown patina some others have reported developing on ZDP.

[LowTEC]

It doesn't seem like a severe problem YET.

My Leek TiZDP surface rusted big time after I wiped clean it with a not-so-perfectly-clean cloth after cutting lemons. My Caly Jr ZDP on the other hand, has no problem with rust at all, touch wood.

Try to wipe the spot off after soaking it in soda water for couple minutes, that worked for my Leek.

[Murdoc]

It is just cosmetic, and since it's meant to be a user, i don't care too much, but it is still annoying that the knife begins to rust after 4 hrs in my pocket WITHOUT EVEN BEING USED for one single time :mad:

I mean, if I had cut lemon or other acid fruits and then put away without cleaning it or something... or left sitting in some aggressive environment....

but the only thing I did was carry it with me. It didn't even left my pocket and already began to age seriously. I've never encountered that carrying VG-10 or any other steel.... I really thought of this steel to be a bit more durable, aesthetically spoken.

We will see how this problem will develop over time, but truth is, this knife looks well-used already, though it in fact is not. Oh well, so I can be uninhibited in using it hard ;)

[LowTEC]

Like you mentioned, I wouldn't worry too much about the cosmetic problem, ZDP is one heck of supersteel, my Caly Jr held up like nothing else given that with its razor thin edge, I only had to touch up the edge once or twice at most after continuous usage everyday for a month.

[The Deacon]

For whatever little it's worth, I'm of the opinion that a persons body chemistry can be incompatible with some types of steel. Spyderco has had a considerable number of ZDP knives in the field quite a while now. Even factoring in the percentage held by collectors and speculators that have never seen use, I'm inclined to think that if this were a general issue with the steel it would have been reported more often than it has.

[EarthDog]

My ZDP D4 got a spot of rust right after I got it. I polished it out with Flitz, and it left a pit.

[Padawan]

It might also be a worthwhile reminder to mention that steels always involve compromises, and ZDP-189 is still quite corrosion resistant compared to certain other very high-end steels such as M2.

[SimpleIsGood229]

Howdy,

I noticed the same thing with my ZDP Endura. (Yes, I got it, but more on that in a seperate thread.) Mine was in my pocket for a few hours and developed some very light surface rust spots. 102 degrees, 80% humidity Houston, TX summers, ya know! I BreakFree'd it and it's all gone. Looks like new, as far as that goes.

My theory as to why it rusts so easily in comparison to other stainless steels is this: it has a chromium to carbon ratio of 6.67-1* (20% chromium, 3% carbon). VG-10, for example, has a chromium to carbon ratio of right around 15-1*. Even though ZDP has a rediculously high amount of chromium, it also has a stupid-high :cool: amount of carbon. Basically, it has a low chromium to carbon ratio, which explains why it rusts easily in camparison to other stainless steels.

Please, correct me if I'm wrong. I'm just a speculating (question asking) newbie! :)


*This going off of the Spyderco charts.

[The General]

I never got on with ATS-55 rust wise. It just did not like me or my enviroment. However, one knife in ATS-55 was fine...

Not had any rust issues here, I will keep an eye on my ZDP189 blades.

[lycanthought]

I've got a ZDP D4 and I've noticed that it rusts a lot compared to other stainless steels. Now, I've got what is known in the toolmaking trade as "rusty fingers" i.e. my sweat is somewhat salty and I'm prone to leaving rusty fingerprints on stuff. However my VG10 and S30V blades have never seen a hint of a spot. I wouldn't call it stainless in the same way. It's a compromise, more like D2.

[dialex]

Thanks for the thread. Well... I guess I'll have to stick to VG-10 then... :o

[zenheretic]

Thanks for the thread. Well... I guess I'll have to stick to VG-10 then... :o

Indeed, some on the internet have S30V virtually chipping from a stern look, now ZDP rusts from a gentle baby's breath. More VG-10 for me please (oh and a side of H1) ;)

[shu]

Well, go figure - I rotate VG-10 (E4W), S30V (Para), & ZDP (D4) and have actually had more problems with spotting on the VG10... I don't consider myself 'average' though so pay me no mind.

[Michael Cook]

:spyder: Some people have really corrosive sweat. I have a buddy who eats through his clothes, wears out a cap in less than a year. :spyder: