Interesting ZDP-189 Observation

[Dean Crail]

I am a big fan of Spydercos ZDP-189 it is a phenomenal steel at a great price. One if the steels selling points is its high rockwell rating it can take after it has been properly heat treated meaning that it will hold an edge for an exceptionally long time (with the trade off being it is more brittle). The Rockwell on Spydercos is not easy to find for the most part and I was curious as to just how hard Spyderco treated it (Say to Rocksteads 67).

It just so happens that one of my tool and die maker friends has access to a hardness testing machine and offered to test it for me. Turns out it was right at 64.5 rockwell which is part of the reason everyone is getting such good edge retention out of this amazing steel. I look forward to more spyderco offerings in this particular steel!!

 

[Liquid Cobra]

Never doubted it for a minute

Thanks for sharing your findings!

 

[whp]

Thanks for the info on the Rc measurement on your zdp 189 Delica. i ve always thought Spydercos with zdp steel were great bargains. Particularly the earlier models.

 

[tap78]

My endura ffg zdp-189 got in measurements 62.5 HRC but the diamond tip of the meter hit the R letter in blade markings. (I think that spot can be a little bit softer due the laser engraving. I did not have a second chance to measure ;(

 

[carbonsteelfan]

I own an endura in ZDP-189. One of the best edge holders. But no other knife has ever given me a greater difficulty in Sharpening it. It's Damn hard ! Unless you have access to motorized sharpening equipment.

 

[harronek]

I wonder I'd Spyderco heat treats different models to different hardness ?
In my totally uneducated and unscientific assessment of my three ZDP Spydercos the laminated Caly 3.5 blade is more prone to micro chipping than my Delica and DF2 .

Ken

 

[The Deacon]

I wonder I'd Spyderco heat treats different models to different hardness ?
In my totally uneducated and unscientific assessment of my three ZDP Spydercos the laminated Caly 3.5 blade is more prone to micro chipping than my Delica and DF2 .

Ken

Might just be due to the fact that the Caly 3.5 is made by a different maker than the Delica and Dragonfly making it less likely they are all heat treated by the same company. Or it might just be that laminated ZDP-189 requires a different heat treatment from solid ZDP-189. It could also be that the two makers grind to different thicknesses "behind the edge" rather than being a factor of heat treatment. Moki has a well deserved rep for building "pocket scalpels". It could even be some combination of the above. Or, as you noted, it could simply be observer bias.

 

[ZuluKilo]

Dean...awesome post, Brother! Cool to see proof of what so man of us have wondered about and others 'knew'. I had no idea what a Rockwell Hardness test looked like, so double bonus for me!

...But no other knife has ever given me a greater difficulty in Sharpening it. It's Damn hard ! Unless you have access to motorized sharpening equipment.

Carbon, I held off for a long time before purchasing something in ZDP out of fear this happening to me. Sheepishly, I picked up an Endura. But, I haven't found it nearly as hard to sharpen as I had worried. I'm an EP user and my first experience with ZDP was on my buddy's Stretch. It didn't come out as well as I had hoped, but it was more a result of my lack of EP experience at the time than the steel. Since then, and thru the encouragement of the owner of the Stretch, I've really stopped 'being afraid' of any steel. Granted, no one wants to screw up their edge; some are more challenging. I did a heavy reprofile on my M4 Military and that was my biggest PITA so far, but I just look at each experience as an opportunity to hone my skills. It came out wonderfully. I've since picked up a Dragonfly in ZDP and got satisfactory results touching it up on my Sharpmaker.

Don't give up! Just keep at it and listen to what the steel says to you as you work. If I can do it, anyone can!

 

[FK]

I use DMT plates to remove the factory edge,, that took some time.
It was not very even and had deep grinding marks, est. 240 belt.
Checked the edge with 10x loop frequently.
Next was hard leather with diamond paste to mirror polish.

Have Delica, Endura and Stretch in ZDP-189.

Regards,
FK

 

[carbonsteelfan]

Dean...awesome post, Brother! Cool to see proof of what so man of us have wondered about and others 'knew'. I had no idea what a Rockwell Hardness test looked like, so double bonus for me!



Carbon, I held off for a long time before purchasing something in ZDP out of fear this happening to me. Sheepishly, I picked up an Endura. But, I haven't found it nearly as hard to sharpen as I had worried. I'm an EP user and my first experience with ZDP was on my buddy's Stretch. It didn't come out as well as I had hoped, but it was more a result of my lack of EP experience at the time than the steel. Since then, and thru the encouragement of the owner of the Stretch, I've really stopped 'being afraid' of any steel. Granted, no one wants to screw up their edge; some are more challenging. I did a heavy reprofile on my M4 Military and that was my biggest PITA so far, but I just look at each experience as an opportunity to hone my skills. It came out wonderfully. I've since picked up a Dragonfly in ZDP and got satisfactory results touching it up on my Sharpmaker.

Don't give up! Just keep at it and listen to what the steel says to you as you work. If I can do it, anyone can!

Thanks man I finally got the damn thing sharp using a Lansky

 

[gunmike1]

My Endura ZDP 189 model is 63 RC, and my ZDP/CFStretch is 65 RC. They sharpen up relatively easy with diamonds or Shapton Glasstones, at least compared to the higher Vanadium steels. They certainly are easier to sharpen on the glasstones than S90V. But compared to VG-10, ZDP-189 certainly does take a good bit more time to reprofile.

 

[JD Spydo]

I've been a fan of ZDP-189 blade steel since Spyderco's very first folder in that steel was released in 2005>> and that was the Burgundy Caly jr. model which I still have by the way. Everything you say about ZDP-189 I will agree with>> but there is one weekness or you might say that the "Achilles' Heel" of that blade steel deals with food uses.

About 7 years ago when I still had my extensive tomato garden I was growing ( 22 varieties) I took some sample fruit from my "Cherokee Purple" variety of tomato and sliced up a few of them with my Burgundy Caly Jr.. I failed to rinse off the tomato juice from the blade and the very next day it was as though termites had eaten into it I had never seen corrosion of that level done that fast on a stainless blade ever in my life. It was so bad that I even sent the blade back to Spyderco "Warranty & Repair" department after talking to them on the phone about it

They did a really good job of re-sharpening it and polishing it. But I'm here to warn all of you that ZDP-189 is very vulnerable to food acids

If you do any type of food processing with your ZDP-189 blades I'm telling you that you better rinse and wash it immediately when you're finished with it>> better yet do your food work with a steel that much more corrosion resistant like AUS-8, VG-10 or even H-1 for that matter>> because ZDP-189 doesn't resist food acids at all IMO.

 

[nccole]

I've been a fan of ZDP-189 blade steel since Spyderco's very first folder in that steel was released in 2005>> and that was the Burgundy Caly jr. model which I still have by the way. Everything you say about ZDP-189 I will agree with>> but there is one weekness or you might say that the "Achilles' Heel" of that blade steel deals with food uses.

About 7 years ago when I still had my extensive tomato garden I was growing ( 22 varieties) I took some sample fruit from my "Cherokee Purple" variety of tomato and sliced up a few of them with my Burgundy Caly Jr.. I failed to rinse off the tomato juice from the blade and the very next day it was as though termites had eaten into it I had never seen corrosion of that level done that fast on a stainless blade ever in my life. It was so bad that I even sent the blade back to Spyderco "Warranty & Repair" department after talking to them on the phone about it

They did a really good job of re-sharpening it and polishing it. But I'm here to warn all of you that ZDP-189 is very vulnerable to food acids

If you do any type of food processing with your ZDP-189 blades I'm telling you that you better rinse and wash it immediately when you're finished with it>> better yet do your food work with a steel that much more corrosion resistant like AUS-8, VG-10 or even H-1 for that matter>> because ZDP-189 doesn't resist food acids at all IMO.

I'm no expert, but here is my understanding. The thing with ZDP-189 is it's Cr, which is what gives it is stain resistance, is used in the formation of carbides in a way somewhat unique to that steel. The harder you run it, the more Cr gets used in carbide formation and the less is left to resist corrosion. My guess is that little Caly Jr. was run harder. My full ZDP-189 CF Stretch has shown to rust much easier than my laminated Caly 3 CF. Unfortunately, I've never used either one of those hard enough to tell a difference.

To the OP, not to nitpick but is that tester calibrated? Looks pretty old, just curious.

 

[SpeedHoles]

I've been a fan of ZDP-189 blade steel since Spyderco's very first folder in that steel was released in 2005>> and that was the Burgundy Caly jr. model which I still have by the way. Everything you say about ZDP-189 I will agree with>> but there is one weekness or you might say that the "Achilles' Heel" of that blade steel deals with food uses.

About 7 years ago when I still had my extensive tomato garden I was growing ( 22 varieties) I took some sample fruit from my "Cherokee Purple" variety of tomato and sliced up a few of them with my Burgundy Caly Jr.. I failed to rinse off the tomato juice from the blade and the very next day it was as though termites had eaten into it I had never seen corrosion of that level done that fast on a stainless blade ever in my life. It was so bad that I even sent the blade back to Spyderco "Warranty & Repair" department after talking to them on the phone about it

They did a really good job of re-sharpening it and polishing it. But I'm here to warn all of you that ZDP-189 is very vulnerable to food acids

If you do any type of food processing with your ZDP-189 blades I'm telling you that you better rinse and wash it immediately when you're finished with it>> better yet do your food work with a steel that much more corrosion resistant like AUS-8, VG-10 or even H-1 for that matter>> because ZDP-189 doesn't resist food acids at all IMO.

I believe your experience was atypical.

I have owned over half a dozen different models in ZDP-189. Still own and use most of them.
I often use them with food prep, mostly including fruits, and plenty of tomatoes... I have left mine over night without washing on purpose just to test. Not one bit of corrosion, let alone any sort of deep pitting.
Maybe you needed to use yours more and get a light patina of sorts onto the steel. Mine have just clouded over in a slightly grey haze.

I have also soaked it in vinegar and left it overnight without cleaning.

Also stir my coffee with them... cut sandwiches with pickles and mustard... etc, etc.
ZDP-189 technically might just barely be into the stainless classification, but it's shown plenty of resistance for me to not worry.
There have been reviews also showing these blades to be more stainless than the liners when used in salt water! :thumbup:

 

[JD Spydo]

I believe your experience was atypical.

I have owned over half a dozen different models in ZDP-189. Still own and use most of them.
I often use them with food prep, mostly including fruits, and plenty of tomatoes... I have left mine over night without washing on purpose just to test. Not one bit of corrosion, let alone any sort of deep pitting.
Maybe you needed to use yours more and get a light patina of sorts onto the steel. Mine have just clouded over in a slightly grey haze.

I have also soaked it in vinegar and left it overnight without cleaning.
Also stir my coffee with them... cut sandwiches with pickles and mustard... etc, etc.
ZDP-189 technically might just barely be into the stainless classification, but it's shown plenty of resistance for me to not worry.
There have been reviews also showing these blades to be more stainless than the liners when used in salt water! :thumbup:

Maybe you've hit on something there concerning a "PATINA" And maybe that was my own undoing Because I tend to give all my stainless blades the ultimate "FLITZ" treatment>> I either use FLITZ polish or in some cases I use Flitz's metal wax. I've never really looked into allowing a knife blade to accrue a "patina". Because if you would have seen that ZDP-189 blade of mine after I left it in a bath of tomato acid you would have probably either screamed or blew a panel of high amperage fuses

But Brother you've certainly got my attention on that one>> and I will check into it. Spyderco themselves acted as though they were clueless when I talked to them they said it was a first time for them. And I've never had anything like it happen with any of my other Spyderco knives ( or any other premium knife for that matter). And I've had quite a selection of blade steels over the years too.

I have been told that those "Cherokee Purple" tomatoes I was growing did have a high acid content. But looking back on it and after what you've said I'm now sure that there were probably other contributing factors. But I'm sure going to protect my blades better in the future I can assure you

 

[SaintZe]

I too have had variable experience with ZDP. My dragonfly II rusted and pitted after about an hour of cutting tomatoes and tomato plants, to the point that I had to put a new edge on it to repair the damage. My Caly 3, on the other hand, survived several hours immersed in vinegar with nothing more than a night imperceptible change in hue.

 

[SpeedHoles]

I do believe there is such a thing as making a blade "too clean". This may have been part of it??
If someone were to clean their blade with isopropyl alcohol, then leave it dry, I feel like it may be more susceptible to corrosion.


And closely related to what nccole was saying, it seems to be quite possible that some batches, depending on how they were treated, may have more or less carbides exposed (this is not something I know much about) resulting in more pitting on some, and very stainless on others.

 

[jpm2]

Interesting thread, hard to say what the real differences are between opposing experiences.

I have a zdp delica that has been used for everything, with little to no staining, much less pitting.

One curious observation I made was that a vg10 delica showed mild staining (specks) after a couple hours of work in a mild H2S, yet very humid environment. The zdp delica showed nothing detectible doing the same work, same amount of time, in the same environment.

The curious part to me being, vg10 is popularly considered more corrosion resistant than zdp.

 

[fshaw]

I'm sure to be the odd man out here but I have a CF Stretch on the table beside me as I type this. I find it extremely unimpressive in edge retention. One of the bigger disappointments I've had in higher end production knives. I was really hoping for something exceptional and the ZPD in my Stretch isn't it for me. Glad you guys have had better experiences. Mine seems pretty ordinary.

 

[SpeedHoles]

I'm sure to be the odd man out here but I have a CF Stretch on the table beside me as I type this. I find it extremely unimpressive in edge retention. One of the bigger disappointments I've had in higher end production knives. I was really hoping for something exceptional and the ZPD in my Stretch isn't it for me. Glad you guys have had better experiences. Mine seems pretty ordinary.

Not that I'm out to convince you otherwise, but may come down to your sharpening process or edge finish??