Question about ZDP189

[jdw]

I have been a fan of ZDP for years and I am wondering what recent steel that it most closely resembles? I read Larrin's article about it but it still left me slightly confused. Do some now consider it an inferior steeI? I am really not very good at sharpening but despite the general consensus of difficulty I find it relatively easy to sharpen as opposed to some other extremely high hardness steels and I kind of wonder why? Thanks to the board as always for any feedback.

[The Deacon]

I'll admit, I've never been a fan of ZDP-189. For one thing I found it far less rust resistant than VG-10. For another, I found that although it held an edge considerably longer it took considerably longer to sharpen, so a wash in that regard. Personally, I can't justify paying more for that set of characteristics. That said, just like the performance fanatics on car forums, and the stopping power fanatics on gun forums, a lot of folks here seem to always be looking for a steel that offers "more" of whatever they value most.

[JohnDoe99]

I am really not very good at sharpening but despite the general consensus of difficulty I find it relatively easy to sharpen as opposed to some other extremely high hardness steels and I kind of wonder why? Thanks to the board as always for any feedback.

Since S30V came out Vanadium and then Niobium became the big deal carbide formers, abandoning the traditional high chromium steels like 440c and D2 for wear resistance. It didn't take long for people to start noticing edge stability problems, S35VN, S45VN, and now the SPY steel are examples of this attempt to correct the vandadium issue; a constant retreat in vanadium carbide amount.

Japan's response was instead of playing with all these carbide forming metals we've never used before in knives, lets just massively increase the amount of chromium carbide in a steel. So with ZDP-189 you have s90v level of vanadium wear resistance, but you don't have the problems vanadium poses. Where you need diamond abrasives and special care when sharpening something that is really, really brittle and fickle like s110v, you can use "normal" abrasives like an india stone for example and ceramics and then strop off of bare leather and be good to go with ZDP-189. ZDP-189 still takes a long time to sharpen but the idea is that you have higher edge stability because you're working with a "softer" carbide former. With so much chromium though the steel is still brittle, and it will be less corrosion resistant because of the huge amount of carbon necessary to get the high chromium wear resistance, but again the goal was to equal s90v level vanadium steels but with better edge stability. ZDP-189 doesn't really resemble any other steel out there, think of it as VG-10 on steroids.

[JohnDoe99]

accidentally quoted my post

[Ankerson]

I am really not very good at sharpening but despite the general consensus of difficulty I find it relatively easy to sharpen as opposed to some other extremely high hardness steels and I kind of wonder why? Thanks to the board as always for any feedback.

Since S30V came out Vanadium and then Niobium became the big deal carbide formers, abandoning the traditional high chromium steels like 440c and D2 for wear resistance. It didn't take long for people to start noticing edge stability problems, S35VN, S45VN, and now the SPY steel are examples of this attempt to correct the vandadium issue; a constant retreat in vanadium carbide amount.

Japan's response was instead of playing with all these carbide forming metals we've never used before in knives, lets just massively increase the amount of chromium carbide in a steel. So with ZDP-189 you have s90v level of vanadium wear resistance, but you don't have the problems vanadium poses. Where you need diamond abrasives and special care when sharpening something that is really, really brittle and fickle like s110v, you can use "normal" abrasives like an india stone for example and ceramics and then strop off of bare leather and be good to go with ZDP-189. ZDP-189 still takes a long time to sharpen but the idea is that you have higher edge stability because you're working with a "softer" carbide former. With so much chromium though the steel is still brittle, and it will be less corrosion resistant because of the huge amount of carbon necessary to get the high chromium wear resistance, but again the goal was to equal s90v level vanadium steels but with better edge stability. ZDP-189 doesn't really resemble any other steel out there, think of it as VG-10 on steroids.

Interesting post......

[Ankerson]

I have been a fan of ZDP for years and I am wondering what recent steel that it most closely resembles? I read Larrin's article about it but it still left me slightly confused. Do some now consider it an inferior steeI? I am really not very good at sharpening but despite the general consensus of difficulty I find it relatively easy to sharpen as opposed to some other extremely high hardness steels and I kind of wonder why? Thanks to the board as always for any feedback.

ZDP is OK.

The reason why it's pretty easy to sharpen is due to the softer Chromium carbides as opposed to the harder carbides found in most of the other steels.

Not really a fan of the steel however, but there really isn't a lot wrong with it depending.

It's normally run at high hardness so depending on the HT it can be chippy.

It's not very stainless due to most of the Chromium carbides being used to improve edge retention rather than stainless properties.

[TomAiello]

I actually really like ZDP. I find that it's easier to get it "scary sharp" than K390 (the real competitor to it in the Seki line) but that K390 holds a working edge longer. I'm really looking forward to getting my hands on a K390 Dragonfly to compare them straight across. My hunch is that I'll like the ZDP better for the (small, precise) tasks I use the Dragonfly for, but we'll see. I'm a big fan of K390, so I might be biased in that direction.

[Cambertree]

I also like ZDP189 a lot and use it frequently in the Dragonfly.

I think the hardness that Spyderco runs the steel at has changed over time. The Mules were run quite hard and from memory there were a couple of instances of cracking in use - perhaps around the plungeline IIRC?

My Caly 3.5 which is laminated seems to be run harder than the Dragonfly.

I generally put the most time commitment into the initial sharpening, where I thin out the edge at a fairly acute angle, then apply a ‘microbevel’ with the Sharpmaker for durability. (It’s not technically a microbevel as it’s visible with the naked eye, but you know what I mean.) It’s actually very quick to resharpen most steels using this technique as the contact area is very small - only a mm or two of edge bevel at the apex.

Over time the Sharpmaker apex gets wider and thicker, and eventually the knife will go back on the benchstones for thinning out again. Depending on how much I use the knife, this might be necessary once or twice a year.

Using my ZDP189 Dragonfly every day for work, I might spend a couple of minutes on the SM restoring that high level sharpness every week or so. I’ll sometimes finish with a couple of passes per side on a firm 1μm CBN loaded smoothside leather strop.

If the knife is being used very frequently on abrasive materials, I might do this every couple of days.

By ‘high level sharpness’ I mean a level where I have to apply very little pressure to cut. Basically just touching the edge lightly to thick pallet wrapping will make it readily spring apart. Likewise it should just glide through heavy multiwalled cardboards made for holding heavy industrial steel parts. The cardboard also often has tiny steel fragments and grinding dust on it.

As mentioned, the chromium carbides in ZDP189 work well with most common abrasives.

I find ZDP189 holds high level sharpness very well.

I think one significant difference with Japanese bladesteels is there is an assumption that the user can either sharpen competently or will make a basic commitment to learning how to sharpen to get the best out of the tool.

It seems to be a very common attitude among non knife afis in some Western countries that ‘I want a knife I never have to sharpen’ - and the steel choices in premium knives often seem to reflect this mentality of prioritising high wear resistance over other desirable traits like edge quality, sharpening response, and edge stability.

Larrin’s article basically said that ZDP189 is ‘overrated’ in terms of being claimed to be stainless when it’s not really in that category. This is true, but I’ll make a couple of remarks regarding my experience with ZDP189 in that regard. The steel takes a very good polish relatively easily, and this helps with practical corrosion resistance. I’m not talking about leaving it doused in corrosive or saline fluid, but with basic care it has been fine over years of use for me.

Another thing is if you are used to using tool steels and give ZDP189 a similar level of care, it will be fine.

If you prioritise stainlessness or work in wet environments it’s probably not the best choice for you.

Jdw, although ZDP189 is commonly compared to S90V in terms of wear resistance, I don’t think there’s really another US or European steel that is that similar to it.

[tonijedi]

I just have one knife in ZDP-189, a saber ground Delica.
I've never had an issue with ZDP-189 corrosion resistance.
After reading so many posts here about its lesser resistence and Larrin's article I made a series of unscientific kitchen counter tests:
1 hour coated with a fine layer of mustard - no corrosion
5 hours coated with lemon juice - no corrosion
4 hours coated in salt sutured water including salt rocks directlyon the blade - brown spots around the salt rocks were forming.

The brown rust could be removed with the nail and finger.

After reading a lot of posts here in the forums I was quite surprised it took sea salt to start to corrode this steel.

Edited to add: tests were I found "no corrosion" mean I was able to shave with the edge after the test.

[Larrin]

I just have one knife in ZDP-189, a saber ground Delica.
I've never had an issue with ZDP-189 corrosion resistance.
After reading so many posts here about its lesser resistence and Larrin's article I made a series of unscientific kitchen counter tests:
1 hour coated with a fine layer of mustard - no corrosion
5 hours coated with lemon juice - no corrosion
4 hours coated in salt sutured water including salt rocks directlyon the blade - brown spots around the salt rocks were forming.

The brown rust could be removed with the nail and finger.

After reading a lot of posts here in the forums I was quite surprised it took sea salt to start to corrode this steel.

Edited to add: tests were I found "no corrosion" mean I was able to shave with the edge after the test.

Was the edit correction because you also wanted to emphasize that sharpness was fine, or because there was minor corrosion but you deemed if it was sharp the cosmetic corrosion didn’t matter?

[ABX2011]

My experience with ZDP is that it's very chippy. It would be amongst my last choices for a premium steel.

[SubMicron]

I like ZDP-189 a lot, enough to buy it in a 2nd Spyderco

[JD Spydo]

The only big negative I've had with ZDP-189 is it's extremely poor corrosion resistance. Especially when dealing with food acids. I cut up a bunch of tomatoes a few years back with my Burgunday ZDP Caly Jr. and like a dummy I forgot to wash it off. The next morning it was as though I had soaked it in some industrial strength acid or caustic chemical brew. It pitted the blade so bad that I had to send it back to Spyderco.

So do beware that you essentially have the same properties of corrosion resistance that you have with many carbon steels.

On a positive note I do like the scary sharp edge you can attain with it. I will probably keep the ones I have with ZDP. I doubt if I would ever get a fixed blade with ZDP. But for sure it does have it's problems with corrosion resistance.

[Evil D]

The only steel I've had burr harder than ZDP was 154CM. The thing with ZDP is if you leave any trace of a burr it's going to chip. If you get a nice clean apex on it it's a pretty enjoyable steel. I'd have to echo Paul on this one though, I'm not sure the pros that it offers are worth the cons to me anymore over VG10.

[Matt Deaner]

I think ZDPs strengths are edge stability at low angles and that it can be sharpened with “normal” (I.e. non-diamond/non-cbn) equipment. It is not tough. It is not stainless. But for a pocket-scalpel it is quite nice.

I very much like it in my caly 3 and caly 3.5 each sharpened at 10 dps. I am less enamored with it in my stretch 1 and stretch 2’s, since the edges are ground thicker and the strong designs of the stretch models seem like they call for a tougher steel. Have had some small chips on the stretch 2. Stretch 1 seems a little soft and I don’t really like living with the downsides of zdp if it isn’t at least hard.

[tonijedi]

I just have one knife in ZDP-189, a saber ground Delica.
I've never had an issue with ZDP-189 corrosion resistance.
After reading so many posts here about its lesser resistence and Larrin's article I made a series of unscientific kitchen counter tests:
1 hour coated with a fine layer of mustard - no corrosion
5 hours coated with lemon juice - no corrosion
4 hours coated in salt sutured water including salt rocks directlyon the blade - brown spots around the salt rocks were forming.

The brown rust could be removed with the nail and finger.

After reading a lot of posts here in the forums I was quite surprised it took sea salt to start to corrode this steel.

Edited to add: tests were I found "no corrosion" mean I was able to shave with the edge after the test.

Was the edit correction because you also wanted to emphasize that sharpness was fine, or because there was minor corrosion but you deemed if it was sharp the cosmetic corrosion didn’t matter?

The edit was to emphasize that there was no visible corrosion and the edge wasn't "affected".

Has anyone achieved a forced patina with this steel? What's the procedure?