Help zdp189 or k390

[S-3 ranch]

Hard decisions new K390 stretch 2 or the stretch 2 in zdp 189 , he good ,bad , ugly of both
Only got the cash for one right now, and don’t know squat about those steels

[nerdlock]

K390 all day

[vivi]

K390 Stretch - Will hold an edge a bit longer, also has a fatter more comfortable handle

ZDP Stretch - Will have better corrosion resistance and will be more impressive in terms of build quality

I'd go K390/FRN myself but you can't go wrong with either.

[The Meat man]

K390 is a medium-high carbide steel (18% carbide IIRC). Spyderco heat treats it to around 64-66 from what I've seen. Most if not all the carbides are formed from Vanadium, (the hardest carbides), so it holds an edge really long. It's not stainless though and will patina/rust if you don't keep it reasonably clean.

ZDP-189 is very high carbide, nearly 30%. This steel is also run hard, though maybe a tad lower than K390. Say 63-64 RC. All the carbides are formed from Chromium, which isn't quite as hard as Vanadium carbides but still pretty good. Since the carbides are not quite as hard as Vanadium, you will be able to sharpen ZDP-189 over a wider variety of sharpening stone types. ZDP-189 is kind of on the border of being "stainless" and not; it's better than K390 but not as good as say CPM S30V.

[Snacktime]

Zdp Stretch is the only option, the straight spline is a deal breaker.

[Zive]

To be clear, is this a G10 ZDP or FRN?

Unless you want the more substantial feel and arguably better fit and finish that comes with the G10 version I would go with K390. It should hold an edge slightly longer. On paper ZDP looks stainless, but I’ve had pitting corrosion issues with the DF2 I carried IWB, while so far I’ve only had patina development with K390. I think there’s just so much carbon in there that it’s bound to react with salt, or if you’re ranching, blood.

Hope that helps

[S-3 ranch]

To be clear, is this a G10 ZDP or FRN?

Unless you want the more substantial feel and arguably better fit and finish that comes with the G10 version I would go with K390. It should hold an edge slightly longer. On paper ZDP looks stainless, but I’ve had pitting corrosion issues with the DF2 I carried IWB, while so far I’ve only had patina development with K390. I think there’s just so much carbon in there that it’s bound to react with salt, or if you’re ranching, blood.

Hope that helps

Yeah elements, and other stuff ( blood, salt, fertilizer) make VG10 more logical, I am looking at the frn models k390 is something I want more

[spoonrobot]

ZDP does not do well to exposure to salts or acidics. I had significant edge fracture when exposed to strong vinegar, acidic fruit, common table salt, and water softener salt. It's not a problem if you can wash the blade right away but if you cut dry and the knife goes back in your pocket on a warmer day the humidity is enough to cause an issue.

[TomAiello]

ZDP is easier to sharpen, if that's a concern for you.

[kennethsime]

I'll say this: the ZDP Stretch was my first Spyderco, and I loved it. That said, I haven't bothered to replace it. I do have the K390 on pre-order.

I'd go K390, but both are fantastic. I think K390 might be a bit tougher, ZDP a bit more stain resistant. Both will hold a fantastic edge.

Which do you like the color of better? Do you prefer the straight spine, or the drop point? Frankly, those might be more important factors right now.

[Baron Mind]

ZDP-189 is a great steel, but k390 outperforms it in almost every way. Given a choice between the two, the only reasons to choose zdp is if you wish to be able to sharpen it on aluminum oxide based stones, or because you already have a bunch of k390 and want to try something new. Sorry if this has been said already but that's the answer. Zdp can be effectively sharpened with AlOx, k390 can not.

[Matus]

ZDP Version in FRN is still fairly easy to find - just for the case if that should be part of the decision making.

And since I have used neither of the steels, let me comment on them :p First of all - the edge retention is going to be very comparable - whether you look at the CATRA tests done by Larrin or carboard cutting from some folks on YT. At comparable hardness the k390 is most likely not going to be any tougher. Edge stability can be a different story - I am not sure the data are available. In total - I would not call the k390 a necessarily a clear winner.

EDIT: The sharpening argument by Baron Mind is probably the most relevant point one in the whole discussion