zdp-189 forced patina experiment

[simioh]

I bought a used Endura in zdp-189 and it came with some light rust and patina. So I remembered reading you could force a patina with mustard, vinegar and other acidic foods, so I decided to give it a try.

First I wrapped a textured paper towel (like Bounty) around the blade and soaked it in rice vinegar. after about 5 minutes I took the paper off and cleaned the blade. To my surprise, the blade now had an imprint of the paper towel's texture. It looked pretty cool, but still looked dirty.

Next, I decided to try a pattern. I applied some mustard and some habanero hot sauce to the blade.


After 30 minutes these were the results:

Finally, I decided to try to even it all out by wrapping the blade in a paper towel and soaking it in vinegar again. I'm going to let it sit like this for about an hour and then unwrap it.

(notice the "Spyder-bite" on my thumb, courtesy of my Pacific Salt)

Stay tuned for the results...

 

[brets-ftw]

Looking pretty good, a little surprised that it took as ZDP has so much Chromium.

 

[JuJu-]

cool experiment!

 

[simioh]

Final results are in:

Not bad, I wish both sides would've come out more like the second picture.

What do you think?

 

[chrisfa]

Now its yours and totally unique to you

 

[whetrock]

I too am somewhat surprised at the results. I love the way a nice grayish or dark black patina looks on a blade. I've been using a ZDP-189 Stretch for quite some time now and it shows no signs of patina. I may be tempted to force one after seeing this thread. I've found that with my carbon steel knives that totally submerging the blades in a cup of vinegar overnight is the best bet at a darker than dark black patina. I can't help but wonder how ZDP-189 would respond to such a treatment.

 

[jimnolimit]

I can't help but wonder how ZDP-189 would respond to such a treatment.

even though ZDP has 20% chromium, it also has 3% carbon. what happens is that a lot of the chromium gets locked up into chromium carbide, which means it can't help with corrosion resistance.

it's not just the amount of chromium in a steel that makes it stainless, it's also the ratio of carbon to chromium that effects corrosion resistance (some other factors will also have an influence).

 

[simioh]

...I've found that with my carbon steel knives that totally submerging the blades in a cup of vinegar overnight is the best bet at a darker than dark black patina. I can't help but wonder how ZDP-189 would respond to such a treatment.

I thought about doing that, but didn't have enough vinegar.

 

[Ankerson]

Looking pretty good, a little surprised that it took as ZDP has so much Chromium.

Most of it goes into carbide formation due to the HT and tempering process to get it into that 64-65+ range.

 

[brets-ftw]

even though ZDP has 20% chromium, it also has 3% carbon. what happens is that a lot of the chromium gets locked up into chromium carbide, which means it can't help with corrosion resistance.

it's not just the amount of chromium in a steel that makes it stainless, it's also the ratio of carbon to chromium that effects corrosion resistance (some other factors will also have an influence).

Most of it goes into carbide formation due to the HT and tempering process to get it into that 64-65+ range.

Ah, Thanks for the clarification guys.

 

[viper89]

Pretty cool patina and very creative with the towel. great job.

 

[simioh]

Pretty cool patina and very creative with the towel. great job.

Thanks! More than creativity, it was dumb luck.

 

[sodak]

It's pretty amazing how much carbon is in ZDP 189. 30 years ago, it would have been called something else - cast iron. Gotta love technology.

 

[Melektau]

:thumbup:Just what I was looking for thanks much friend

 

[spoonrobot]

A four hour soak in apple cider vinegar pretty much destroyed the edge of my ZDP189 Stretch.

From the bottom of Post #7:
http://www.bladeforums.com/forums/s...189-FRN-Stretch-(warning-very-picture-heavy!)

However, after dunking the SFRN (Stretch FRN) blade in apple cider vinegar for 4 hours to remove the staining (which it did quite nicely) I resharpened the blade on my Sharpmaker and then cut up some cardboard.

After only a few cuts I noticed that the edge was chipping extremely badly, worse than anything I've ever seen. This appears to have been caused by corrosion during the ACV bath.

 

[SpeedHoles]

Interesting results...
I am considering forcing a light light patina onto a used knife I just picked up with ZDP-189

Might have to give it some splashes of rice vinegar.
No soaking for hours for me though, haha