Z-Cut blade discoloration

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cgjones
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Z-Cut blade discoloration

#1

Post by cgjones »

Has anyone else run into a similar issue with the Z-Cut? I was cutting the kernels off 6 ears of corn. The corn had been off the boil for at least a few minutes and I was using tongs to hold it. I'm not sure if this could have affected the heat treat or if I just heat anodized the blade.

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Re: Z-Cut blade discoloration

#2

Post by SubMicron »

What happens when you wipe it with mineral oil or alchohol?
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Re: Z-Cut blade discoloration

#3

Post by cgjones »

SubMicron wrote:
Mon Sep 14, 2020 10:51 am
What happens when you wipe it with mineral oil or alchohol?

I'll give it a try. The only thing I did was hand wash it with regular dish detergent.
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Re: Z-Cut blade discoloration

#4

Post by cgjones »

SubMicron wrote:
Mon Sep 14, 2020 10:51 am
What happens when you wipe it with mineral oil or alchohol?

I tried both and neither had any effect.
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Re: Z-Cut blade discoloration

#5

Post by TkoK83Spy »

May be a permanent patina. Looks pretty awesome in my opinion!!

But, if you want to try and get rid of it, give Flitz a try.
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Re: Z-Cut blade discoloration

#6

Post by SubMicron »

TkoK83Spy wrote:
Mon Sep 14, 2020 12:23 pm
May be a permanent patina. Looks pretty awesome in my opinion!!
I actually ordered one right after I saw the picture.

$20 for BD1N in a functional kitchen geometry? I'm in!

I chose the PE Pointy Tip
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Re: Z-Cut blade discoloration

#7

Post by Mike Blue »

First, you're right handed, or you were cutting corn right handed.
These are oxidation colors/patina but boiling water for corn should not be enough to cause steel to lose hardness. Increased heat may make this process more active than room temperature. Possibly something in the water as a chemical reactant.
People who know BD1N better will know more. There are reports of patination but not rusting in Google.
Flitz or similar should remove the colors easily.
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Re: Z-Cut blade discoloration

#8

Post by Doc Dan »

Well, it certainly looks like heat, perhaps oil heated on the blade gave it some surface color? I have 3 knives in this steel that really get worked out day in and day out each week and have had no discoloration.
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Re: Z-Cut blade discoloration

#9

Post by VashHash »

I agree it does look pretty cool. I haven't stained my BD1N kitchen knives yet. Cut limes with them and left them for awhile before washing with no ill effect. Hopefully it's just some sort of patina or stain.
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Re: Z-Cut blade discoloration

#10

Post by Cambertree »

SubMicron wrote:
Mon Sep 14, 2020 12:43 pm
TkoK83Spy wrote:
Mon Sep 14, 2020 12:23 pm
May be a permanent patina. Looks pretty awesome in my opinion!!
I actually ordered one right after I saw the picture.

$20 for BD1N in a functional kitchen geometry? I'm in!

I chose the PE Pointy Tip
Nice one. :)

It’s pretty cool to have a PE and SE version of the same Z-Cut side by side to play with on various materials in the kitchen.

It’s funny how one will cut much more effectively than the other, depending on what’s being cut.

I got the roundnosed versions. They’re awesome table knives too, a real hidden gem of a model for knife nerds everywhere. :D :p :)

I completely forgot to measure the factory BTE thickness on the PE model before I thinned it out, but they’re way thin bladestock.

The SE version ‘steers’ heavily when slicing thick, binding vegetables like cucumbers or carrots, because of the thin bladestock. On other materials like soft bread rolls and mushrooms it easily outperforms the PE.

Image

OP, I’ve never had that happen on my pair of Z-Cuts. Did you have residual oil on the blade or on the corn?

I believe the tempering range for CTS-BD1N is around 300-350 f, so the heat treat should be unaffected.
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Re: Z-Cut blade discoloration

#11

Post by bearfacedkiller »

I cannot explain the staining but that corn was nowhere near hot enough to mess up the temper of that knife.
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Re: Z-Cut blade discoloration

#12

Post by Doc Dan »

Yes and that made me think of oil. I’ve seen oil do that on polished metal when heat is applied.
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Re: Z-Cut blade discoloration

#13

Post by The Mastiff »

Salt in boiling water can do strange stuff including causing electrolysis from some pots. I'd just use Flitz or some other polish and be done with it. It wouldn't effect the temper and that is what matters. :)

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Re: Z-Cut blade discoloration

#14

Post by JRinFL »

https://youtu.be/OQSNhk5ICTI

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Re: Z-Cut blade discoloration

#15

Post by cgjones »

Thanks for all the ideas and suggestions! I think you guys are probably on the right track and it's just one or a combination of the various factors; heat, oil, salt, etc.

Mike Blue wrote:
Mon Sep 14, 2020 1:27 pm
First, you're right handed, or you were cutting corn right handed.
These are oxidation colors/patina but boiling water for corn should not be enough to cause steel to lose hardness. Increased heat may make this process more active than room temperature. Possibly something in the water as a chemical reactant.
People who know BD1N better will know more. There are reports of patination but not rusting in Google.
Flitz or similar should remove the colors easily.

I am indeed right handed.
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Re: Z-Cut blade discoloration

#16

Post by Mattysc42 »

All 3 of my z-cuts have patinad a bit like that. I like it.
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