Tarnish or Patina and its Removal

[Miguelito's Blade]

I cut some strawberries with my Wat Pro Nakiri and the edge reacted to them. It is now darkened but, after searching for and reading relevant posts, I don't know if the discoloration is tarnish or patina, what the difference is between them, whether it is desirable or not, and, if not, what to use to remove it (I have some Flit on hand). I have learned so much from you guys that this is always the first and sometimes the only research I need to do. Thanks.

 

[HumbleHomeCook]

If it's from strawberries, I wouldn't stress it. Did the knife sit before being wiped off?

Orange is bad. Black can be bad. Dulling, bluing, etc. are just normal carbon reactions.

You could always post a pic.

 

[Miguelito's Blade]

It did not sit before wiping off. The color to me at least is dark bluish. My main concern is whether it--whatever it is--will dull the edge and therefore need to be removed. As to posting a pic, my mobility issues keep me from getting to the kitchen to take one but I will get one when my wife comes home for lunch.

 

[BillHanna]

I cut some strawberries yesterday with a CCK. My Mazaki petty did a lot of Strawberry Duty, as well. Almost instantly black, but still smooth to the touch. As someone who cuts lots of them for a 2 and 7 year old, its fine as long as it does not sit for long. Aesthetically, you may not like it, but it will not pit.

 

[Heckel7302]

Strawberries always turn my carbon steel knives very dark gray. Totally normal and nothing to worry about. If you want to remove it Flitz takes it off easily and won’t otherwise affect the finish.

 

[Cliff]

Acids will dull the edge, but that does not sound concerning. If you wipe the blade, with a clean, white cloth, does anything come off on the cloth?

 

[Miguelito's Blade]

Acids will dull the edge, but that does not sound concerning. If you wipe the blade, with a clean, white cloth, does anything come off on the cloth?

Nothing comes off. I have been furiously striving to become proficient to take any of my Japanese knives (all three of them) to the stones by the time they need it. If they need sharpening or a touch up it would be a toss up whether I would improve the edge or not. I would be comfortable with them on high grit stones such as an 8k.

 

[esoo]

You don't want your knife to look like this:

That type of orange has a flakiness to it that means bad rust. If you do see flaky orange, you want to address and clean it as soon as possible.

Aside from that most color you'll see on the core steel is fine.

 

[Miguelito's Blade]

You don't want your knife to look like this:

That type of orange has a flakiness to it that means bad rust. If you do see flaky orange, you want to address and clean it as soon as possible.

Aside from that most color you'll see on the core steel is fine.

Hopefully none of them will ever be as abused as that knife must have been. As long as the discoloration will neither pit nor dull the edge I have no problem with it.

 

[Delat]

Dark blue/grey from strawberries sounds pretty nice and easier than buying a steak. I might have to try that for putting a patina on my next knife.

 

[Miguelito's Blade]

Dark blue/grey from strawberries sounds pretty nice and easier than buying a steak. I might have to try that for putting a patina on my next knife.

I have begun to look at my problem from an entirely new perspective as not a problem at all. To confirm all that, I will be posting a pic within a couple of hours.

 

[Feiii]

Somebody far more experienced with patinas commented that their favourite way to force a patina is to use strawberries! Probably just a naturally strong reaction with those.

 

[esoo]

You may want to review these two threads to see what can happen to the carbon core of your knife:
https://www.kitchenknifeforums.com/threads/my-favorite-color-is-blue-a-patina-thread.299/https://www.kitchenknifeforums.com/...-is-used-the-unvarnished-patina-thread.42735/

 

[Miguelito's Blade]

Somebody far more experienced with patinas commented that their favourite way to force a patina is to use strawberries! Probably just a naturally strong reaction with those.

That's good to know. Thanks for posting it.

 

[Miguelito's Blade]

You may want to review these two threads to see what can happen to the carbon core of your knife:
https://www.kitchenknifeforums.com/threads/my-favorite-color-is-blue-a-patina-thread.299/https://www.kitchenknifeforums.com/...-is-used-the-unvarnished-patina-thread.42735/

Somehow I had not gotten around to reading those threads. Thanks for the link.

 

[bzalforno]

I have begun to look at my problem from an entirely new perspective as not a problem at all. To confirm all that, I will be posting a pic within a couple of hours.

 

[Miguelito's Blade]

It didn't happen. Maybe this evening. I would take the photo myself but I'm stuck in a hospital bed unless we go through a long procedure to put me in my chair.

 

[BoSharpens]

I'm sure someone has noted it, but I use crocus cloth which has fine iron oxide particles to clean up blade patina when it has stains or more severe rust (to a point.)

I have also resotred a lot of Sabatier knives from Europe in the last year that were well used and had some more pronounced rust. Crocus cloth doesn't deal effectively with thicker rust in any reasonable amount of time.

I don't see crocus cloth sold in hardware stores around me anymore. Don't know why. "Salesmen" have no idea when I ask as they just point to their fine grit aluminum oxide sheets as what I should use. Garbage recommendation.

 

[Miguelito's Blade]

Here are a couple of pics.

 

[HumbleHomeCook]

Here are a couple of pics.

All good.

 

[Greenbriel]

You don't want your knife to look like this:

That type of orange has a flakiness to it that means bad rust. If you do see flaky orange, you want to address and clean it as soon as possible.

Aside from that most color you'll see on the core steel is fine.

Yikes! Is that a Watoyama? How did that happen?

 

[esoo]

Yikes! Is that a Watoyama? How did that happen?

It's a cheap *ss Tojiro. I found the knife sitting like this near the end of the dinner prep my fiancee was doing. Took a minute with a rust eraser to remove that and bring it back to normal (as you can see here My favorite color is USED .......the unvarnished patina thread!)

After dealing with this on the cheap knives a few times, you definitely get less hung up.over patina and scratches