found rust/pitting while sharpening carbon gyuto

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spoiledbroth

spoiledbroth

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I was sharpening up my carbon knife today, and did a bit of a **** on the shoulder of the blade... Didn't notice really until I cleaned away the mud from my polishing stone that there were some little black specks on the shoulder rash... I broke out my 15x lighted loupe and it looks like it's some little red pits (even at 15x I have trouble making them out, and my eyes are fine).

Is this a bad sign? Deep pitting? I had scrubbed the knife clean earlier in the week and had not noticed anything like this on the surface... I know this isn't much help without pics but I've not got a camera.

Is it safe to just grind the rust out with a lower grit stone?
 
If what you have is rust you can remove it more gently with some kind of crome polish. Many from the US mention 'Barkeepers friend'. I suppose it is a brand in polishing compounds. I use 'Autosol' wich is a polishing paste that reminds me of tooth paste. It says 'Chrome polish'.
You want to use this paste with a cloth or some newspaper. The blade will become shiny and the rust development stops.
Hope this was helpfyll even though it might not remove all signs of the pitting (if it is deep).
- Kim
 
KimBronnum said:
If what you have is rust you can remove it more gently with some kind of crome polish. Many from the US mention 'Barkeepers friend'. I suppose it is a brand in polishing compounds. I use 'Autosol' wich is a polishing paste that reminds me of tooth paste. It says 'Chrome polish'.
You want to use this paste with a cloth or some newspaper. The blade will become shiny and the rust development stops.
Hope this was helpfyll even though it might not remove all signs of the pitting (if it is deep).
- Kim
Click to expand...
Hmm. Am I to understand that the only way to be sure that the rust has halted in its' tracks is to use a product like BKF or Autosol (both are available to me locally for cheap)-- will Baking Soda work too?

Thanks for your time.

Also is it important to dry your knife off constantly while sharpening? Could the rust have developed from that? I usually wouldnt wipe down any knife I'm sharpening until I'm ready to test out the edge (so the few MM before the edge would be wet for as much as 10-15 mins at a time)...
 
I've found that these work very well too. I thought I'd oiled up a carbon knife well enough before storing it away for a couple weeks. Nope. Had a couple rust spots and had to bust out these babies. Did the trick, only used the "fine" one because it wasn't too bad.

http://www.amazon.com/dp/B00FS0BFJC/?tag=skimlinks_replacement-20
 
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FWIW I had been playing with forced patinas the last few weeks (no rust to speak of there...) and then cut up about 5 or 6 loins of albacore, which removed the ****** grey patina and left a pretty cool iridescent blue one. But yeah the knife wast patinated already, the tiny rust spots (smaller than the width of a human hair) are all on the right side of the bevel, which for this knife is quite steep. Patina starting to build up on the edges but I would prefer not to force patina here as I'm just going to take the edge off the knife.

Also I agree with ChinaCats I am not a fan of forced patinas the natural ones come out waaaaaaay cooler (iridescent) and less ODC looking. Next paycheque I plan to get the medium and fine sabitori and am thinking about cleaning the knife off so I can get something neater going.

Do natural patinas eventually go that dull grey colour?

Also thanks for all the replies! I am kind of scared to screw up my first monosteel carbon knife, but I think I can chill out a little, looking through the Patina thread I thought there is relatively little cause for concern I think my knife is in pretty decent shape. Hope to get a camera for KKF soon... :/
 
Patina is a further oxidation of common rust. Before a patina gets installed some light, superficial rust is unavoidable and necessary. To help transformation into a patina you rinse with really hot water.
 
How did you remove the grey patina to get the blue? I've never forced one before.
 
Not so sure any blue patina will stay that way. Eventually all will turn more or less black with different shades though. Numerous variables: steel, finish, food...
 
sharptools said:
How did you remove the grey patina to get the blue? I've never forced one before.
Click to expand...

just cutting tuna, I wasn't being tremendously careful wiping the knife off; when I finally cleaned it off I noticed the old patina had a kind of blue buildup on top of it.
 
spoiledbroth said:
I am kind of scared to screw up my first monosteel carbon knife, but I think I can chill out a little, looking through the Patina thread I thought there is relatively little cause for concern I think my knife is in pretty decent shape. Hope to get a camera for KKF soon... :/
Click to expand...

Went through the same anxieties with my 1st monosteel carbon, but it ended up being no problem. A tiny bit of reactivity with onions, chillis, garlic, citrus, etc for the first couple of weeks and now it is settled in very nicely, no issues. Really cool natural patinas that shift and change as you continue to use the knife. Have fun :)
 
My Misono Swedish steel knives don't even give off the sulphur smell that much anymore. I remember I forced a patio on mine using Hellmann's mayonnaise (thick coating for 3+ hours, twice) and it looked as if rust was coming up to the surface, but once wiped off and washed it had the greyish colors. I think the blotchy-ness is due to the separation of the emulsified oil/water/acid or air pockets.

A before/after picture on my santoku is here:
http://www.kitchenknifeforums.com/showthread.php/7655-Show-your-newest-knife-buy?p=344610#post344610
 
Another question, I read in another thread that the Japanese chefs regard patina as a bad thing and scrub with baking soda regularly. How do they deal with reactivity? Do they just ignore it? or soak everything cut in water? Anyone know?
 
The baking soda is scrubbed onto the knife daily before work. No, do not soak your ingredients in water. Just keep a wet hand towel folded in one corner of your workspace, and a dry one in the other. Every few cuts on something acidic it's a great idea to wipe down the blade with the wet rag to reduce the acidity on the faces/cutting edge--- dry the blade off and keep cutting. The knife could then be scrubbed down with an eraser (rust eraser, sabitoru/sabitori) or something abrasive to remove any patina formation at the end of the day.
 
sharptools said:
Another question, I read in another thread that the Japanese chefs regard patina as a bad thing and scrub with baking soda regularly. How do they deal with reactivity? Do they just ignore it? or soak everything cut in water? Anyone know?
Click to expand...

Here's a good video on how to work with carbon steel knives in order to keep them clean while you cook:

http://m.youtube.com/watch?v=tza5pymb5yg
 
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