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How to deal with reactive knife?

Mon Sep 02, 2013 8:21 am

To whom it may concern,

I have a Moritaka 240mm AS Gyuto that I recently purchased and have been having a lot of trouble with it. First off, I want to say it is an amazing knife, which is why I want to make it work so bad.
Within in a few days of using the knife for work, the kurouchi finish started coming off. As of now, it is all but completely gone. Ascetically I'm at a loss, but thats ok, I can live with out it. What really kills me is that the metal that was underneath the kurouchi finish is extremely reactive and rusts continually throughout the day, and I do make sure to keep the knife dry.

I'm asking for some advice and what my options are. Is this common with these knives? What are some things I can do to keep the knife from being so reactive? I have tried to force a patina on the metal that was under the kurouchi finish but to no avail. Any ideas or options would be appreciated.

Thank you for taking the time to read this and I am looking forward to hearing back from you. Thank you.


Re: How to deal with reactive knife?

Mon Sep 02, 2013 8:28 am

Hi Jordan,

This is somewhat typical. I can help. You want to force a patina on the blade and once it's developed you want to keep it on. Patina will form a protective barrier between the steel and the environment you are using it in. It won't eliminate rust but it will slow it down a lot.

To force a patina just clean the knife, dry it and then slather it with mustard. Most anything will work that has a descent amount of acid in it but mustard is cheap and easy to come by and has lots of vinegar in it. Let it sit for about 30 minutes and then clean it off. That should get you started. Then, when you use the knife don't scrub it, wash it with a sponge and soapy water so you don't remove the patina. As you use the knife you should notice it will be far less reactive.

Tell us how it goes.

Re: How to deal with reactive knife?

Mon Sep 02, 2013 8:30 am

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