New Magnacut, stained after first use in kitchen

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Then you need to cut apples with a 15N20 knife, because every slice imparts a flavor to the apple. 🤣
 
Here is my most used kitchen knife. My email says I ordered it February 2022. It has been used to cut most everything and is rarely washed right away. I don’t notice any obvious staining apart from some water marks. Given who I am I get questions every week, if not everyday, about various knife and steel issues. I would say 9 times out of 10 it was not a steel issue but related to some type of processing. And when I say that I am not referring only to MagnaCut but other steels as well. I have seen steels with significantly worse corrosion resistance like AEB-L and 154 survive in harsher conditions without serious corrosion.

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Can we really call surface oxidation corrosion? Corrosion sounds like it implies actual degradation of the material. That's why I said leave the knife wet for a few days, and I doubt it will rust, by which I meant the type of oxidation that eats steel and degrades edges, rather than colors a few molecules thick layer of the surface.
 
David Mary said:
Can we really call surface oxidation corrosion? Corrosion sounds like it implies actual degradation of the material. That's why I said leave the knife wet for a few days, and I doubt it will rust, by which I meant the type of oxidation that eats steel and degrades edges, rather than colors a few molecules thick layer of the surface.
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Since it is an oxide that forms it would qualify under most definitions of corrosion. However, the black oxide is different than rust. The biggest problem with rust is that it flakes away and the corrosion continues. So the performance of the knife would not be affected but the customer would have to decide if the appearance has been negatively affected. However, corrosion protection of stainless steel also occurs due to oxide formation, in that case a chromium oxide. Titanium and aluminum form their own invisible surface oxides which suppress further corrosion. The formation of that oxide layer is not typically called “corrosion” though it fits the definition.
 
ferider said:
Interesting. On a side note, I have a "stainless" revolver, that started rusting quite a bit, even though I maintained it well. I sent it back to S&W that blasted and re-passivated it (where I learned the term - seems to be routine for guns). No problem since then. Don't know of any knife maker who does it though.
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most likely it had cross contamination from machining between their different models.
Often why they send out for passivation

Stainless will naturally passivate itself IF it is of clean material.
If it has bits on non stainless from shared tooling, then it isn't clean, and will(could) corrode.
 
Here is a very nice custom that Richard338 Richard338 made and gifted me. His orders were to use it hard, and I am enjoying it a lot.

I use it for everything, including riding on my belt when spear fishing in the Pacific, and prawn diving in a river. It also served kitchen duty, cutting wood for stakes, trimming back jungle trails, etc.

Last week it was on my belt for six days while staying in a place only accessible by boat or helicopter.

It does stain a bit. But the edge remains crispy and no rust.IMG_1222.jpegIMG_1223.jpeg
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MolokaiRider said:
Here is a very nice custom that Richard338 Richard338 made and gifted me. His orders were to use it hard, and I am enjoying it a lot.

I use it for everything, including riding on my belt when spear fishing in the Pacific, and prawn diving in a river. It also served kitchen duty, cutting wood for stakes, trimming back jungle trails, etc.

Last week it was on my belt for six days while staying in a place only accessible by boat or helicopter.

It does stain a bit. But the edge remains crispy and no rust.View attachment 2638389View attachment 2638390
View attachment 2638391View attachment 2638392View attachment 2638393View attachment 2638405
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I remember when you originally posted about that knife. I'm glad to see it's still serving you well in paradise.
 
Slightly OT...
If you're interested in stories about unconventional clandestine. operations set mainly in Hawaii (a portion takes place on the Na Pali coast), take a look at "The Spy Who Spoke Porpoise" by Philip Wylie.
Very original in all aspects of the storyline, no sex (sorry), super character development, porpoises, retired circus performer, cobras, Russian submarines, lava tubes, volcanoes, exotic vegetation (manchineel, ylang-ylang), much more. I've read it at least 6 time over a somewhat long lifetime.
Old book, 1969, available for reading on Archive.org, and sometimes hardcopy on ebay.
 
Larrin said:
That is the stinger description for Google, you missed the “Is it a success?” question that followed. Meaning the reader is invited to read the article and come to his own conclusions. Of course it does not say or imply that the corrosion resistance is better than any other steel. The corrosion resistance is better than many other knife steels as I showed with the testing in the article.
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Your post, like your article, doesn't mention staining. Testing for stain resistance on a stainless steel, not just corrosion resistance etc.

craytab said:
you haven't used anything that would remove a light patina. You need an abrasive, like a polish. The flitz suggsted above is what I use when I need a light abrasive.
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The problem isn't removing the stain once, it's getting stained after food prep / meals and having to deal with that every time I use it, which is every day...with chemicals. It's a problem I never had before with any steel.

oldmanwilly said:
As promised, proof and pudding (or however that saying goes).

KezcbXu.jpeg

light patina only showed up after cutting raw, red meat.
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And mine's a skinner....

It's not just raw meat though, it's also cooked. I bought a Magnacut skinner so I can easily prepare meat, wash, and eat, without transference of material or 'patina'. On that end, it failed. It's a reality I would have liked to known before purchasing.
 
knifeism said:
Your post, like your article, doesn't mention staining. Testing for stain resistance on a stainless steel, not just corrosion resistance etc.



The problem isn't removing the stain once, it's getting stained after food prep / meals and having to deal with that every time I use it, which is every day...with chemicals. It's a problem I never had before with any steel.



And mine's a skinner....

It's not just raw meat though, it's also cooked. I bought a Magnacut skinner so I can easily prepare meat, and eat meat, and easily wash without transferring material or 'patina'. On that end, it failed completely. It's a reality I would have liked to known before purchasing.
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Fair criticism, I suppose, however I think we've reached a point of divergence. Testing of the steel has revealed it is highly stainless, however in real world use several Magnacut knives have developed a stain/patina from contact with meat. At point, the real question is whether the knives that develop patina have "contaminated" Magnacut: as in, are the contaminants being discolored or is the steel being discolored? I tend to think the former is the answer.

I say this because i have other Magnacut blades that have not taken patina. Specifically, my Hogue Deka has been used to cut all of the aforementioned foodstuffs without being cleaned immediately, and has taken no patina. I presume this is because the Deka has a higher level of finish which removed any potential contamination.

Regardless, the more I use Magnacut, the more I like it. Its corrosion resistance is more than satisfactory to me, but I sympathize if your experience is different. I forget, which knife of yours is problematic? Was it a Viper?
 
knifeism said:
Your post, like your article, doesn't mention staining. Testing for stain resistance on a stainless steel, not just corrosion resistance etc.
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As I already explained, staining is a form of corrosion. That’s why corrosion-resistant steel is called “stainless.” In my corrosion testing I did not observe staining hence why it was not mentioned in the article. Corrosion tests by other people have been reported online where staining was not found with various knives so it is not only me.
 
oldmanwilly said:
the real question is whether the knives that develop patina have "contaminated" Magnacut: as in, are the contaminants being discolored or is the steel being discolored? I tend to think the former is the answer.
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Maybe, I'd prefer it not being a question that all. I'm not one to 'baby' my knives, I want them to stay sharp and stain-free as long as possible, that's why I paid a few hundred for a low maintenance 'super-stainless' blade.

oldmanwilly said:
which knife of yours is problematic? Was it a Viper?
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Yep, best looking skinner there is. I just bought a Buck Alpha Hunter (in S35VN) which is similar in appearance, but hopefully not in lacking stain resistance. If that fails too, the next skinner on my list is a Helle for the polishing, but the only blade I like is Mandra and it's kinda small.
 
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Larrin said:
In my corrosion testing I did not observe staining hence why it was not mentioned in the article.
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But you only used salt-water to test for rust resistance. You didn't use meat, blood, etc to test for stain resistance. There are those here (and elsewhere) who did, and have shown Magnacut can have an extremely low resistance to staining.
 
knifeism said:
But you only used salt-water to test for rust resistance. You didn't use meat, blood, etc to test for stain resistance. There are those here (and elsewhere) who did, and have shown Magnacut can have an extremely low resistance to staining.
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I have no dog in this fight, but I do really like the MagnaCut knives I have. Mine have not shown any signs of corrosion and the reason I wanted MagnaCut was specifically for some of the conditions I am in. It also keeps an edge a long time and takes very little effort stropping it back to hair popping sharp.

I also know that just because it is the same steel, does not mean that all of the knives will be made the same or perform the same. Not all are ground ‘cleanly’, and not all are necessarily ground while taking into consideration the effect of overheating can have on the properties. I am not trying to badmouth your knife, or any makers- only stating that they may not all have the ideal properties ( just as knives from any steel may not have equal performance).

I am also not diminishing your concern- we all have different expectations and priorities and standards.
 
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