cut some food with my mora and the blade became black...help

Mad_Maxx

Mad_Maxx

Joined
Nov 29, 2007
Messages
2,519
hi guys!
got a few MORA knives today, a 780 triflex a 740 carbon and a mora 2000.
just finished dinner, istead of using a normal steak knife I used the 780 to see how it works, after eating i went to wash the fat and oil away.

After celaning within a few seconds a dark layer can be seen on the top half of the blade, seems some kind of corrosion, it stinks like rust.

what can I do? tried to clean it with alcohol and soap but afer a few seconds this layer comes back again.

any chance to get it back as shiny as before?
hope I did not riun a new knife...

thanks a lot

Maxx
 
All carbon steel knives are prone to this. The discoloration is called a patina, and is an oxide of iron, just like rust. Many knife enthusiasts like having a patina on their knives, as it not only tends to prevent rust and corrosion, but can look very attractive.

FYI there are certain foods you may not want to cut with a carbon steel blade, cabbage and banana for example. Cabbage itself can discolor and pick up a bad tasty, banana produces a funky dark gray discoloration that is both ugly, and doesn't make for a very durable patina.

If you do want to polish it off, you can use a metal polish like Flitz, or something like crocus cloth or ScotchBrite.
 
i looks like the one caused by the banana,
i found out talking with a friend that the lemon (citric acid) may have caused this
managed to remove the patina with a metal polish, polished 3x and now it seems as before

the knife is a laminated (carbon core, SS sides) mora and should not suffer rust or stain, now i know I have to pay attention :-)

YES it is a user but ruining it on the 1st day isn't the best

by the way i LOVe my new moras

thanks
Maxx
 
Patina is good on a carbon steel blade. It offers protection from rust and corrosion. well, it offers SOME protection. I would not worry about it, though. It's perfectly normal of a carbon blade.
 
Mad_Maxx said:
the knife is a laminated (carbon core, SS sides) mora and should not suffer rust or stain, now i know I have to pay attention :-)
Click to expand...

The other day I tried a stainless VG10 blade to use as an impromptu steak knife, and it also showed signs of dark discoloration. Looking back it must have been the citric acid in the marinade I used, but luckily it polished right off.
 
to echo what has been said...

forget about it, its good for you. its normal for carbon blades to take on the patina, and there is speculation that this patina will help to prevent further oxidation (read: rust)

you can polish it off with some steel wool or a scotchbrite pad, but its really unnecessary. if you let it sit, and develop that patina more, the stink will go away and everything will be fine. kitchen knives (and all other knives) for thousands of years have had patinas, and they have been fine.
 
Just the day before yersday I soaked my Mora 510 in a tall glass of apple vinegar. After an hour or two, I took it out and buffed it with a grey nylon pad. Then I soaked it again for an hour. Now, it's perfect. ((( :D )))
 
Mad_Maxx said:
YES it is a user but ruining it on the 1st day isn't the best
Click to expand...

A patina definitely won't ruin a knife. One of the first things I did with both my Mora 521 and my Spyderco Mule Team Knife (after playing with them for a bit) was to let them soak in a container of vinegar for a while to start to induce a patina. They're both knives that I'm going to use regularly anyway so they were bound to start developing patinas before long. I just helped them along a little bit.
 
StretchNM said:
Just the day before yersday I soaked my Mora 510 in a tall glass of apple vinegar. After an hour or two, I took it out and buffed it with a grey nylon pad. Then I soaked it again for an hour. Now, it's perfect. ((( :D )))
Click to expand...

If you don't include pictures, then you're just teasing us! :D I like a nice patina also.
 
which food were you cutting?
was it the cheese? that would explain a lot.
 
Shiny?! :barf:

Nice dark patina?!:thumbup::thumbup:

A patina is natural, and beautiful:
2316718525_2a88a5ba9c.jpg
 
sodak said:
If you don't include pictures, then you're just teasing us! :D I like a nice patina also.
Click to expand...

You're right! And I, for one, say Nay! to teasing..... :D

As you can see, my patina is not quite as dark as some might like. The grind was sharpened after forming the patina. A stainless Mora and a Bark River mini-Northstar for comparison:

Mora-Patina-02.jpg

Mora-Patina-03.jpg

Mora-Patina-04.jpg
 
Nice!!!!

I've got a great patina going on my CS Master Hunter, I'll try to get some pics of that as well. I used a lemon, and it made for a very blotchy one, dark in some areas, grey in others. I like it!
 
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