I made my wife a kitchen knife for her birthday out of O-1 Steel, and I need a little help with care and maintenance.  I was actually pretty happy with how it turned out (see first picture).   I told her she'd have to clean it immediately after use and store it with a thin coat of mineral oil to ensure it doesn't rust.  Well, the first time she used it to cut some chicken, she said after about 7 minutes the blade had colored to what's shown in the second picture.   That staining will not come off with soap and water.   What is going on there?  I'm sure I could buff it or sand it back to clean, but is there something else we're doing wrong here?  Thanks in advance for your help!

 

 

Lodestone

That is wot carbon steel does. You did not say how fine a finish you did,,,the finer the better as rust,,,(the culprit) starts easier to not so fine finishes. Guns that have a blued finish,,or brown,,, are rusted in a way to obtain that color. and a rusted surface keeps its present condition longer. So,,The color you see will not likely change alot,,the care you described done every use will do well, Except,,,I believe mineral oil does not do well when ingested. See google if you wish..I would use vegetable oil, My mama wouild have wiped it with bacon fat. 

WOW!  It is a LOT prettier now!  Chickens eh?  I'll have to remember that trick!  Really a nice looking knife!  Stainless stays shiny (mostly)... but rarely holds the high quality edge of really good steel IME.  You have done well!

Let it ride man, carbon steel will get a patina in no time. I chopped up some potatoes and it left a very neat pattern on the blade. The only thing you could do to prevent that is to never use it really or you could slow it down by giving it a mirror finish and waxing the blade.

WOW!  It is a LOT prettier now!  Chickens eh?  I'll have to remember that trick!  Really a nice looking knife!  Stainless stays shiny (mostly)... but rarely holds the high quality edge of really good steel IME.  You have done well!

a knife grade  stainless steel will be fine if properly heat treated. If we use sub standard materials, we should expect to get poor results.

Don't forget, most store bought knives are made from knife grade stainless but they are far softer then almost any properly heat treated stainless knives made by hand.

440c got a bad reputation for being poor for that reason when in fact it's a really nice steel if heat treated properly.

I use nothing but carbon steel knives, they all are variations of dark grey and black. If needs be a green scots brite pad will remove any rust that may creep up if you forget and mistreat your knife. Like cast iron it takes a bit of care but some of my knives are over 50 years old.

I'd agree, some of my nicest knives are old carbon steel ones. They aren't "pretty" and shiny, but they have some of the nicest edges.

Ok, I feel a lot better now.  I thought I had overlooked something and maybe ruined the blade!   Thanks for your input fellas!

 

Lodestone

you may want to do a mustard/vinegar finish on your O 1 blade. O 1 tends to rust easily and takes the m/v finish readily. Simply mix mustard and vinegar and dab it on. the mustard is the medium and the acid in the vinegar etches the steel. let the mixture dry, wash it off, and start over again. 4-6 applications over a day or so seem to work for me. i like to sand the blade to 4-600 grit first to expose raw steel, then wash off the residue/grease with 409 or something comparable, and dry.  the areas with less thickness of the mixture will etch the most, so an even look can be obtained.

what's really interesting how smooth the blade becomes as the high spots from sanding are removed by the etching process.

john

(re- quote ''If we use sub standard materials, we should expect to get poor results'')

 

O1 is not sub standard knife steel Lodestone so don't let that comment bother you any, in fact many world renowned makers still to this day claim it to be 'one' of the best but ironically one of the cheapest steel stock to purchase, it remains one of my faves, edge retention and razor sharpness can be easily obtained and heat treating is among the easiest of steels........I prefer a stone wash forced patina myself but the variety of patina results and patterns are endless...........your knife looks great congrats on a fine job !!  

I agree with Gearheart and BCROB If you find a steel that works for you and it happens to be O1. Great. Some of us love to work with different stainless alloys. That's what works for them. Stainless is the way to go for daily wet areas ( meat cutting, and commercial or home kitchens for examples. I personally have very little experience in stainless.

(re- quote ''If we use sub standard materials, we should expect to get poor results'')

 

O1 is not sub standard knife steel Lodestone so don't let that comment bother you any,.....

I never said O-1 was not good, and I happen to like O-1, it is a fantastic steel for blades.  My quote was refering to the bad stainles some have used.    I even quoted bigfootnampa's statement about that in the reast of that post, I though that was clear