tarnishing 5160

[claude]

I have made some kitchen knives out of 5160 and have been using them. The trouble is that they tarnish and discolor very quickly, is that normal or should I have put some kind of protective coating on them or finished them differently (satin finish). I asked the wife if she had let them soak in water and she said no and she hasn't put them in the dishwasher either. Thanks in advance
Claude

 

[etp777]

I'm sure someone will chime in who has more experience with 5160, but with my HI khukuris, I try to keep a coating of oil on them, and they seem fine so far, even with the heat and humidity here in OK. I wipe them down with three in one oil, or remoil, or whatever I have around after I use and clean them.

As these are cooking knives, I would suggest food grade mineral oil.

Oh yeah, and a mirror polish will tend to be a bit more corrosion resistant than satin/brushed/hand rubbed/etc. Mirror polish seems to leave less microvoids which trap the water and help corrosion.

That being said, if you clean them well, dry them well, then oil them after each use, the microvoids also hold oil better. SO it's kind of a tradeoff. I think if you coat them with mineral oil after use you'd probalby be fine.

last comment, is that at least with my hunting knives(all high carbon), I like the patina they start to get. I tend to use them in kitchen too, at least when I'm preparing stuff for dehydrator, as my Buch and Schrade hunting knives just seem more useful at times than my kitchen knives(esp. when cutting up steaks for jerky). But with the fruit juices, and blood and stuff the schrade has a nie patin. polished it off once or twice, then realized that it showed exactly what it was, a high carbon knife that actually got used, rather than sitting on a shelf. After that, didn't really mind.

 

[Mike Hull]

Yes, in food service 5160 will tarnish rather quickly.
There's not much you can do to prevent this.

Nothing wrong with the discoloration, unless it really bothers you. Just keep them sharp, make sure there is no live rust starting on them, and wipe them with food grade mineral oil for some protection. You can get that at any pharmacy.

 

[Dan Gray]

I think the patina gives it character
the acids in food will do that, meat will the most
you don't see good ole knives like that much any more in most the kitchens.
did you know that stainless knives with turn some
veggies brown and the high carbon knives won't.

 

[mete]

When finished clean immediately with hot soapy water , dry immediately. Forget the oil and get used to the patina it's a working knife not a show piece.

 

[Jason Cutter]

Good ole carbon steel. I always tell people that the patina / tarnish is a visual reminder that you have in your possession a SUPERIOR CUTTING TOOL !!! I'm stepping in it again, but I stand by my faith in carbon tool steels.

As mentioned, I second that you don't need to oil your knives unless maybe for long-term storage. Clean, and dry is the key. Some professional knife users use their carbon steel knives all day and only ever clean up after a good 8hours work. Their knives look no different from one thats been meticulously cleaned every 10minutes.

Remember that like many controlled oxidation finishes (blueing, phosphatising, French Graying)the tarnish actually sets up automatically as a temporary barrier against further oxidation, so it is actually self-limiting to a certain degree (eg.- during use).

If it really bothers you, the metal polishes can be used but you end up taking off a bit of metal each time and remember to clean the stuff off well. Doesn't digest really well.

Just a few thoughts. Jason.

 

[RHINOKNIVES]

bees wax works much better than oil. if it really bugs you try some bee/parafin wax. a little greying won't hurt anything. do you remember grannys knives? they looked like that.