"Seasoning" carbon steel cooking knives

[elementfe]

As much as I patiently explain to my customers that carbon steel knives change color over time, now and then there's one who doesn't seem to get it.

Have any of you just gone ahead and put a grey patina on them so that what you see is what you get? What would be a good process?

I've played with mustard as a decorative treatment, but didn't really think that the resulting patina was very close to what happens over time with a well cared for HC knife.
Any thoughts?

 

[i4Marc]

Use the customer's knife in your own kitchen for a year then deliver to the customer. ;P

 

[elementfe]

As happy as I'd be to use any of the knives I make, it's likely that they'd get tired of waiting....oh! I could have them come cook at my place, then we'd all have a great time! Problem solved!

It was a serious question, though. I get a lot of people who have heard just how great HC knives are, but there's a learning curve that I'm trying to shorten a bit.

 

[james terrio]

I forced patinas on several carbon-steel bushcraft knives and they went over well. I haven't tried it with kitchen knives, though. I'll be interested to see what others have to say about your question

 

[elementfe]

It's one thing to get a knife just so, knowing that it may never be used to cut things- it's another to sell a product that's intended to be used several times a day, that's going to completely change its appearance.
Every time I think I'm in a trade where you just make it and sell it, it turns out that there's a major component that can't be ignored: Educating the customer!

Terrio, did you use mustard to force the patina?

 

[bronyblacksmith]

you could soak it in vinegar until it gets a gray color to it or you could wrap it in paper towels then soak the paper towels and let it sit for about an hour and the paper towels can give it an interesting patina.

 

[Mike Morehouse]

Andy, get a bottle of the stuff that is used to preseason cast iron cookware. Follow the directions of the preseason and don't go over your tempering temp. I have used it on cast iron and it works wonders.

 

[james terrio]

Terrio, did you use mustard to force the patina?

I've used lots of things, but have settled on a couple applications of brown spicy mustard for a mottled pattern, followed by a few wipe-downs with ordinary white vinegar. It's not terribly time-consuming and gives a nice-looking result. Here's a recent example in O1 done that way:

and an older one, also in O1:

It's clearly forced, not at all the same patina that will develop over months in the kitchen.

For comparison, here's a similar blade, same steel/HT as the other two above, with only natural patina from normal everyday use including lots of food prep - it was shipped "clean". Photo courtesy of the client.

 

[james terrio]

Educating the customer!

A great deal of my work comes from forum members who are already pretty well-educated about this stuff, so I'm lucky in that regard But you're right of course; "normal" people often don't think of such things.

 

[AVigil]

I tell them about it getting a patina and if they do not want it they can use either 0000 steel wool or a green scotch brite pad to restore the shiny metal and then keep it oiled.

Let them know it is a tool or a gun gun and it is their responsibility to keep it dry and oiled to keep the metal from oxidizing.

 

[Stacy E. Apelt - Bladesmith]

I use FC to get a darkened blade surface on carbon knives. After dipping, boil for ten minutes in water with a teaspoon of baking soda added. Rub with steel wool afterward to get the tone you like. The end result is a very pleasing older patina. It can be touched up if needed after the handle is installed with Q-tips and FC. Always neutralize well after any patina treatment.

 

[Omega Leather Works]

Maybe send them a before and after pic to show what they can expect? I'd say also include a pic of what they can expect if they don't properly care for the steel, but that probably wouldn't be wise.

As a buyer, I'd be shocked if my knife arrived pre-stained, that is, unless I expected it. I'll do my own patina, thank you, but I'm an informed buyer.

Hard to believe there are people that dumb, until I remember working in CS, then it makes sense. I suppose someone that's grown up buying and using SS can be forgiven for not expecting a patina. People have described a patina as a sign of cheapness, or even (gasp!) dirtyness.

Another thing to educate your customer on is the smell, and sometimes dark residue left behind when working with acidic food. Just be sure and also tell them that it lessens over time.

 

[elementfe]

Thanks, I really appreciate all the ideas! It's tempting to just work in stainless, except that so many people come to me all enthusiastic about "carbon steel.". I think the solution would be to just offer more options and be really comprehensive about educating costumers. A lot of them are only so interested in taking in information.... They just want to buy a knife and use it

 

[ldoyle]

I've used lots of things, but have settled on a couple applications of brown spicy mustard for a mottled pattern, followed by a few wipe-downs with ordinary white vinegar. It's not terribly time-consuming and gives a nice-looking result. Here's a recent example in O1 done that way:

That's a interesting pattern James . Could you tell how it was done ?

 

[james terrio]

"Condiment patinas" take longer to explain than they do to understand

Bring the steel to a nice crisp finish of at least 400 grit - preferably 800 or above. Assemble and clean up normally. You can patina the blade before assembly, but I find easier to do it when the knife is complete. That way you can work all the way around the finished tang at the same time you're working on the blade.

If any of your steps involve long soaks in acids, bleach etc, do it before handle assembly. Soaking can have very unpleasant effects on your glue lines... ask me how I know Then after assembly and finish grinding/sanding the handle and tang, go back and touch it up as Stacy described earlier.

Wipe it down with rubbing alcohol to help ensure it's clean, and wipe dry. Simply put little dabs of mustard (or ketchup, or anything else that's mildly acidic and viscous enough to stay in place) all over the blade and tang. Leave it sit like that for at least a few minutes. To a certain point, the longer it sets, the darker and bolder the pattern will be.

The dark lines show the outlines of where the dabs were, and are caused by the acid in the mustard and oxygen in the air reacting with the steel to cause slight corrosion.

Wash off the goop with hot water and repeat as necessary, putting dabs in different places than before. This usually takes two or three applications, depending on how dense you want the pattern to be. If you do it enough times the blade will be almost completely black, but there are easier ways to achieve that.

When you're pleased with the pattern, rinse it off again, dry it and then wipe it down with a clean cloth dipped in white vinegar (or any other mild acid) to patina the parts not affected by the mustard (or whatever) and even things out. Again, repeat to taste.

When satisfied with the results, rinse with hot water and rub down with a paste of baking soda and water, to nuetralize any acid left behind. Be sure to get into any tight corners, like where the blade meets the handle. Rinse again, protect the blade with a light coat of (preferably foodsafe) oil, and you're done.

There are many, many variations on this idea. Another way to achieve a more random, "authentic" pattern is to spritz the blade with, or soak it in household bleach. The bleach will actually corrode into the surface of the steel, pitting it slightly, and leave well-defined black marks on/in it.

Anyway, a search will reveal dozens of different ways to do it; they all work basically the same way. Experiment and have fun! (follow normal safety practices.)

 

[elementfe]

This one was done by dabbing it on with my finger- just letting it stick a bit as I pulled it away.