Forcing an artistic patina

I'm intersted in trying my hand at forcing an artistic patina. I have a CJA Honyaki with a beautifful hamon, and I find that a normally developed patina actually detracts from the hamon because it doesn't follow the hamon line. My thoughts are to trace the outline of the hamon with a with a protective layer of some kind (petroleum jelly?) and then put some blood on it to force a nice blue patina. Then invert the process with some other medium (acidic perhaps) to force a different color patina on the other side.

My question is - has anyone done this? Would it work? Would normal use just end up undoing the artistic patina over time?

If there is blade without patina on it, it will patina from use. If there is blade with patina on it, use may change that patina as the different items affect it.

Read through the entire "My favorite color is BLUE!.............A patina thread" stickied in the upstairs Kitchen Knife forum. There are some dead picture links, but plenty of other images of forced patina and ways to do it. Mustard seems popular.

I think I remember reading in that thread that forced patina doesn't last, if you're using the knife often enough with foods that will react. No harm in trying it though, if you just want to experiment.

Thanks. I'll check that out. Once a patina is built, doesn't that act as a protective layer that decreases reactivity over time, ergo less change to the patina?

guitarmanchu said:

Thanks. I'll check that out. Once a patina is built, doesn't that act as a protective layer that decreases reactivity over time, ergo less change to the patina?

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Yes, but some foods will strip the patina. On another note, I find forcing a patina on any monosteel rather blasphemous...especially so on a honyaki.

Well, the patina acts as a protective layer to a certain extent, but it's hard to generalize about how that layer changes over time, because knives can vary in how reactive they are. Also as noted above, some foods are aggressive in removing/changing an existing patina.

I guess you could stay away from the more acidic foods and protein if you want to preserve a forced patina. Me, I just let the natural patina develop. All three of my carbon-clad knives are pattern-weld damascus finish anyway, which is patterned enough without forcing something else.

If I owned a honyaki knife I wouldn't force a patina pattern either. The hamon is the big aesthetic feature there, and a natural patina looks better along with it (IMO). YMMV on that. I've learned from reading here that different people have different ideas about knife aesthetics.

This might be interesting: http://www.kitchenknifeforums.com/showthread.php/30480-Acid-etched-Tojiro-for-a-Christmas-gift

Well, on this one the hamon is especially beautiful, and the patina that's been forming has been masking it.

guitarmanchu said:

Well, on this one the hamon is especially beautiful, and the patina that's been forming has been masking it.

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Then you need to keep letting it build...or keep it polished if you really want to see it

In my rather limited experience with honyaki--I've only owned 2 though I've handled a few more--the area in the hamon will patinate slightly differently than the rest of the blade.

This will only work on REAL honyaki knives, on a moonless night, The blood must be mixed with the tears of a virgin. Or you can just use 5% vinegar on any old week day, and make your hamon pop out.

Seriously, you dont really sound like a polisher / smith so.....why would you even want to risk your fine blades wellness like that? And.....why would you call this "creative" ? I mean, obviously, the blade was made by another, the hamon line is a product of the making process, and patination is just a product of regular usage. What is so creative about that? It may be "craftsy" but I think "artistic" is a very big word here.

You want to get "artistic"? try etching a design on a slab of copper - Hats off on my end - even if you dont get it right the first time. But forcing a patina? common....:2cents:

Well obviously I meant making the patina follow/accentuate the hamon. Maybe "controlled patina" is a better word to use. My objective here is to prevent the patina that naturally forms from negating the beauty of the hamon pattern.

what you describe can be done, but you have problems with this concept.

if its the natural hamon you are wanting to accentuate then essentially any acid or staining agent will cover it naturally because the blade is all the same steel if it were Damascus it would bring out the difference in the metals. being a hamon is created by different heat in the same kind of steel it will all react the same way,
best option for it is get some super duper fine sand paper (if needed) and keep the blade well oiled and polished, anything else will patina and hide it.


alternatively if you just want to keep the pattern but dont mind actually hiding the hamon, you could remove your handle.(or not) paint the hammon with fingernail polish (use a bright color so you can easily see it when it comes to removing it later)
and then make your knife rust, you want a light orange rust and a decent coating but not any pitting, so make it rust (there alot of ways) but uniformity is what you want, and then once everythings got a nice orange coat soak it in vinegar or something acidic the thicker Fe3 layer the better your conversion will be and last, when you put it into an acid like vinager it will turn to Fe2 and be semi protective and your hamon will be left in tact at that point you could use some other agent to stain the hammon differentially from the rest of the blade.

note with use the blade patina can wear off. another option would be to do the above but use nitric acid to blue the knife, not sure what to coat the blade to protect the hamon from the oxidation from the nitric acid tho. and hot nitric acid bluing is kinda a nasty dangerous process if your not used to working with the stuff