Media Hot Vinegar Patina

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Looks great! How many cycles waa that? Hows the reactivity?
 
The gyuto got 3 baths and only 2 for the petty. I cut some tomatoes afterward and I got a bit of the usual smell but then it just disappeared and that was it.
 
Anyone tried this with a damascus knife, or have an idea what the effects would be on damascus? Just curious at the moment, but thinking of picking up a carbon damascus in the not too distant future.
 
Justin0505 said:
I don't have any pics of the new nakiri yet, but here's my old gyuto that was done with the circuit board etchant
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The etching solution creates much greater contrast between the metals, where the hot vinegar leaves a less obvious, more natural look that's closer to the contrast created by the polish that the shigs come with.
Neither the hot vinegar nor the etching acid impart any color. The color down near the edge you see in the pics came from where the etched layer was thinned due to sharpening and thinning and a natural patina took root. The etched metal is still just slightly reactive and it will take on some colors over time, just much, much slower than un-etched.
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Like This? ^^^
 
I might have misread that post, but I thought it was done with etching solution rather than with vinegar.
 
r_icke said:
I might have misread that post, but I thought it was done with etching solution rather than with vinegar.
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Yes, the shig was done with the PCB etchant, but it also had a light patina that developed OVER the etch.

Hot vinegar yields lower contrast, but a more "natural" look. The process takes a bit longer and obviously is very dependant on the reactivity of the steel (dont think it would work on stainless or very well on semi stainless). I just thinned and then re-etched the kitaeji nakiri that had the vinegar patina on it with PCB etchant and forgot to take pics of the vinegar finish before. Once it gets some more wear and needs another refinishing, I'll try to remember to switch back to hot vinegar and photo-document this time.

Really though, finishes on steel are VERY difficult to capture accurately in a photo and the finish is going to be different depending on the steel in your particular knife and how many cycles you do and for how long, what your level of polish was pre-etch, etc...

The best way to know what your knife is going to look like is just to try it yourself. You're not going to damage your blade (unless you fall asleep).
 
I got my Hiromoto 240 gyuto today and went to thinning it right away. I didn't thin a lot but enough to make a difference. Then I etched it with hot vinegar. So this is my homage to Dave Martell. This knife will end up in his hands one day but for now this will do.

The blade does have a small over grind near the heel on the kanji side but once thinned properly it will disappear.

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Thanks guys. I am really liking this knife so far. The AS takes a crazy edge!
 
What effect on re-activity will this have? I'm having some trouble with brunoise shallots getting dark after a few hours with my nogent..
 
panda said:
did you wash the black stuff off and that's the end result? or did you leave that on to make it all badass looking like that?
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No that is what it looked like after I wiped it off and it was dried. I was surprised as well.
 
Justin0505 said:
Yes, the shig was done with the PCB etchant, but it also had a light patina that developed OVER the etch.

Hot vinegar yields lower contrast, but a more "natural" look. The process takes a bit longer and obviously is very dependant on the reactivity of the steel (dont think it would work on stainless or very well on semi stainless). I just thinned and then re-etched the kitaeji nakiri that had the vinegar patina on it with PCB etchant and forgot to take pics of the vinegar finish before. Once it gets some more wear and needs another refinishing, I'll try to remember to switch back to hot vinegar and photo-document this time.

Really though, finishes on steel are VERY difficult to capture accurately in a photo and the finish is going to be different depending on the steel in your particular knife and how many cycles you do and for how long, what your level of polish was pre-etch, etc...

The best way to know what your knife is going to look like is just to try it yourself. You're not going to damage your blade (unless you fall asleep).
Click to expand...

Thanks for a detailed response! Will definitely try this sometime – just need a knife first that I can try it on :)

The kitaeji looks beautiful by the way.
 
Nice rdmalak!

BTW, all Hiros have that overgrind on the right side heel. Maybe it's from the kanji clean up? I don't know but it's always there and a pain to deal with.
 
just tried it on a damascus blue #2 petty via boiling vinegar bath x 2 @ 10mins ea, looks really ugly lol, i hope it works as a protective barrier! might try ferric chloride bath next time.
 
Hot vinegar works for some knives, and can have really nasty effects on others (e.g., pitting), as I've discovered the hard way (and maybe Panda has too). Room temperature for me from now on.
 
Yeah I'd be curious about any downsides to this. At minimum I assume you need to resharpen right away.
 
10min per bath sounds like a very long time for a reactive knife. It lools like it there was too much oxidation and the steel started to actually etch/ pit vs jusy patina.

Remember: any time you're trying a new steel: small steps and frequent assessment.

Few things: looks like there where a few uneven spots due to contamination or uneven finish. its very important to get an even finish (polish) over the whole blade first and then to to remove all contaminants: first with soap and water, then with alcohol or acetone.
Inbetween baths, give it a good scrubbing w/ soap and water and extra extra fine steel wool. Then degrease again w/ solvent.

The finish that you get will likely not be super high contrast but soft and subtle shades of silvery grey. The steel will be less reactive, but will still patina further with use.

If you clean the blade back up and deslcided to guve tge pcb etch a try, follow Daves directions in the knowledge sub forum (esp re: safety) very closely an remeber that the reaction will happen MUCH faster( in seconds, not minutes.)
 
I've never really timed the bath time, I just watch the reaction. Using a clear container (like tall jar, jug, or vase) works well. Once i see the reaction start to to slow down a bit (fewer bubbles) I pull it out and give it a quick rinse and dry to stop the reaction and make sure that it doesn't continue in an uneven pattern as the blade dries. Then, I get the vinegar back on the heat to bring it back to a boil. While it's heating, I give the blade a more thorough cleaning / scrubbing and then dry and de-grease. Usually at some point before I'm done cleaning, it's time to take the vinegar off of the heat (you gotta watch is because it will boil over very easily).
Again, once you figure out a good bath time / when to pull it, the safest way to develop thicker/ more stable patina is by increasing the number of baths, not the length of bath.

That's my process's pretty much the same as in the video. No real "tricks" just watching the reaction, and building up bath times slowly till you get a feel for it, etc.

With my Shig's and more reactive knives, I've used the hot vinegar bath as a way to set a base layer and make establishing additional patina a more forgiving process, but then I've continued to develop additional patina either through natural use or additional forced methods.
Once such method for additional patina / more interesting color and pattern is to heat up the blade up by pouring on hot water and to then apply a thin layer of raw animal juice (beef blood works well), let it dry a bit, then rinse again under hot water. You will usually start to see the colors as the blade dries after the rise. Through experimentation, you will get a sense of where the line is between developing pretty colors / building up a protective layer and going too far and entering the realm of red/brown rust and pitting (just like with the vinegar bath).

If you want quicker and more dramatic results, then try the PCB etchant/ vinegar solution method outline in great detail by Dave: http://www.kitchenknifeforums.com/showthread.php/6474-Damascus-Knives-amp-Re-Etchng - that process remind me much more of developing a photographic print in a dark-room: you actually see the charge / reaction happening right in front of your eyes, so learning when to stop is a bit easier. In general, it's a less fiddly process. I've got pics of my latest results on the last page.
 
I received my Tanaka blue#2 135mm petty today. I rounded the Spine+choil & decide to use it as guinea pig for etching. I use 40% PCB etchant/60% vinegar solution then following Dave's instruction, wipe clean/dry, lightly polish with Flitz, finish up with 0000 steel wool and Camellia Oil . the result is quite nice....silver with dark gray color!


you can see core steel(Hagane) & soft steel cladding(Jigane) clearly from top of spine
 
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