How to get Damascus contrast back?

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chocolatecurry
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How to get Damascus contrast back?

Post by chocolatecurry »

Hi All,
Hope this is close enough to a sharpening question. I've had a Fujiyama W1 Damascus blade that I've used daily for almost 5 years now. It had a really nice factory contrast but over the years I've totally lost it by cleaning patina off with Flitz. I recently picked up a Tanaka B1 240 that reminded me how cool the original finish was and I was wondering if you all have any advice for getting that finish (or close to it) back on my 210? Finger stones? Stone powder? The new blade has on the soft part of the Damascus that doesn't look like an etch but rather some type of polish.

After a month or two of use:
IMG_0098.jpg
Flitzed:
IMG_0102.jpg
Factory finish on a new Damascus blade by Tanaka:
IMG_0103.jpg
Thanks!
taz575
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Re: How to get Damascus contrast back?

Post by taz575 »

Ferric Chloride is often used to acid etch blades, which the steel reacts to by forming dark oxides on the blade, as well as actually removing metal if left long enough. Its available on Amazon, add 1 part of acid to 4 or 5 parts water in a plastic container to make an etching solution that can be reused a lot. The acid makes the surface of the steel react (like a fast, hard patina) but isn't very deep. If you want a deeper etch, you need to remove the oxides to let the acid get to the steel to continue to get more depth since the oxides form a "skin" over the steel and slow the acid process down (Ie the dark black R2 Damascus blades from Tanaka where the blade is darker and the ridges are felt more). Think of etching as a fast patina! The steel reacts, but does so more evenly and consistently and makes the patina process a little different during use.

You can etch until it's darker, and then use very fine grit sandpaper, finger stones or even non woven abrasive pads on a hard backer, to remove some of the oxides to get back to the lighter look like a newer one with the blade more shades of grey rather than black and silver and some depth to the etch. Harder material/pads will have more contrast, the softer non woven pads will lighten the whole blade since they will get into the lower portions more. The dark (deep) etch will leave the surface rougher and will etch deeper, so you would want to polish the surface a bit to get it smoother feeling for less drag in food, but you may feel the layers more in like onions (My Tanaka R2 does this). Or you can do a quicker etch, like say 30 seconds instead of 2 minutes depending on the strength of your solution to get the look as well, which will leave more of the surface polish intact/less effected by the acid depth wise and a quick polish with very fine abrasive will get it looking smooth again. A weaker solution is better here since it acts slower, so it will be easier to etch for a bit, like 20-30 seconds, pull out, see if you like it and keep doing short etches until you get the color/depth you want. If you use a very strong mix, it will darken very quickly and may go deeper/darker than you want and then you have to polish it even more.

Your flitzed blade looks pretty good to me (similar to my Tanaka Sekiso when new), but if you want more contrast, a quick etch will probably get you there! I have the Sanaka Sekiso knives and used some non woven abrasive pads to remove the patina and prep the surface for etching and ends up looking very much like your flitzed blade before etching.

Thoroughly wash and degrease the blade with soapy water and then acid etch. The acid etch solution will stain things an orangey rusty color, so make sure to protect under the acid container! I put heavy tinfoil down on the counter and put the acid container on the tin foil right near the edge of the sink. This lets me wash the blade with hot, soapy water to degrease, put it into the acid etch and when I remove it and bring it over to the sink to neutralize, all of the drops go onto the tin foil and not counter. I neutralize with hot water and then quickly dry with paper towels and coat with mineral oil, but other people use windex or other solutions to neutralize the acid. When drying, some of the oxides will wipe off onto the towel, so the etch may get lighter and now be as even, so keep that in mind! You may have to go a little darker to take that into account so you can even up the surface afterwards finish wise. You can always use very fine sandpaper and a cork backer or something like that to do a quick polish of the blade to even out the finish or the very fine non woven abrasive pads (usually grey or white color, not the maroon/green in hardware stores).

Damascus shows because each steel reacts differently to the acid. Some steels stay bright and shiny due to higher nickel content, others with higher carbon content turn darker, others with chromium and/or lower carbon may be more grey/silver. So coloration/contrast is often depending on the steels used. When there is a little depth, you can re polish the high points to get them shiny again and leave the duller/more matte look in the lower portions. In your last pic, you can see the higher points are polished more and darker appearing. So the core edge high carbon steel will be dark grey, the mild steel cladding will be more silvery and medium grey and you can polish the high points to a shinier look and leave the matte silver in the grooves and the edge dark. A hard backer/abrasive will leave the tops shiny, but a softer abrasive, stone slurry, non woven abrasive will get into the different depths and even out the finish more, but still show contrast.
salemj
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Re: How to get Damascus contrast back?

Post by salemj »

I may try experimenting with a "lesser" blade with very subtle damascus (Ikeda KS) and report back. My first inclination is to try 2-3k sandpaper (from an autobody shop, rinsing regularly) or 5k+ stone powder, but I may also try a diamond paste.

Also, nice knife! I wonder how often you've sharpened it over the years—it still looks great.

Tim responded in the meantime with his wonderful expertise, but he actually seems to have a similar approach in his last paragraph. My sense is that, if you are not going for the etched look, you can probably get your knife feeling more like the original using sandpaper. The nickel reference here (or alloy reference) is key: it is one reason why a good kasumi can show up on a carbon blade with a 3k stone: the core polishes to nearly mirror, but the sandwich grips and holds the grit and remains hazy. I find sandpaper "cleans" blades very well, especially carbon blades that have been treated with Bar Keepers or Flitz, in a way that removes the kind of grey haze those products can leave by lifting the patina a bit (and also just removing more grime). The negative is that sandpaper is an abrasive, and even at 2-3k, you may not appreciate the minor hairline scratches. Powders and such 5k and above also leave scratches, but they can be much harder to see with the naked eye. :)
~Joe

Comments: I'm short, a home cook, prefer lighter, thinner blades, and own mostly Konosukes but have used over a dozen brands.
chocolatecurry
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Re: How to get Damascus contrast back?

Post by chocolatecurry »

Thanks all! I guess I never thought about sandpaper and since I use JNats the most it's sort of a foreign concept. But I've definitely noticed synthetics provide a great contrast depending on the knife. Taz's suggestions make me want to either leave it polished or turn it over to a professional lol. Taz any thoughts about natural stone slurry or some kind of finger stone? Same concept I guess but natural stones sort of a unique characteristic depending on what you use.
taz575
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Re: How to get Damascus contrast back?

Post by taz575 »

Natural stones are nice, but can be a pain with different steels. I would etch it and try some 2000 or 3000 sandpaper if you want shiny contrast or really fine non woven pads and see how you like it. Stones and slurrys are a while different animal and harder to duplicate.
Kalaeb
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Re: How to get Damascus contrast back?

Post by Kalaeb »

Have any of you guys done the hot coffee method? I wonder if it would create less of a tactile feeling etch like the pcb and just more visual?

I have been wanting to play with it, but have not found the time.
salemj
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Re: How to get Damascus contrast back?

Post by salemj »

Kalaeb wrote: Thu Jan 13, 2022 1:00 am Have any of you guys done the hot coffee method? I wonder if it would create less of a tactile feeling etch like the pcb and just more visual?

I have been wanting to play with it, but have not found the time.
Never heard of this. Can you provide info?
~Joe

Comments: I'm short, a home cook, prefer lighter, thinner blades, and own mostly Konosukes but have used over a dozen brands.
taz575
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Re: How to get Damascus contrast back?

Post by taz575 »

It darkens the steel a lot and brings a little more contrast after the etching is done. But it rubs off quicker than a ferric chloride etch. Most people do an acid etch and then a coffee etch.
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