# Thinning damascus



## Ennjay (Nov 18, 2011)

Forgive the possibly newbie question.

With knives like the Tanaka R2 damascus, how do you thin behind the edge? It seems to me that the textured damascus would prevent you from thinning easily - you'd have to take off a whole bunch of material and make the knife look pretty ugly doing it.

Or am I missing something?


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## EdipisReks (Nov 18, 2011)

ideally one would thin, polish, then re-etch. it's one of the hazards of buying that kind of knife.


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## GlassEye (Nov 18, 2011)

You could also use fingerstones instead of re-etching, though that would look different than original. I have yet to get some fingerstones, but plan on it at some point. In my experience, the Tanaka damascus had less reactivity/rust problems when I polished out what was etched; looks better too, in my opinion.


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## slowtyper (Nov 18, 2011)

How exactly do you "re-etch"?


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## EdipisReks (Nov 18, 2011)

slowtyper said:


> How exactly do you "re-etch"?



acid. i use a combo of PCB etchant and 12 molar HCL, but i work at a basic research biology department, so i have access to happy, happy acid. regular PCB etchant (available at radio shack) and white vinegar, in a 50/50 combination, inside a PVC pipe or glass pitcher sized correctly to keep the knife nice and upright, works great. just keep it in until it looks right. dispose of the acid by pouring it down the drain _VERY_ slowly with the water running, and treat the knife with a baking soda/water slurry when you're done. it's really not a big deal, just wear rubber gloves and safety goggles. even my mix doesn't do much more than turn any affected skin yellow, as long as it doesn't get in your eyes, if you get it under the tap quickly.


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## slowtyper (Nov 18, 2011)

Cool, thank you. I only have one damascus blade but I'm not thinking of thinning it....however I will try that when the pattern eventually starts to fade from regular sharpening and when I have some time to kill.


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## mateo (Nov 18, 2011)

EdipisReks said:


> dispose of the acid by pouring it down the drain _VERY_ slowly with the water running



Err.. isn't this illegal in most states?


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## EdipisReks (Nov 18, 2011)

mateo said:


> Err.. isn't this illegal in most states?



no. dilution is the solution. it's what any high school chemistry lab would do. like i said, very slowly.


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## Hattorichop (Nov 18, 2011)

EdipisReks said:


> no. dilution is the solution. it's what any high school chemistry lab would do. like i said, very slowly.



High school kids are etching damascus these days? 
Boy did I miss out!


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## slowtyper (Nov 19, 2011)

Can you show us how to cook meth next?


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## Andrew H (Nov 19, 2011)

slowtyper said:


> Can you show us how to cook meth next?


Isn't that what Breaking Bad is for?


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## tk59 (Nov 19, 2011)

EdipisReks said:


> no. dilution is the solution. it's what any high school chemistry lab would do. like i said, very slowly.


+1. People use concentrated acids and bases all the time as cleaning agents and they mostly just get flushed down the drain with plenty of water.


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## EdipisReks (Nov 19, 2011)

Hattorichop said:


> High school kids are etching damascus these days?
> Boy did I miss out!



high school kids in lab use strong acids and bases, which was my point. tk's completely correct. a 38% HCL solution isn't harmful once it becomes .005% solution. same with ferric chloride (PCB etchant). the minute amount of dissolved steel in this application also isn't a big deal. PCB etchant that has been used for its intended purpose, etching PCBs, should be disposed of through a chemical recycler, but that is because of the CuCl2. one could always precipitate out the ions, but that's more than i feel like doing at home, as i don't like lye. i also don't etch PCBs at home. if one is really concerned, a mildy basic solution of baking soda and water poured with the acid would do the job.


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## mateo (Nov 20, 2011)

EdipisReks said:


> no. dilution is the solution. it's what any high school chemistry lab would do. like i said, very slowly.



I thought this kind of attitude regarding pollutants went away about 30 years ago. My original remark was a little tongue and cheek, but you really should not just pour it down the drain... without precipitating the solution to render it safer.


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## mateo (Nov 20, 2011)

EdipisReks said:


> should be disposed of through a chemical recycler, but that is because of the CuCl2. one could always precipitate out the ions, but that's more than i feel like doing at home,



Forgot to read the entire thread before replying... :dontknow:


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## EdipisReks (Nov 20, 2011)

the tiny amount of steel removed in etching the blade isn't going to make any difference. etching PCBs is something different.


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## Ennjay (Nov 23, 2011)

EdipisReks said:


> ideally one would thin, polish, then re-etch. it's one of the hazards of buying that kind of knife.



Thanks. That makes sense. Sounds like a lot of effort though...


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## jmforge (Nov 26, 2011)

slowtyper said:


> How exactly do you "re-etch"?


 You can also heat up some white vinegar on the stove and brush it on the infested areas. :doublethumbsup:


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