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Alex Middleton

Etching question

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I know that most of you guys use Ferric Chloride for etching patterns.  Will HCl work as well, or is it too aggressive?  Also, roughly how long should you leave it in the acid when etching?

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I'm not sure about HCl but I use sulfuric acid for etching.

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Depending on how aggressive the acid dictates how long you leave it in the acid. And it all depends on the results you want. If you want topography you would leave it in a lot longer than if you were trying to bring out a hamon.

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Hydrocholoric will work. Strong vinegar will work too. Ferric is just the best solution all around for this, however. It's super cheap. $10 on Amazon. 

https://www.amazon.com/MG-Chemicals-Chloride-Etchant-Solution/dp/B008O9XMYA/ref=sr_1_1?ie=UTF8&qid=1546733582&sr=8-1&keywords=ferric%2Bchloride%2Betching%2Bsolution&th=1

Do yourself a favor and buy this, dilute it with 4 parts water, and remove a lot of variables in your etch.

As for how long: I do 15 minutes soaks, scrubbing the oxides off between them with comet or another abrasive. If a coarse pattern, I do 4-5 soaks. If a very fine grained pattern, 2-3. Neutralize with Windex. Buff lightly at high RPM with a fine grit (pink) rouge to bring everything out. Clean with WD-40. Remove WD-40 oil with rubbing alcohol. Coat with floor wax. Done.

YMMV. Luck.

Dave

 

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Thanks for the help guys.  I just forged out my first multilayer knife, I'm going to be rough grinding on it tomorrow and I'm pretty excited to see if the layers will show up at all.  Given that it is just pallet banding layered with 1095 shim stock, there probably won't be any contrast, but you never know until you try! :D

Dave, thanks for the detailed response.  If I see any contrast with the HCl I'll pick up some ferric and use your method when I finish the blade.

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Posted (edited)

FYI, the steels react differently to the acid pre and post heat treating.  The mix of steels I normally use pretty much reverse their colors after heat treat.  (ie what is bright in the finished knife looks dark before heat treating) 

Edited by Brian Dougherty
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Thanks for the heads up Brian.  I did this one to see if I could successfully pull off a forge weld (my first one ever).  The billet seemed to be right and tight so I forged it out into a blade shaped object.  Getting any contrast at all between the layers will be an added bonus.  I didn't get a chance for any shop time yesterday (my sister-in-law decided that her birthday party was more important than my hobbies) but hopefully I'll be able to get on the grinder sometime this week and see if anything shows up.  Something tells me that moving away from salvaged metal and ordering some 1084 and 15n20 is in my near future.

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It worked!  I spent a few minutes cleaning up forge scale and getting a really rough start on the bevels, the I couldn't wait anymore and dunked it in the HCl for 15 minutes.20190108_194200.jpg

Lo and behold, there's definitely some contrast between the layers.  I'm not sure if I'm going to finish this one out or not. It was supposed to end up as a chef's knife, but I didn't draw the bevels down far enough.  I guess i could maybe reprofile it into something else.  Either way, I'm totally geeked that the forge welds actually worked!

 

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When you say "drawing" your bevels, do you mean forging them?  You might consider grinding your bevels for damascus with minimal forging.  I cannot speak to any loss of strength of toughness with ground bevels, but with damascus, grinding the bevels will give you maximum contrast for your layers.  Something to consider.

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Within reason. Just get past the decarb and you'll be fine. A hardened blade will etch better.

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