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Playing with Ferric Chloride

Dan Rice

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A while back I posted some questions about ferric chloride, specifically the MG Chemicals brand since the Radio Shack in my area doesn't carry any. I did end up buying some from Amazon. Nobody seemed to be familiar with that brand, so I thought I would post the results of my attempt to etch a simple makers mark on a couple of blades.



This stuff seemed quite inexpensive, at $12.95 for a liter on Amazon: http://www.amazon.com/MG-Chemicals-Ferric-Chloride-Liquid/dp/B008UH3SAE/ref=sr_1_1?ie=UTF8&qid=1418829234&sr=8-1&keywords=ferric+chloride It's even cheaper if you get a 4-liter container for $32.95. I have never used any kind of ferric chloride before, so I don't know much about it. This is labeled as a "ready to use solution," not straight-up ferric chloride. The ingredients listed are iron trichloride, iron dichloride, and hydrochloric acid. The label also says "42 degrees Baumé," which seems to be a measure of density.



I coated a blade with beeswax, and probably put it on much too thick at first. I tried using a tool I made similar to a tiny chisel to scratch my initials in, but later discovered that it worked a lot better to just use an awl.



Using a mason jar as my container, I poured in a little under 200 ml of the ferric chloride solution, then topped it up to about 800 ml with water. Those that use the Radio Shack solution usually recommend mixing it 1:4 with water, but my mixture was more like 1:3. Distilled water is usually recommended, but I couldn't find any at the store so I used tap water. I don't know if that might have made a difference in the results.



This was the result of leaving the blade in the solution for an hour. Possibly because of surface tension or some other factor, the solution did not get down into the grooves in the wax and some areas were not etched at all. The un-etched areas were dry and shiny when I took the blade out. I scraped the wax off and reapplied a thinner layer and scratched out the marks again. When I checked it half an hour later, the same thing was happening. To try to fix it, I used the awl to drag beads of the solution onto the cuts in the wax and poke them down. Sounds desperate, but it actually worked.



I also prepared another blade with a much thinner coat of wax than the first one. It's a little seax, so I used Saxon runes for my initials. I had to do the same trick with the awl on this one to get the solution down into the cuts.




This was the result of etching both blades for another hour. The etching is not very deep. Deep enough, but considering that some parts of it etched for more than 2 hours, the solution probably did not need to be diluted that much. Which means it might not actually be a bargain compared to what Radio Shack carries.


But it did work, and I can finally put my mark on my blades now. This was my first time trying to etch anything, so any advice on what I might have done wrong is appreciated.

Never walk

away from home

ahead of your axe and sword.

You can't feel a battle

in your bones

or foresee a fight.


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That's an interesting post...I never thought to just use straight acid to etch a mark.


I use a salt water etching method that works very, very well. As a matter of fact, I believe the tutorial is still up in the fit and finish section.


Yep, here it is!




If you have access to any form of positive and negative electricity (even a 9v battery from my understanding!), I'm betting you'll have much better results with the salt water. Give it a try and let us know how it compares for you?

Edited by C.Anderson

Slow is smooth, smooth is steady, steady is fast, fast is deadly... Erik R.

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For the kind of etching you're trying to do, ferric chloride is not the first acid recommended (since it's technically a salt, anyway). Nitric acid is traditional for this use. Also traditional, as you have discovered, is a means to keep the bubbles off the etched surface since they block further etching. A feather is the recommended tool, with the blade usually laid flat in a shallow dish.


I'd follow Chris's tutorial for etched marks and save the ferric for etching pattern-welded blades.

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Thanks for the tips, fellers. I've seen the electric method before but haven't tried it yet. Great tutorial, Chris. That would probably be simpler, especially if I had some stencils made. I have read about etching in a few books, but I don't think any of them mentioned getting rid of the bubbles. Or maybe they did, and I forgot. I have chickens, so fortunately I have a pretty good supply of feathers. I'll look for some nitric acid, since I would like to larger and more complex etched designs on my blades. I got the ferric to use on some cable damascus, but figured I'd try it out on etching a mark since I had it around.

Never walk

away from home

ahead of your axe and sword.

You can't feel a battle

in your bones

or foresee a fight.


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I think you can probably save yourself some trouble, by building a little wax wall around the are you wish to etch, and just pour in a few drops. Makes keeping an eye on it easier, you're not immersing the entire blade, you can brush the bubbles easier, etc. As suggested in the marking tutorial, hook one wire to the blade, and another on a q-tip soaked with your electrolyte, and use the current to speed process.

The Tidewater Forge

Christopher Price, Bladesmith

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I would second Alans recommendation on the use of Nitric for deep etching on steel. Ferric is ok for bringing out the pattern in damascus but for a really deep etch its not very good. It fairly quickly develops a sort of black sludge in the etched area which then subsequently stops the etching action. I never had the good results on steel I get with ferric as on nonferrous alloys


I also tried electro etch with either, saltwater, vinegar+ salt, salt + citric. with all these electrolytes there is also the problem of a black residue forming in the etched grooves which will slow or stop the etching action after a while. With some trials i found that an addition of about 10-15g of potassium nitrate to the electrolyte solution results in a cleaner etch. With the addition of KNO3 bubbles are produced not only at the kathode(Hydrogen)) but also on the anode (possibly oxygen) which then clean the black residue constantly away.



I do a lot of etching , mostly for jewelry purpose and I use ferric only for nonferrous like Brass, copper, Nickle silver, Bronze etc. on this it does a splendid job. Even better if you do it with an addition of citric acid which then is called "edinburgh etch"


Instead of scratching the desigh into wax or asphaltum laquer I use the Toner-transfer method. .The image is printed with a laser printer and then transferred by heat onto the subject. Can be done with either Ironing or a laminator. Just google "Toner Transfer" and you will get numerous results. There is also a special paper which is used for the process, its calles Press n`Peel or PNP blue. With some trial&error you can also use other papers. I personally favor the sliconized paper thats used for backing stickers. If the temperature is right all of the toner is cleanly transferred to the metal.



Here is an example of a small copper plaquette before sawn and mounted which i did for a friend with this technique so you can see whats achievable with the toner transfer method. Size is a bitt less than an Inch.


Toner transferred:



after etching: all the details ate there but I was not satisfied with the appearance of the negative image so I inverted the picture and did a second etch, which then looks much more like the original picture after patination.






You can get some nice results with the toner transfer method, these were all done with ferric and them mounted in a turned wooden base.






got some bubbles trapped on this one, not the cleanest etch but still nice.




a certain fondness for skull motives cannot be denied :








So up to a certain extend almost all you can print you can etch. The finer the details the less deep you can go because of "underetching" you will loose very fine lines when going too deep. With thicker lines you can etch fairly deep without having to worry.



Best regards






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