Blade etching.

Hi there
Somebody asked me to thin his Forgecraft, round spine, choil, bla bla bla. Also I have to mirror polish bevels and etch top part with ''bricks''. So I need to buy etching agent.

Is this one good?

http://www.ebay.co.uk/itm/1kg-Ferri...Equipment_Lab_Supplies_ET&hash=item3369ccf959

Can you give me more info about it? Is it safe? How can I store it safely? Do I have to mix it with water? Is 1 l enough? Thank you in advance.

 

Safe how? It's an acid......so in that regard, it's not "safe" per say. However, I've gotten it on my hands and it's not going to dissolve your hands in a second or nothing like that. I try to wear rubber gloves, but mistakes happen and I'm no worse that I'm aware of.

This is the one I have:

http://www.radioshack.com/product/index.jsp?productId=2102868

I don't know the concentration off the top of my head, and I couldn't find the concentration of the one you linked to....so that could change the dilution rate I'd use......that said:

I dilute mine at a ratio of about 1:1 with distilled water. I made a PVC tube out of 3" tube with a screw on cap and a capped bottom. Have it bolted to my one work bench. The screw on cap prevents evaporation and keeps it splash free. I used two of the bottles at 16 ounces.....one kilogram according to my converter thing is about 35 ounces, so one bottle should be enough if it's roughly the same concentration as the stuff I get from Radioshack.

Hope that helps.

 

Ferric is great but for this you probably could get away with using mustard. Tape off the brick pattern and any area you dont want it etched. and use a small craft paint brush to apply the mustard. Let it set on there for 10 minutes or so. then rise it in warm water and peel the tape and you should get the desired results.

 

Randy is correct. A hot vinegar bath will also darken/force patina on your blade. A strong FC solution can cause pitting. As me how I know. I use about 15 to 20% FC to water, and longer soak times.

 

Umm, dang I feel silly for not suggesting this.

 

When we are talking carbons yeah maybe one could just use mustard, but I never managed to get there on stainless.

The results on carbons werent impressive, imho. I anyway would prefer ferric chloride. Its faster, more reliable, results are OK theres no spots like after mustard.

 

Guys I bought Ferric Chloride but it is not fluid but Some rusty very thick crystals. What can I use to dissolve it? Destiled water? I've seen Dave Martell mixing it with white vinegar.

 

At that ratio, you should have full strength etchant. I would mix as instructed, and then dilute prior to etching your knives.

 

What do you exactly mean? I should mix it as instructed and then mix it again? I would like to preapare it only once. Is full strength etchant bad for my knives?

 

It will be very aggressive at full strength. I use the prepared liquid, and at even a 25% solution I had issues with spotting, and slight pitting. Remember this is an acidic solution, and you are only looking to change color, not remove material. So if it takes you a half hour soak at a week solution, to get the nice even result you are aiming for, isn't that safer than doing it fast, with a stronger solution, and potentially doing damage?

Be safe, test. So 50gr per 100 ml, would be strong. Trust me. Try 50gr in 400ml. That is 25%of full strength. I prefer it weaker, with a longer soak. Test on an old blade, or polish up a piece of carbon steel, see how fast it etches. Don't worry if it takes a little longer. The finish will be smoother, and more even. Ferric Chloride isn't the best choice for all etching of steels. For stainless, Udderholm recommends sulfuric acid to etch damasteel. I have used sulfuric, murriatic, and nitric, on different materials. Each has its own challenge.

 

Thank you Pierre. That's the answer I was looking for. I am not chemist so this is why I wanted to be sure what I am doing. I mixed Ferric Chloride in double plastic food box with cover. I took 50g of crystals and mixed it with 500ml boiled, room temperature water. I used cloth with wool inside as the brush and I was covering blade all the time. Then I cleaned blade with steel wool, washed it in warm water and repeat whole process again. Check results:

Before:


After:

 

Very nice! looks like a nice even etch.

 

Ditto. I like the misty effect at the edge of the cladding.

 

Something else to try.

 

For carbon knives, I just use hot white vinegar, these days. I've used FC (and even stronger etchants, when I worked in a lab environment and had access to chemicals) on stainless, to good results, but I think it's unnecessary on carbon.

 

But hot vinegar will not give you even effects. For example I tried vinegar, mustard and lemon juice before. In first 2 - 3 layers everything was ok but then after next one something went wrong. Look: