Ferric Chloride question.

[bc2573]

Ok, I have been doing some reading on this board about Ferric Chloride etching and the more I read the more confused it get. I just completed a knife build for myself. Before attaching the handles I had etched the blade but was less than thrilled with the results.

Let me tell you what I did.

1. I cleaned the blade with acetone and only handled with latex gloves.
2. I opened up a brand new bottle of ferric chloride and poured about half of it in a glass container.
3. I put the blade in the glass container completely submerging to the tang.
4. I let it etch for 5 minutes and removed.
5. I took it out and cleaned washed it with hot water, and lightly sanded with 600 grit sandpaper (which took it back down to bare metal instantly).
6. So I cleaned it back up and dropped it in the solution for 5 minutes.
7. I pulled it back out and washed with hot water and skipped the sandpaper step.
8. I applied my makers mark and submerged in the etchant solution again for 30-40 minutes.
9. I removed, neutralized, and polished with Flitz metal polish.

This is the finish I got when I was done.

It is a dull light gray color. I decided to live with it at first but when shaping the handle, I inadvertently got into the spine and took a small section of etch off of the blade. So now I am faced with having to fix that spot by taping off that area and applying etchant with a Q Tip and blending, or sanding the blade back down to 600 and re-etching the entire thing. I am thinking about the latter since I wanted a darker finish on the blade. Here is the finish I envisioned on this blade to begin with.

So...... now that you've see what I am trying to accomplish and assuming I sand her back down and re-etch how do I need to approach it? I've read multiple threads with people saying they cut the acid with distilled water 50/50, and some saying they use straight acid. I've also had a couple of makers tell me to heat the etchant in some warm to hot water by putting it in a mason jar and dropping it in a pot of hot water (like one would warm up a baby bottle). I've been told the water/FC mixture will etch darker, and I've been told that warming it up significantly will make it etch faster and darker. Also keep in mind that I etched for 40 minutes last time. If I do any of those things to improve the etch, will I need to cut down my etch time? I don't want to burn the blade up, especially now that is has a $75 piece of presentation grade Kao attached to it.


Any help will be appreciated.

 

[uxo2]

I use it straight and at room temperature.

Some steels etch faster than others.
Others take a completely different tone regardless of dip time.

For the dark color you seek... Lightly buff off the rough scale with a strop.


If you want a even finish... A re-dip would be best.
Q-tip will be challenging to get a even finish but might show up as a Blem to the sharp eye.

 

[bc2573]

Probably going to do a re-dip maybe tonight. I used straight FC (room temp) the first time for 30 minutes and it did not give me any dark metal at all. How is cutting it with distilled water going to help me etch it darker? Remember I'm learning and may not realize the chemistry so I'm prone to ask questions.... ; ).

 

[uxo2]

Cutting it with water?
Never tried or heard of it..


If you have a Donor blade to experiment with. Then try it to see if it will work.

 

[bodog]

I'm more worried about the squared shoulders and lack of smooth transition from the really thin tang to the blade, but if that's one of your completed knives in the picture you should be teaching us rather than seeking advice.

Anyway, what's the steel. It won't do that much to stainless steels and it should be pretty easy to etch carbon steels. Tool steels being in the middle shouldn't be too much of an issue. The results will go from a dark charcoal gray, almost black to mottled gray/black to just a rough gray, depending on the amount of corrosion resistance.

I wouldn't use a q-tip to try to fix it if it's still just a blade with no handle. Buff/sand it off and do it again. Unless you're just not that patient. Depends on whether you want perfect results or not. And maybe consider using a little more radiused transition to keep the blade from breaking from the tang once the handle is put on.

If I had to guess, and my guess means jack $#!+, I'd say that was D2 steel or something similar. If it's carbon steel then the acid is too weak and if it's something more stainless then you did a good job of getting an even coloration and it might not get much better.

 

[bodog]

Cutting it with water?
Never tried or heard of it..


If you have a Donor blade to experiment with. Then try it to see if it will work.

If you get it in crystal form then it definitely needs water added. If you get it in concentrated liquid form then how much water you add will affect just how aggressive the acid is. Some people want the acid to take a little longer to work so the maker has more control so they dilute it.

 

[bodog]

By the way, your maker's mark looks really classy.

 

[eKretz]

I agree with Bodog's points on the steel type. Carbon steel will literally turn black really quickly when using FC at a high enough strength. If you are using a stainless or near stainless alloy you don't want to use FC. Try Hydrochloric (or Muriatic, same thing) acid. Also, don't polish after etching - you'll just remove the etching. I usually just rub the loose stuff off with a wet cloth and rinse, then neutralize with baking soda/water.

 

[bc2573]

I'm more worried about the squared shoulders and lack of smooth transition from the really thin tang to the blade, but if that's one of your completed knives in the picture you should be teaching us rather than seeking advice.

Anyway, what's the steel. It won't do that much to stainless steels and it should be pretty easy to etch carbon steels. Tool steels being in the middle shouldn't be too much of an issue. The results will go from a dark charcoal gray, almost black to mottled gray/black to just a rough gray, depending on the amount of corrosion resistance.

I wouldn't use a q-tip to try to fix it if it's still just a blade with no handle. Buff/sand it off and do it again. Unless you're just not that patient. Depends on whether you want perfect results or not. And maybe consider using a little more radiused transition to keep the blade from breaking from the tang once the handle is put on.

If I had to guess, and my guess means jack $#!+, I'd say that was D2 steel or something similar. If it's carbon steel then the acid is too weak and if it's something more stainless then you did a good job of getting an even coloration and it might not get much better.

Thank you for the compliments. Probably not deserved as I am definitely a newbie to blades. The steel is O1. I etched it the first go around and got the silver finish you see in the above pics, which I was not happy with. Because I got into the spine while shaping the handle and messed up the etch anyway I took you guys advice and decided to redo the blade. When I got home last night I went to the shop and sanded down the blade to 600. It took a little work but I finally got the old makers mark sanded down. I took my Ferric Chloride in the house and put it in a mason jar and then put the jar in a boiler on the stove with some steaming hot water. I warmed the FC up for a few minutes and pulled it and headed to the shop. I could tell it was good and warm. So I took my little etching glass and put maybe 2-3 ounces of distilled water in it and added the FC. I dunked the blade and counted to 20 and removed it. I could tell right away it was etching strong. I neutralized it and cleaned all the black off. I then put my makers mark on the blade and back in the FC it went. I pulled, neutralized, and cleaned after 2 and a half minutes and the back in the FC for another 3 minutes. When I pulled it out the second time it was black. I'm not looking for jet black so I decided to end the process there. I sprayed her down with windex and cleaned off the black gunk. I scrubbed it with hot soapy water and then hit it with some soft cloth and some Flits and it turned out nice I think.

 

[bc2573]

By the way, your maker's mark looks really classy.

Thank you sir.

 

[bodog]

Thank you for the compliments. Probably not deserved as I am definitely a newbie to blades. The steel is O1. I etched it the first go around and got the silver finish you see in the above pics, which I was not happy with. Because I got into the spine while shaping the handle and messed up the etch anyway I took you guys advice and decided to redo the blade. When I got home last night I went to the shop and sanded down the blade to 600. It took a little work but I finally got the old makers mark sanded down. I took my Ferric Chloride in the house and put it in a mason jar and then put the jar in a boiler on the stove with some steaming hot water. I warmed the FC up for a few minutes and pulled it and headed to the shop. I could tell it was good and warm. So I took my little etching glass and put maybe 2-3 ounces of distilled water in it and added the FC. I dunked the blade and counted to 20 and removed it. I could tell right away it was etching strong. I neutralized it and cleaned all the black off. I then put my makers mark on the blade and back in the FC it went. I pulled, neutralized, and cleaned after 2 and a half minutes and the back in the FC for another 3 minutes. When I pulled it out the second time it was black. I'm not looking for jet black so I decided to end the process there. I sprayed her down with windex and cleaned off the black gunk. I scrubbed it with hot soapy water and then hit it with some soft cloth and some Flits and it turned out nice I think.

Haven't ever messed with O1 but I'd have to think you wouldn't have much issue getting the blade as dark as you wanted. If you want it darker then don't dilute the acid you're using because it doesn't seem strong at all at this point. I just etched M4 which has more chromium than O1 and it was really dark gray within 5 minutes. I didn't buff it, just rinsed and neutralized. I rubbed the bevels near the spine with a tiny bit of oil to get some contrast. O1 should be much easier.