Black knive blade ???

B

BIGJEEPMAN

Member
I would like to know how to make my knife blades black, or dark colored. I have been making knives for friends and family for the last 2 years. Lately I have wanted to make some black knives. I have a few ready to temper that would look really cool with black blades. I would like to know what to use and how to do it. I don't know if they use acid, or die, or if they bake the blade some how. Thank you
 
What type of steel are you using? There are a few different options based on the answer to that question.
 
The steel I am using is leaf spring steel. I have a bunch of spring steel knives cut out that I need to finish before I move on. The next batch will be 01 or d2.
 
You can probably blacken them with a ferric chloride etch, that is circuit board etchant like you can get at radio shack, if there's any left. Mixed 1 part etchant to 4 parts distilled water is a good general solution.

Or there is the birchwood casey or such cold bluing solutions. In either case, to get the best most even finish, the quality of your blade finish will make a huge difference. Do the best job you can on the blade before the etching or bluing and you'll get the best finish.

Then you can do a variety of other topical coatings. Powder coat, baking lacquer, cerakote and others. Probably best to send it out to a shop that specializes in those things for best mix of quality/cost savings. The baking lacquers sold by Brownell's and others might be the exception as they are probably pretty straightforward to do at home.
 
John, how smooth of finish do you recommend before using the acid etch? Is 600 grit enough or do you recommend something finer?

Thanks,
Aaron
 
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I have taken to 400 grit and etched in ferric chloride with good success. Just make sure the blade is super clean before etching.
Here is an example of the results taking it to just 400 grit before
31b18cb64a906232904b0d8fa1a718a2.jpg
 
Thanks Justin.
Is acetone adequate for cleaning? Or should I pick up some denatured alcohol? I read somewhere that the acetone might leave a residue?

-Aaron
 
Aaron, the ferric works good like the guys have mentioned, but if you want another option, regular vinegar will give a nice look too. Bring it to a near boil in the microwave or on the stove and soak blade in it for 10-15 minutes. Rinse and scrub blade down with an old toothbrush, then repeat. Three or four cycles usually gets it pretty black. But, even easier is to run down to sporting goods store or gun shop and get a bottle of Birchwood Casey Super Blue. Only costs $7 or $8 and comes out very black. Very easy to do and fairly durable.
 
aelgin said:
Thanks Justin.
Is acetone adequate for cleaning? Or should I pick up some denatured alcohol? I read somewhere that the acetone might leave a residue?

-Aaron
Click to expand...
I clean the blade good with dawn soap and water then dry and wipe down a couple times with denatured alcohol, I have heard the same about acetone but no first hand experience.

JP
 
Is Birchwood Casey Super Blue just a wipe on cold application and let it dry? No baking or anything?
 
Justin Presson said:
I have taken to 400 grit and etched in ferric chloride with good success. Just make sure the blade is super clean before etching.
Here is an example of the results taking it to just 400 grit before
31b18cb64a906232904b0d8fa1a718a2.jpg
Click to expand...

That is what I am looking for, I love the black and orange. Where do you get ferric chloride? I guess I am not the only Aaron around here!!
 
If I'm not mistaken ferric chloride is another name for PCB etching solution. You can buy it at radio shack.

-Aaron
 
aelgin said:
Is Birchwood Casey Super Blue just a wipe on cold application and let it dry? No baking or anything?
Click to expand...

Pretty much, you clean the blade with soap and water, then using a wool dobber wet it with the bluing. You let it sit for a minute or so and rinse with a little scrubbing with scotchbright or steel wool. Repeat. It takes 3 or 4 cycles to get a good even black. Hit it with a little oil and it looks great.
 
I've got a question I've been thinking about and you Mr. Justin Presson can probably answer it.

How do you get it to stay that black? I'll do 3 or 4, 3 minutes cycles through pcb and it ends up black....but the black rubs off very easily. If I immediatly stone wash it, the stone washing doesn't rub it off and it looks great, but as soon as I rinse it off and rub it, it wipes right off. How to you get the black to set?
 
Neutralize it right away with windex and then you can try going straight into a pot of boiling water with baking soda in it for 15 minutes or so. That will help lock the dark black color in.
 
This is how I do it and I learned this from Darrin Sanders(hope its ok to share) I let it sit in my etch for probably 30 min so it is good and black. Wash off in the sink rubbing the slim off and then hang it from a wire in a deep pot of boiling water with a couple tablespoons of trisodium phosphate in it for about 15 minutes, Darrin said that helps to set the etch.
 
I just tried this out with PCB for the first time tonight. Sanded to 400 grit. Cleaned with soap then rinsed and wiped with denatured alcohol. Soaked for about 30 minutes. When I pulled it out the blade portion was a nice solid dark black but when it got down to the handle area it sort of faded to a dull grey color. Any suggestions or ideas on what I may have done wrong?
 
My guess is that the handle maybe wasn't hardened as the blade...to have an uniform etching the microstructure of the steel should be uniform to begin with. If the hardening was done, maybe you had removed the thin decarb layer finishing the blade, and insisted less on the handle.
Of course i assume you didn't touch with your bare hands the handle after degreasing, before etching.
 
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