"blackening" stainless - any recipies?

BossDog

BossDog

KnifeDogs.com & USAknifemaker.com Owner
Staff member
Looking to get a decent technique to darken/blacken stainless.

Getting non-stainless to darken is easy. Getting stainless to darken and have at least some wear resistance is proving to be less easy.

I've dipped in ferric chloride and muriatic. Both will give the blade a light gray. I've also tried bead blasting and dipping. A little better results this way.

If I can, I'm get some time today I'll be testing 2 parts hydrogen peroxide to 1 part muriatic acid today. What I expect to get is a decent dark blade from it but it hopefully doesn't mostly wipe off - which is what happens with most of this on stainless.

Now I've also heard that boiling the blades after etching help set the etch so it holds up and wears better. This is pretty commonly done when gun bluing so it kind of makes sense to try it also.
 
How long did you leave it in FC?
This is a little necker in Aeb-l I left in FC for 40 min then tumbled.
a2c739c712b45c43e80790892503fee0.jpg

Its not black but darkened quite a bit.
 
Justin Presson said:
How long did you leave it in FC?
This is a little necker in Aeb-l I left in FC for 40 min then tumbled.
a2c739c712b45c43e80790892503fee0.jpg

Its not black but darkened quite a bit.
Click to expand...

That is a great finish. I'll have to leave some in longer to try that.
 
It may be the type of stainless. I saw pictures of ATS-34 done in muriatic, where the blade was jet black. I have yet to try this blackening thing yet. Perhaps 100% ?
Frank
 
Bought the Caswell stainless blackening kit and thought would give a report. It comes with a bottle of blackener and a bottle of clear sealer. It applies a lot like cold blue gel, and works even faster. You have to follow the directions :what!: clean off excess with water and applying the sealer. (I discover if clean off with WD40 it will take off too much black) The sealer is optional but I used it as I think it helps protect the finish some.
Here is the test subject, an ATS34 tactical recently completed. Overall, it is a bit trickier than cold blue to use but does make a nice look if work with it some. Will see how it holds up after a kydex sheath is made and do some testing.

 
The Caswell stainless blackener works well. Follow the directions and give it a quick sandblast before dunking and it will give you a good dark color. Glass Bead blasting didn't work well. It took AO blasting to give it enough tooth to get a good bite.
 
Yea after doing one with the kit I can see where sandblasting prep would be better for bite and flatter sheen. I've got some AO on hand so will try another that way- thanks for the tip.
 
That's an interesting question that manufacturers of the M1 Grarand struggled with for years. Most of the rifle was steel that was parkerized but the gas tubes which hung under the barrel were stainless steel and would not accept parkerizing. Many formulas were tried to "blacken" the stainless. Eventually sodium dichromate was chosen as the most durable according to the Fulton Armory (See image below). But, the process doesn't appear to be amenable to the home workshop!

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Hi

O.K., I'm only a hobby knife maker, don't have a forge and haven't made a knife by stock removal either. I have blackened an arm load of Green River knives and high carbon steel blades. Given the ease of blackening high carbon steel, why do you want to blacken stainless steel? Although I'm almost certainly succeeding, I'm not TRYING to be a jerk, but isn't blackening stainless a little like having your gold metal bronzed?

Does stainless, especially after you try to stain it, wear THAT much better?

Thanks
 
For looks, Sir, for looks, without rusting and a certain type of steel for the blade that's wanted.
Frank
 
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Thanks, I wasn't actually TRYING to be a SmIart@$$. I've made and use quite a few Russel Green River kitchen knives and you have to keep them oiled or they get a bit of service rust.

Thanks again.
 
I figured it was a remark to get a reply. There are many in this forum as well as me who will use materials to "decorate" with. Certainly, then it's not always the actual practical results that are of primary concern. There is room for all of us here !
Frank
 
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