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Post by durinnmcfurren on Jul 4, 2021 23:29:37 GMT
I found an interesting article, and the pictures show something that looks really quite good. Has anyone tried doing this themselves? I hope no one cares that this links to a different forum, if that is a problem then please delete this!
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Post by durinnmcfurren on Jul 5, 2021 0:31:18 GMT
Do you mean just patinas in general or one exactly like the OP in that thread? Both but mostly the black patina in that thread
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Post by aldarith on Jul 5, 2021 2:55:31 GMT
That isn't a patina, that's gunblue. You can do that with a cold bluing process such as birchwood casey. Alternatively you can do a forced antique patina very easily with vinegar, and totally bonkers patina with vinegar+salt. The best patina of all comes from a dip in hot vineger and salt though, IMO. *Edit* I read the thread - I guess it IS a patina, it just looks like gunblue. So yes, I have done this. It's basically the dip I described. It isn't a hard patina though, it can be worn off with use so you really need to build it up with multiple applications. Gunblue would be faster though
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Post by durinnmcfurren on Jul 5, 2021 4:38:25 GMT
Right, I'm just wondering if it really comes out that dark.
Gunblue is also an option, but I'm not sure cold blue gives a patina, more of a covering.
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Post by aldarith on Jul 5, 2021 4:49:04 GMT
It only becomes that dark after repeat treatments. Maybe ACV creates a darker patina than regular white, but in my experience about 50% of each treatment is easily wiped away or worn off so you need to do multiple applications in order to build a truly thick and uniform patina.
It will also look dark when wet and the next day will have lightened slightly, so you have to account for that when deciding when to stop.
I haven't done that exact treatment but it sound right to me.
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Post by AndiTheBarvarian on Jul 5, 2021 5:09:52 GMT
I tried it with three swords, with two to enhance pattern welding and one to get a black stormbringer blade. After several treatments the blade got a good looking, uniform dark grey to black patina. But it wasn't stable. Even when wiping the blade with a oiled cloth some of the patina faded and parts became a brighter grey. This treatment is ok to darken a bright blade a little bit to grey or to enhance pattern welding but for a dark grey or black it isn't stable enough.
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Post by neuronic on Jul 5, 2021 8:14:16 GMT
Any patina is a mild form of acidic etch, basically. Or oxidization (and reduction), if you will.
FeCl3 (ferric chloride) is an easy enough way to etch a dark patina into carbon steels.
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Post by Ari L. on Jul 5, 2021 20:17:31 GMT
I haven’t tried this specific method, however yes it should work, but as others say it won’t be very durable.
There are three important Iron Oxides. •Iron(II)Oxide or FeO.
•Iron(III)Oxide or Fe2O3 which is composed of two Iron(II)Oxides plus an additional Oxygen, bumping its oxidation level from II to III. This is good ol flakey red-rust.
•Iron(II,III)Oxide or Fe3O4 which is composed of one Iron(II)Oxide and one Iron(III)Oxide. Also known as Magnetite or ‘black rust/patina’ this bonds stronger to the steel than red rust, appearing black.
The goal then is to make sure you are forming these mixed oxides on the surface while also controlling the growth of any unwanted Iron(III)Oxide. Hot blueing salt baths do just this, but are hot and dangerous. Most methods that try to replicate hot blueing salt baths but in lesser, albeit safer, conditions will produce more unwanted oxide inclusions and achieve a black look but with a surface that’s only loosely connected to the steel underneath. When working with these lesser conditions, slow and steady is the way to go and long soaks in mildly acidic baths will do better than short applications of extreme acid.
(Of note, store bought “Cold blue” is a slightly different process and will produce a different looking but more durable black).
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Post by durinnmcfurren on Jul 6, 2021 2:00:13 GMT
I haven’t tried this specific method, however yes it should work, but as others say it won’t be very durable. There are three important Iron Oxides. •Iron(II)Oxide or FeO. (Of note, store bought “Cold blue” is a slightly different process and will produce a different looking but more durable black). First, I really appreciate the chemistry! For whatever reason, I suck at chemistry (even though I'm a mathematician professionally and also have a physics background). But I find it very interesting. So I am glad to know a little more about why the patinas differ (I always wondered why the usual rust is nasty red-brown but you can also produce a blackish patina).
Second, yeah, I knew that cold blue solutions are somewhat different. In fact I was under the impression they impart a layer of something else on top of the steel? Rather than simply oxidizing it in a controlled way? But again, I suck at chemistry, so I may be wrong.
(PS somehow in college I tested out of chemistry, which to this day perplexes me because _I don't know jack about chemistry_)
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Post by durinnmcfurren on Jul 14, 2021 21:16:22 GMT
Ok so follow up. I'm experimenting with this, and I have two questions.
1. Can the apple cider vinegar lose its acidity over time, and thus its ability to cause this chemical reaction?
2. How long should I leave it on before wiping it off? The instructions on that link said 3-5 minutes.
I ask this because with the (rather old) apple cider vinegar that I tried, I only got a marginal amount of darkening. More like to a medium or light grey than a dark grey/black color. But maybe it's because it was old, and maybe I didn't leave it on long enough. I only tried two applications, as well, figuring I would go back to the drawing board before trying again...
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Post by tera on Jul 14, 2021 23:54:17 GMT
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Post by pullrich on Oct 23, 2021 17:38:35 GMT
Plum browning gives a nice looking and hardy patina.
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Post by squalembrato on Oct 23, 2021 20:55:13 GMT
Two "organic" methods that give a grey patina to carbon steel blades: 1. Cut a grapefruit or orange and rub it on the blade and let it sit for awhile, 2. just pee on the blade and let it sit.
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