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Otto Karl




Location: Ulm, Germany
Joined: 05 Dec 2007

Posts: 15

PostPosted: Mon 25 Feb, 2008 2:37 pm    Post subject: About black damascus         Reply with quote

I was reading a lot about Japanese sabers on vacation [yeah, about folding steel and something more] and then I came to this page and saw that blade: how in the world do they made that odd looking black steel? Do anyone of you have a single clue?

The page is http://www.wkc-sports.com/Blackheartofdragond.html
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Dustin R. Reagan





Joined: 09 May 2006

Posts: 264

PostPosted: Mon 25 Feb, 2008 2:53 pm    Post subject: Re: About black damascus         Reply with quote

Otto Karl wrote:
I was reading a lot about Japanese sabers on vacation [yeah, about folding steel and something more] and then I came to this page and saw that blade: how in the world do they made that odd looking black steel? Do anyone of you have a single clue?

The page is http://www.wkc-sports.com/Blackheartofdragond.html


Steel, when heated above a certain temperature (and in the presence of oxygen, of course) oxidizes. This layer of oxides, if the steel reaches a certain temperature, is nearly always black/dark grey.

To make the steel look like most people think that steel looks (shiny), you must polish off this layer.

Black finishes can be obtained this way (bring the sword to final polish, then briefly heat and let oxides form again). Furthermore, you can coat the steel, after final polish, with all sorts of different compounds and heat up the steel...oil coating a blade and then heating it will get you a black finish like this...and is safer for the heattreatment of the blade. There are also modern day bluing chemicals that can be applied to steel cold.

I don't know which of these methods was used here, but i would bet it was a chemical treatment.
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Shayan G





Joined: 26 Sep 2006

Posts: 140

PostPosted: Mon 25 Feb, 2008 4:16 pm    Post subject:         Reply with quote

Would it be the same for real Damascus, not just pattern-welded? I saw this tulwar in the Victoria & Albert museum, the flash makes it look light but it was really almost black. It was gorgeous:


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VICTORIA & ALBERT 031.gif

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Dustin R. Reagan





Joined: 09 May 2006

Posts: 264

PostPosted: Mon 25 Feb, 2008 4:47 pm    Post subject:         Reply with quote

Shayan G wrote:
Would it be the same for real Damascus, not just pattern-welded? I saw this tulwar in the Victoria & Albert museum, the flash makes it look light but it was really almost black. It was gorgeous:


You can finish most any blade steel using the methods i described above. Over time, steel (of any sort) will slowly develop a controlled patina of surface oxides...old blades often have a darker patina to them than newly forged/polished steel. This may be why the tulwar you saw looked so dark (would have to see it to know for sure, though).

I guess the thing I should be pointing out is that, besides very slight variations in color/texture, the surface appearance of steel will be the same regardless of whether it's modern mono-steel, pattern welded steel or wootz/crucible steel. The differences you see, are mainly due to the many different polishing and etching techniques used to put the finished surface on blades.
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Brian Johnson




Location: Firth, Idaho
Joined: 02 Feb 2008

Posts: 9

PostPosted: Mon 25 Feb, 2008 9:31 pm    Post subject:         Reply with quote

Greetings, I am a custom knifemaker/swordmaker and am new to this forum. I hope I can be somewhat of a resource here. The black color on the damascus blade is likely to be just an etching technique. After damascus steel is forged and ground, it must be immersed in an acid solution (I use ferric chloride) that targets one of the steels present in the blade. The less acid resistant steel is eaten away to some degree and the other steel is left nearly as it was. This leaves the blade slightly textured. A black carbon deposit accumulates on the surface of the entire blade. After the acid etch, the blade is usually final polished to remove the carbon deposit from the high spots on the blade (the more resistant steel). This results in a nicely contrasting shiny pattern over a dull gray background. The blackened blade shown in the picture looks just like my blades do before I do a final polish.

p.s. by "damascus" I mean pattern welded. I have no experience with actual wootz type steel.

Unfortunately, those who continue to live by the sword will inevitably get shot by those who dont.
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Robin Palmer




Location: herne bay Kent UK
Joined: 21 Dec 2007

Posts: 138

PostPosted: Tue 26 Feb, 2008 9:40 am    Post subject:         Reply with quote

While I agree with Brian that is one method of bringing up the pattern in many cases the process of grinding and polishing will bring the same results. I suspect the V&A swords colour may also be caused by centurys of oiling which will darken the steel over time. Given its age I doubt the V&A will want to re polish it.

As to the black Katana my bets on gun chemical cheap and quick plus requiring no great degree of technical ability.
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Otto Karl




Location: Ulm, Germany
Joined: 05 Dec 2007

Posts: 15

PostPosted: Tue 26 Feb, 2008 2:11 pm    Post subject:         Reply with quote

Boys, a katana has to be polished an regrounden itīs whole life because non aleated steels tend to rust so much. It means that a cosmetic surface treatment is not desirable for such weapon; so, the steel is black itself. The question is now "Do you know some sort of black steel and itīs composition?" Because it is more probable this steel is that way.
And yes: I know carbon do tend to evaporate and accumulate on the surface when the steel is heated, but it woud be awful if the blade decolorates after polishing.
So... Anybody know a source of black steel and the way it is made?
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Shayan G





Joined: 26 Sep 2006

Posts: 140

PostPosted: Tue 26 Feb, 2008 2:27 pm    Post subject:         Reply with quote

Thank you Mr. Reagan, Mr. Johnson, and Mr. Palmer--those were helpful answers! I was wondering about that sword for the past two weeks since I visited the museum!

As an aside, Vince Evans has some black pattern-welded blades on his photostream. I'd reference his website but I don't know about bandwidth etiquette or copyright issues...a googling for "Vince Evans bladesmith" will suffice!
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Jared Smith




Location: Tennessee
Joined: 10 Feb 2005
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PostPosted: Tue 26 Feb, 2008 3:57 pm    Post subject:         Reply with quote

Brian Johnson wrote:
Greetings, I am a custom knifemaker/swordmaker and am new to this forum. I hope I can be somewhat of a resource here.


Brian, I am glad you have joined.
I hope you will start some posts on making pattern welded blades/ knifes. I am in the process of setting up a propane forge (Diamondback Knifemaker model.) Others here also are starting out and have similar interests. I intend to go straight towards pattern welding (no farrier interests, not particularly interested in generic blacksmithing.) I will not have the advantage of a trip hammer. Raw material tradeoffs, and how to hand fuller/ extrude the welded billet, etc. are of great interest to at least a few here.

Absence of evidence is not necessarily evidence of absence!
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Brian Johnson




Location: Firth, Idaho
Joined: 02 Feb 2008

Posts: 9

PostPosted: Wed 27 Feb, 2008 12:31 pm    Post subject:         Reply with quote

Otto, I have never seen a naturally black colored steel. If the color is not a surface treatment, then I am just as curious as you are.[/quote]
Unfortunately, those who continue to live by the sword will inevitably get shot by those who dont.
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Aloy Diaz




Location: Philippines
Joined: 05 Nov 2007

Posts: 2

PostPosted: Fri 29 Feb, 2008 1:49 pm    Post subject:         Reply with quote

That shiny black katana might just be chemically treated, looks like the finish in a Berretta 92f (brunitron finish or something). True black steel (if ever there is such a thing) is just steel that has a lot of impurities in it, this is the reason why some old Katana's and a lot of Philippine swords produced in antiquity are coloured black... The antique japanese katana had to be folded and refolded to hammer out the impurities (take out the slag) as the smelting process used in the past was inferior (there was always some slag left)... this is also why antique japanese swords have a wood patern (if you look at them closesly you will see grains on them, the thin black part that makes up the lines producing the wood grain is just plain slag that was never hammered out by the folding and refolding process)... same with the antique Philippine blades - the metal also had to be folded and refolded to get rid of the slag. Of course the Japanese were more sophisticated sword makers and such they were able to hammer out more of the slag and produce better blades... Philippine blades do tend to be darker (just more slag left in the metal) and a bit rougher..
Aloy Diaz
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Jon H.





Joined: 22 Dec 2007

Posts: 27

PostPosted: Sun 02 Mar, 2008 3:33 am    Post subject: Re: About black damascus         Reply with quote

Dustin R. Reagan wrote:
Steel, when heated above a certain temperature (and in the presence of oxygen, of course) oxidizes. This layer of oxides, if the steel reaches a certain temperature, is nearly always black/dark grey.

To make the steel look like most people think that steel looks (shiny), you must polish off this layer.

Black finishes can be obtained this way (bring the sword to final polish, then briefly heat and let oxides form again). Furthermore, you can coat the steel, after final polish, with all sorts of different compounds and heat up the steel...oil coating a blade and then heating it will get you a black finish like this...and is safer for the heattreatment of the blade. There are also modern day bluing chemicals that can be applied to steel cold.

I don't know which of these methods was used here, but i would bet it was a chemical treatment.
Do any of these treatments, especially the reapplication of heat to obtain the blackened finish, affect the blade in any other way besides aesthetics? Namely, do you risk the blade becoming more brittle or less flexible?
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Adam Bodorics
Industry Professional




Joined: 15 Apr 2005

Posts: 115

PostPosted: Sun 02 Mar, 2008 4:42 am    Post subject:         Reply with quote

While I'm not an expert on steels, I've never found a steel which is black by material. I searched, as I prefer black over any else color, but I failed. Even wootz, which can sometimes be VERY black is shiny if grinded.
BTW, AFAIK oxides are not a bad thing if they are covering the entire surface - they'll stop most other oxides appearing. About regrinding... I don't think reoxidating would be a hard task for someone who made it before.
...
Jon H.: While I never tried blackening treated steel, I frequently oil blackened my mild steel armours. Even if the oil reached only a reddish state, the plate softened a bit, and making the oil layer black needed a higher temperature. About heat discolorization: if the heat used is under the recristallization heat, it wouldn't change steel properties in theory. But I'm not sure if cca 300 °C is enough for blackening.
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Brian Johnson




Location: Firth, Idaho
Joined: 02 Feb 2008

Posts: 9

PostPosted: Sun 02 Mar, 2008 1:31 pm    Post subject:         Reply with quote

300 degrees Celsius / 570 degrees Farenheit is not hot enough to blacken steel without the use of oxidizing chemicals. This is near the upper end of the tempering scale for most commonly used sword alloys. Any higher temperature can severely diminish blade performance. Typically, steel will take on a dark grey color if heated to around 1000 degrees Farenheit or above, but rich black oxides cant effectively be formed without the use of some kind of chemical aid. The following website has a handy chart that illustrates the colors that can be attained within the tempering range of steel: http://www.anvilfire.com/index.php?bodyName=/...colors.htm
Unfortunately, those who continue to live by the sword will inevitably get shot by those who dont.
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Dustin R. Reagan





Joined: 09 May 2006

Posts: 264

PostPosted: Sun 02 Mar, 2008 2:09 pm    Post subject:         Reply with quote

Otto Karl wrote:
Boys, a katana has to be polished an regrounden itīs whole life because non aleated steels tend to rust so much. It means that a cosmetic surface treatment is not desirable for such weapon; so, the steel is black itself. The question is now "Do you know some sort of black steel and itīs composition?" Because it is more probable this steel is that way.
And yes: I know carbon do tend to evaporate and accumulate on the surface when the steel is heated, but it woud be awful if the blade decolorates after polishing.
So... Anybody know a source of black steel and the way it is made?



Otto, I am well aware of the polishing necessary during the life a real nihonto...I don't see what that has to do with this katana-shaped sword...

The steel is definitely *not* black, itself.

Such a material does not exist. Though, If you want to believe in fairy-tales, it's not my duty to persuade you otherwise...

Also, carbon does *not* evaporate and accumulate on the surface of steel when it is heated...the iron/steel on the surface oxidizes. If the steel gets heated above a certain temperature in the presence of oxygen, the carbon itself will burn *out* of the surface of the steel.

Dustin
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Glen A Cleeton




Location: Nipmuc USA
Joined: 21 Aug 2003

Posts: 1,801

PostPosted: Sun 02 Mar, 2008 3:35 pm    Post subject:         Reply with quote

Is it just possible that the original poster's reference was alluding to iron bearing black sand (magnatite)? From which tamahagane is smelted.

Just a thought

GC

Never mind, yes an etch.
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James R.Fox




Location: Youngstowm,Ohio
Joined: 29 Feb 2008

Posts: 253

PostPosted: Sun 02 Mar, 2008 5:34 pm    Post subject:         Reply with quote

Guys-read up on George Cameron Stone Arms and Armour etc. O.K. he was wrong about wootz steel, but none of the smelting sites in India and China had been found, let alone cleared by experienced metallurgists when he wrote his book..So,he only recognized folded steel He had, and cites,with a photograph,a Persian dagger that was yellow and blsck,divided in a straight line down the middle of the blade.I was going to look up the page number for you,but then I thought that everybody needs to read George on a regular basis or they will never be civilized.It is in one of his sections on Persian blade smithing.He says the type of steel with impurities that made it yellow or black was produced in Khorasan, and he had seen it before, and it is produced by impurities in the ore.While I agree the the medieval persians were the greatest blade smiths ever on the planet or any other, the fact the he does not recognize that they are using wootz steel, not folded steel makes me suspect some of his statements about metallurgy.I realize the is gross heresy, and will turn myself in to the thought police in the morning. Laughing Out Loud
Ja68ms
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Otto Karl




Location: Ulm, Germany
Joined: 05 Dec 2007

Posts: 15

PostPosted: Mon 03 Mar, 2008 3:13 pm    Post subject:         Reply with quote

Dustin R. Reagan wrote:
Otto Karl wrote:
Boys, a katana has to be polished an regrounden itīs whole life because non aleated steels tend to rust so much. It means that a cosmetic surface treatment is not desirable for such weapon; so, the steel is black itself. The question is now "Do you know some sort of black steel and itīs composition?" Because it is more probable this steel is that way.
And yes: I know carbon do tend to evaporate and accumulate on the surface when the steel is heated, but it woud be awful if the blade decolorates after polishing.
So... Anybody know a source of black steel and the way it is made?



Otto, I am well aware of the polishing necessary during the life a real nihonto...I don't see what that has to do with this katana-shaped sword...

The steel is definitely *not* black, itself.

Such a material does not exist. Though, If you want to believe in fairy-tales, it's not my duty to persuade you otherwise...

Also, carbon does *not* evaporate and accumulate on the surface of steel when it is heated...the iron/steel on the surface oxidizes. If the steel gets heated above a certain temperature in the presence of oxygen, the carbon itself will burn *out* of the surface of the steel.

Dustin


Ok. I give up and will ask the source for more information. I thought it was not even possible to produce a black steel because steel is a metal and has an electron cloud that belongs to all the lattice itself, giving it the optic characteristic of reflection at the wavelengths of the visible spectrum. By the way, I was wondering if an etching or a bluing process could ruin the hardening of the edge.
But the carbon does evaporate from the lattice when it is heated, that is what a physics professor told me in college, because I asked him if it was the carbon being attacked by the atmosphere as a result of the thermionic emission from the heating. My analysis was fallacious: when the carbon is attacked by the atmospheric oxygen, carbon oxides are produced and is not possible to find a black carbon layer on the surface, as it happens. But the process itself is somewhat weird (A solid evaporating from another one? Weird!), so we are not able to think about it. Is something like passing though a wall without being forced to go to a hospital. Really weird!
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James R.Fox




Location: Youngstowm,Ohio
Joined: 29 Feb 2008

Posts: 253

PostPosted: Mon 03 Mar, 2008 4:39 pm    Post subject:         Reply with quote

By the way I looked at the Blackheart page, that is after-coated steel. You can get it from Windlass Steelcrafts through MRL and other outlets as well. As far as I Know, steel colored black at forging is as George Cameron Stone said-it's made from impure ores which he says can be obtained in Khorasan Persia (Iran)
Ja68ms
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Dustin R. Reagan





Joined: 09 May 2006

Posts: 264

PostPosted: Mon 03 Mar, 2008 6:35 pm    Post subject:         Reply with quote

James R.Fox wrote:
As far as I Know, steel colored black at forging is as George Cameron Stone said-it's made from impure ores which he says can be obtained in Khorasan Persia (Iran)


Very cool, I take back what I said then. my mistake...apparently it *is* possible for steel itself to appear black. Has anyone successfully reproduced this black "impure" steel?
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