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New Kopis From Dioskouri
#46
Quote:Last October i met with archeologists in Vergina for a two-days workshop. An archeologist had brought photos taken with an electronic microscope from the sections of greeks swords of the 5th and 6th century. These swords were definately folded many times with the addition of carbon, but this is not pattern welded, and even if some patterns were scarcely visible, this was not intended. It was the result of trying to harden the material by alternating soft and harder layers, since they couldn't add carbon to their alloy. This is already important news in itself. It is wrong to claim pattern welding in greek swords however.
Yup, that is exactly what one would suspect. It is the same way as most ("mono-") steel items were made in antiquity, from kitchen knives to frying pans.
Our reco of the Sisak blade has this feature, too:


[attachment=2642]fertig5.jpg[/attachment]


Also, as far as the sources go, these blades, even the pattern welded ones, were in antiquity not treated with acid to make the patterns more visible. This is probably a modern feature to "show off", although it would have been well within the capability of ancient craftsmen, of course (vinegar, e.g.)


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Christian K.

No reconstruendum => No reconstruction.

Ut desint vires, tamen est laudanda voluntas.

LEGIO XIII GEMINA

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#47
I was told there was some discussion of my work on this forum, so I joined.

well where to begin....

Damascus, pattern-welding, laminated; these are all related or the same really. Its only a matter of making it look one way or the other. All were used in antiquity to add carbon into the iron matrix. Examples of this time of forging surface even before the Greeks. There was some strong debate amongst Metallurgists (not Archeologists) as to whether cast and wrought iron were being used to create these steels. However from a molecular perspective this wouldn't yield a useable steel as cast and wrought iron precipitate too much carbon. This creates a layer on top of the ferrite which disallows its being hammer fused sufficiently. In fact the process of making cast iron and wrought iron means carbonizing the iron beyond the percentage needed for quality steel. If the Greeks could make cast or wrought iron, they could and did make proper steel. The laminated layers seen in Greeks swords is not purely and cast iron layered up, it would fall apart like Tiramisu, for lack of a better analogy. Beating pure iron together would fuse it without layers, beating cast and wrought iron together creates unstable layers, beating layers of properly carbonized steel creates fused but distinct laminations as seen in artifact weaponry. Its not an argument, its physics.

While Damascus as we have it today, can be viewed as inauthentic it is only because its made in a very controlled way today. The damascus patterns I've seen in artifacts is very blotchy and irregular. No one did it for looks back then and they didn't, I'm sure, etch it like they do today. Pattern-welding is more or less, simply giving laminated steel a twist while continuing to flatten and re-flatten the billet. Same process but it creates a different pattern. more linear in appearance than Damascus. Mostly because Damascus is usually made with rods rather than folding a flat billet. While I would love to only make properly bloomed and carbonized iron to use for swords and thus everyone can have perfectly authentic swords....the cost per sword would be about $2500-$3000. The process was simple and the best way in antiquity to make this steel. Today however we have a vast resource of mills and manufacture that produce much better steel at a fraction of that cost.

I would love to stay as authentic as possible but just sometimes the cost is beyond most everyone, even me! I am simply trying to provide better alternatives for reenactors than has been available. Nothing from India, or Pakistan is worth anything IMHO.

I have posted in the marketplace for 4 swords I am completing in the coming days. I am making these out of 1095 steel. Its as authentic as you can get for the small pricetag. Its a good steel, tough and will hold a decent edge.

This has been a very long post so I won't address the helmets here unless someone is actually interested. Wink

eharisto


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Michael
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#48
I wish this thread had started just 2 weeks earlier...before I ordered the first Manning.... :roll:

I am very intersted in what you have to say about the Corinthians Michael.
I was trying to find information on this 10 years ago, which led me into reenacting, as I was getting nowhere with the limited internet facilities available to me and lack of access to knowledgable metalurgists!
Visne partem mei capere? Comminus agamus! * Me semper rogo, Quid faceret Iulius Caesar? * Confidence is a good thing! Overconfidence is too much of a good thing.
[b]Legio XIIII GMV. (Q. Magivs)RMRS Remember Atuatuca! Vengence will be ours!
Titus Flavius Germanus
Batavian Coh I
Byron Angel
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#49
Well I would never suggest you cancel your Manning order (cancel) Smile 

After all who can't wait for 18 more months anyway, it'll go by quick. Smile

Regarding the helmets, this could be a forum by itself! Let me start by setting some ground rules here as there is a tremendous amount of variation and a long time span covered by these helmets.

***The helmets I am making are of one type and have definitive characteristics and time frame in which they appear. They are the zenith of this helmet type, so my discussion as to their construction and metallurgy will be limited to this type***

All helmets show a wide variance both in their alloy and construction techniques so I hope I don't get mobbed and stoned to death here, as what I am giving up here is by no means inclusive of all artifact helmets. There are many types, and even helmets within a single group can display very different characteristics. They are only classed by their form and not so much by construction or metal type. Classification of the helmets into groups is generally the responsibility of Archaeologists, which I have extensively studied this for 30 years. The helmet's construction, the techniques used and alloy content is the responsibility of conservationists and metallurgical specialists; those are the people I am working with. Over several weeks the information I received about helmets and this type specifically has been fascinating and was either unpublished due to a perceived lack of public interest or was intentionally withheld. I'm not sure which, as I didn't ask whether this was super-secret information or not. So for the time being I'll discuss what I know I can divulge without pissing off any highly placed museum people in the process.

Ok, let's begin......... Smile


A. Routinely we have been told that Corinthian helmets were beaten and formed out a single sheet of bronze.

True and False

While this is true for the earliest style up until about 530 BCE, the Greeks started to change the bronze they were using for their helmets making them stronger but also less and less malleable by hammer. Additionally, changes in the helmet's form, started to preclude the simple forming techniques of hammer-and-stake that had always been used. Myros and Lotus helmets are an example of simple hammer forming and these helmets were sometimes as thin as 1mm! But advances in weapons technology quickly showed these thinner helmets in the weaker bronze alloy and were of little protective value as warfare evolved.

B. Corinthian helmets were bronze, similar to Phosphor bronze today.

False

Greeks used a specific alloy of bronze for their helmets that is unique and not used for any other armor or weapons. We know this today because advances in technology have allowed us to now see and determine specific elements, trace elements and ratios of elements in these alloys. By the time the helmet type I am making had evolved, the alloy had reached its strongest. With a roughly translated (and I mean roughly, as bronze isn't measured by Rockwell) a Rockwell hardness of 57! That's as strong as the average steel sword! Incredible for a copper alloy!

C. Nasal pieces and cheek plates on Corinthians were brazed on.

False

No helmets in any period, of any type display any welding! With repairs in antiquity and restoration of some helmets in the 19th century being the exception along with a few curious anomalies. 

D. Corinthians were restrictive of vision and hearing.

Probably no more so than any other helmet type. While helmets produced today tend to be on the 'bucket' side and the increased distance from the actual eye opening or ocular, to the wearer's eye can and will greatly diminish his visual field. In antiquity, helmets fit very closely with little distance between the eye and ocular opening. Likewise today's overly long helmets tend to cover down below the ear. Actual helmets either flare out or cover only to the jawline meaning that, while a little diminished, hearing would not have been greatly decreased.

The project involving these helmets is intended to give researchers a newly made helmet of the type and alloy used in the actual artifacts. In a sense, what I am doing is making the first real Corinthian helmet in some 2,000 years, even down to the metallurgy. The artifact helmets are too fragile and too precious to be smashed and the data gleaned from such destruction would be useless as in their present state, as they are nothing like they were originally.

The ability to the test this helmet for flexion, torsion and shear forces, as well as penetrative resistance, will be the first time anyone has been able to determine the true physical capabilities of these helmets. There was a reason the ancient Greeks devoted so much engineering and time to create such a helmet and a reason why the bronze used for them was special and used solely for helmets. The researchers as well as myself are extremely anxious to answer all these questions which have been beyond our reach until now.

After much correspondence, it seems they have no issue with allowing these helmets to be commercially sold as well as used in their research. Now it's a question of price!

I am happy to, and prefer to make these helmets out of the 'special recipe' bronze; however; the cost for a helmet made this way is looking to be somewhere between $1800-$2000. While some may easily afford this or save up for it, many cannot afford that. As mentioned earlier in this thread, is phosphor bronze is more accurate than silicon bronze?

Yes and no. While silicon bronze has almost no tin in it, it also does not have phosphor or much lead either. The silicon replaces the tin and lead and creates a stronger matrix within the copper. So while phosphor is a truer bronze, it's physical characteristics are less like the original helmet alloy than silicon is. So silicon isn't as accurate for research, but for color and physical strength, it is closer. If you are solely interested in a completely accurate and REAL Corinthian helmet, then start saving your pennies. If a very accurate and beautiful looking helmet which is strong and won't dent is mostly your interest, and the accuracy of the metallurgy is not as important, then a cheaper silicon bronze helmet is a better deal. Offering this helmet (if there is any interest) in silicon would price out somewhere around $800-$1000 - a much more affordable price point.

Once I am fully set up to make these, I'd anticipate the turn around from order to delivery would be between 3 weeks to at most 2 months. I can't (and won't) take orders that have you wait in limbo. It's rude.

*working on greaves too, just to throw that out there.
Michael
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#50
Thank you! I feel you have confirmed whatI have always felt!
Visne partem mei capere? Comminus agamus! * Me semper rogo, Quid faceret Iulius Caesar? * Confidence is a good thing! Overconfidence is too much of a good thing.
[b]Legio XIIII GMV. (Q. Magivs)RMRS Remember Atuatuca! Vengence will be ours!
Titus Flavius Germanus
Batavian Coh I
Byron Angel
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#51
Michael -- Am I understanding you correctly that you will make one more affordable set of helmets in silicon bronze and one set in your "special blend" bronze? And that you consider silicone bronze the best commercially available bronze for making a corinthian helmet?

If that is the case, my first question is then: Why would you not use 10/90 tin bronze? I know that this blend is not easily (or at all) available in big enough plates, but if you intend to cast a blank that shouldn't be a problem. As far as I understand it tin bronze is close enough to historical alloys -- while it is also suitable to forge it hot. So my second question is: Have you tried forging silicone bronze hot? Perhaps you intend to cast the blank so close to the final result that you don't intend to use heat.
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#52
Well it's not really a matter of silicone bronze (Si) being the best or most accurate, but it is the least expensive and most workable commercial bronze available. I have investigated and worked with a lot of bronze alloys and all work slightly differently.

Phosphor bronze is closer but the inclusion of many other alloying elements in this and all commercial bronzes make them unsuitable for a true reproduction. It is simple to say a 90/10 bronze but in the metals market that isn't cheap; the higher the tin content the higher the price. Additionally any commercial ingots of 90/10 bronze always includes elements of lead, zinc, iron and other elements. So my choice was to buy very expensive metals to make these helmets, custom mix the actual alloy used, or choose a commonly available and least expensive alloy to use. As I have made lots of items which always end up being unsold because they are too expensive for this reenactment market to afford I decided that the least expensive option is what I should explore.

Lots of threads on here with people arguing authenticity and fine points of what was really done, yet few are really willing to pay what that costs. A Silicon bronze helmet is going to price out around $1000 USD and that is not including my labor! That's simply the cost of metal and forming. The clean up and polishing ends up being free because this market won't buy a helmet more expensive than this. The brinell hardness would be about 65, the 'real' alloy or historical alloy hardness is 108! However it has to be custom made for me and the increased costs are significant. The historically correct version will be somewhere around $2000. If people are really willing to pay for the real one I'd love to make nothing but those, but I actually expect to make very few of either. The cheaper, poorly made import helmets are hard to beat for price or availability.
Michael
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#53
Thanks for your prompt response. So what I gather is that you would prefer 10/90 tin bronze also for your commercially available helmets if it was more affordable? Your effort is truly laudable and inspiring, I just want to ask a couple of more questions to better understand where you are heading with this.

I saw this statement on your website: "The original museum helmets are largely epoxy bandages holding them together as they have lost much of their density and are more like foil than bronze, weighing between 3-5lbs. on average. However a new or 'live' helmet would have all of the bronze's original density. There is no difference between an ancient bronze alloy and a modern one, being exactly the same elements involved. The estimated weight of these helmets as new and finished should fall between 6-8lbs. most likely but it will be hard to estimate at this time." (http://www.dioskouri.com/Helmets.php)

The weight you are aiming for -- together with you previous comment that: "A Silicon bronze helmet is going to price out around $1000 USD and that is not including my labor! That's simply the cost of metal and forming. The clean up and polishing ends up [..]" -- suggests to me that you intend to cast helmet blanks with the lost wax method only aided by the force of gravitation. And that you will end up with blanks that are basically the finished net shape that requires little hammer work. Is this the direction you are taking?

If so, my main concern is that you, like you say, will have to put down such copious amounts that you won't break even, and that the helmets will be too heavy and, as you also indicate, too soft.

I have been thinking about these problems and done quite a few experiments, clay originals, and moulds, for quite a few days each year over the past six years. My conclusion so far is that for me it would be best to cast a blank that looks almost like an Apulo Corinthian, without any undercuts, and then hammer raise the last part of it to harden and make the metal more dense. Or to cast a thick, flat helmet blank and use assisted hammering on the inside and then raise it from the outside. In either case its possible to use more cost-efficient casting methods like sand casting. And it would be possible to get a lighter helmet without wasting too much bronze to grinding.

But maybe this discussion is more suitable in a thread of its own as it might not be too interesting for others in this thread.
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#54
Well I'm not 'aiming' for any particular weight really. I have to aim for the thicknesses in the helmet, the weight will end up being whatever these helmets actually weighed. In that respect, ancient or modern bronze is identical, that's what I was referring to. As to 'softness', Brinell 65 isn't soft per se, I was merely pointing out the difference between silicon and the old alloy. But I have to say this that the original recipe with its secret sauce is not amongst modern bronze alloys. While it is super hard this limits it use in industry or art for that matter. This is causing me to have to make it up special which is not a cheap endeavor.

Forming the helmet, like was done in antiquity, involves numerous processes. No two helmets are exactly identical but hammering the helmet for density and hardening the bronze in this manner is a common misunderstanding. Iron hardens this way, Bronze doesn't have the same structure. If you hammer bronze it becomes thinner and starts to become brittle, you have to alleviate that stress through annealing. Hammering bronze is a gentle affair done with the goal of only shaping not hardening. Early period helmets are as thin as 1mm but this is not due to thinning by hammer, the sheet used starts that thin. The helmet is then raised and constantly annealed to avoid hardening. Naturally early helmets were of a shape that was far easier to raise out of sheet as there is no undercuts or great changes in angles or circumferences. As warfare changed, the helmets had to also change. They become more complex with parabolic curvatures and angles that served the aesthetic and structural needs of the helmets. The alloy used also changes over time and is not the same bronze they initially used. By the Persian War period their bronze helmets were stronger (yes I said stronger) than steel. This fact alone probably warrants its own thread. This was a necessity as the helmets were routinely struck with steel weapons, so the paper thin hammer formed helmets of the 7th-6th century were useless as defense. A different methodology, metallurgy and technique is going on with the helmets here that is really unknown to anyone outside of the research personnel amassing this information. It is fascinating but it's forcing this reproduction into whole different directions than any currently available helmet made. I am attempting just to have a much more affordable helmet available to the market. One that has all the correct looks without being so super expensive in its materials.
Michael
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#55
I started a new thread on the helmet topic: http://www.romanarmytalk.com/rat.html?fu...&id=307998
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