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Well, bronze is not necessarily made of tin, other metals can also be alloyed with copper to the same effect. Museums use the term "copper alloy" precisely because the composition of historical bronzes and brasses - what would have been collectively called "latten" back then - were highly variable and more or less interchangeable.

Paul Mortimer wrote:
Dan -- VWs and Rolls Royces? Well really!

Honestly, if I drove, I'd rather have a Golf than a Silver Ghost. :)
I never considered the possibility of pure copper rivets. I just assumed that it was a copper alloy of some kind. I was asking why would they use copper alloy and not iron? The galvanic reaction between the two metals would cause corrosion a lot faster. There is no increase in strength. They would increase the cost of the item. The only reasonable explanation seems to be related to decorative purposes.
Paul Mortimer wrote:
As for not 'seeing the difference between mechanically flattened overlaps on Indian rings compared to no similarly flattened overlap in western or eastern mail... then please continue to enjoy your commission" -- I tell you again, that I have seen quite a few examples of period mail in England, Sweden and Denmark - and unless you get up really close, you don't really notice any difference.

You don't have to get close. I can distinguish between Indian links and proper links even on TV. The Indian links are pretty distinctive. In some cases it would be better to simply go with butted links because it is a lot harder to tell that the links don't actually have any rivets and they don't have the wacky overlapped section to give them away.
Paul Mortimer wrote:
Kel - the original science report by W A Oddy and A E A Werner (Bruce-Mitford 1978 page 20) on examining a surviving rivet, says, "The spot was found to be mainly copper, containing lesser quantities of iron, lead, silver, silicon magnesium and calcium. These elements are mostly derived from the soil and the rivets were probably made of copper containing small amounts of lead and silver." So perhaps not bronze?

As for not 'seeing the difference between mechanically flattened overlaps on Indian rings compared to no similarly flattened overlap in western or eastern mail... then please continue to enjoy your commission" -- I tell you again, that I have seen quite a few examples of period mail in England, Sweden and Denmark - and unless you get up really close, you don't really notice any difference.


Thanks for the report link. I don't study early medieval artifacts much so it is enlightening.

Also, sorry to put you on the defensive, it was not my intention. As Mikko commented, if these suit your purposes by all means enjoy them. I meant nothing more than that. The fact that Dan and I are such nitpickers shouldn't diminish your enjoyment of your commission. :)
Dan, I am sure that you could spot the difference at 1,000 metres, perhaps 2,000!

Kel, thank you for your concern, but there is no need to worry. When you post anything on a forum there is always the possibility that there will be criticism and that is fair enough. It's good if it can be couched in a supporting manner and it can be galling if it comes from someone who rarely, if ever, attempts anything themselves --- obviously not the case here, though.

I was aware, too, that there are limitations with my new coat, however, I am very pleased with it and for all the purposes that I will be using it for in the near future, it is very good. It still is a close enough resemblance to surviving examples of mail from my period and a little earlier for me, and many others, to be satisfied. Perhaps one day I will change it for a completely custom made coat. As I explained previously I have attempted to do that before on two occasions, but did not get the response that I had hoped. I also had a lot more funding available then than I do now.

Reconstruction always, or nearly always, involves some compromises, (at least for the 6th and 7th centuries) as long as you are aware of them and don't try to hoodwink anyone, I feel that is perfectly acceptable. Perhaps the nearest that I have come to owning a perfect reproduction is the recreation of the Sutton Hoo Stone (at least the stone part) as that was made using the same stone as the original and period tools and methods. Because it isn't weapon related, I have never posted it on myArmoury. However, we learnt so much from the processes that we wrote a book about it.

I had hoped, too, that there may be a bit more knowledge around about the use of copper/bronze rivets in mail and why they were sometimes used. Perhaps there may be more ideas out there?
http://www.britishmuseum.org/research/collect...p;partId=1

Quote:
Mail fragment composed of alternate rows of theta-shaped, solid links and smaller, riveted links of round-section wire with circular rivets of copper alloy. At one side is a border of riveted links, all of brass with brass rivets.


Brass rivets in the brass edging rings is also not as common, as most European mail seems to use iron rivets in the latten edges. Here's an example of iron rivets in latten (brass) rings from a German shirt of mail in the Metropolitan Museum of Art.
http://images.metmuseum.org/CRDImages/aa/orig...TS1D1b.JPG

An example in the collection of Wade Allen, possibly of Persian origin.
http://www.allenantiques.com/M-7.html
Quote:
Small piece of Mail. Each ring stamped with parallel lines. Wedge rivets of brass.


I don't think Wade's example actually has wedge rivets, but more of a rectangular or oval shape like those in this Syrian or Iranian shirt in the Met, also with copper-alloy (brass?) rivets in the iron rings and apparent iron rivets in the brass rings at the neck!.
http://images.metmuseum.org/CRDImages/aa/original/DP147152.jpg
http://images.metmuseum.org/CRDImages/aa/original/DP147153.jpg

Gordon Frye's initial post in this thread indicates copper rivets in some New World Spanish mail, but no one has confirmed this or the provenience of the Museum's holding.
http://www.myArmoury.com/talk/viewtopic.php?p=29088
Jack S. Williams wrote:
By the way, years ago Art Woodward told me that he could always recognize chain mail that had been made during this period in Mexico, as the rivet used were copper or brass, instead of the traditional iron or steel. I remember seeing a shirt of this type once at the Heard Museum, in Phoenix.


Last edited by Mart Shearer on Fri 07 Mar, 2014 5:04 am; edited 1 time in total
Mart - thank you for the links (no pun intended). I can't get the BM one to work but will try another way in soon.

Do you know the dates of any of the samples? The Met one with the lines on the links is intriguing -- it looks like solid and riveted but there is something going on -- perhaps it is the tailoring? The Allen sample resembles it quite closely.
Wow.

It is interesting, too, that they are using copper/brass/bronze rivets in the New World at a such a late date. Perhaps there are advantages in using non-ferrous rivets?

Paul
Sutton Hoo mail
With regard to the flattened section of the links in Paul's new mail shirt, there is an interesting drawing of the links from Gammertingen on page 50 of the recently published 'Das Frankische Heer der Merowingerzeit' that appear to show very similar link construction with the flattened section.

regards
Dave
Paul Mortimer wrote:
Mart - thank you for the links (no pun intended). I can't get the BM one to work but will try another way in soon.

Do you know the dates of any of the samples? The Met one with the lines on the links is intriguing -- it looks like solid and riveted but there is something going on -- perhaps it is the tailoring? The Allen sample resembles it quite closely.
Wow.

It is interesting, too, that they are using copper/brass/bronze rivets in the New World at a such a late date. Perhaps there are advantages in using non-ferrous rivets?

Paul


The Met example is assigned "circa 1500". It is indeed of demi-riveted construction, with alternating rows of solid and riveted rings. Repair rings of round section are also present.
http://www.metmuseum.org/collections/search-t...&img=1

I find it peculiar that they would use copper-alloy rivets in the iron rings and iron rivets in the copper-alloy rings, all in the same garment.
Mart Shearer wrote:
Paul Mortimer wrote:
Mart - thank you for the links (no pun intended). I can't get the BM one to work but will try another way in soon.

Do you know the dates of any of the samples? The Met one with the lines on the links is intriguing -- it looks like solid and riveted but there is something going on -- perhaps it is the tailoring? The Allen sample resembles it quite closely.
Wow.

It is interesting, too, that they are using copper/brass/bronze rivets in the New World at a such a late date. Perhaps there are advantages in using non-ferrous rivets?

Paul


The Met example is assigned "circa 1500". It is indeed of demi-riveted construction, with alternating rows of solid and riveted rings. Repair rings of round section are also present.
http://www.metmuseum.org/collections/search-t...&img=1

I find it peculiar that they would use copper-alloy rivets in the iron rings and iron rivets in the copper-alloy rings, all in the same garment.
It don't think its peculiar at all if it is primarily for decorative purposes. As Mr. Mortimer's recent aquisition demonstrates, the contrast is quite striking, and I can see why it would appeal to a warrior looking to add a little flash and demonstrate his means.
There are a number of late 12th and early 13th century references in various chansons of "saffroned" hauberks and byrnies. There has been debate over whether this refers to latten mail, latten borders on mail, or some other sort of latten patterns woven into the mail. It could be that these copper-alloy rivets fit the bill.

From the Hervis de Metz (Garin le Loherain), l. XLV
http://books.google.com/books?id=JYSupMhje0sC...mp;f=false
Quote:
Bone est la coife dou blanc hauberc safré,



http://books.google.com/books?id=tn9WAAAAcAAJ...mp;f=false
Quote:
Frappa Olivier sur son hauberl safrei.
Solz las gonelas an brunhas safradas.
Roman de Gerard de Rossillon, fol. 32.

Sous les gonelles ont cuirasses safrées.
Maius haubiers à pans saffrés.
Roman du Renart, t.IV, p.359.

Nel pot garir escu n'hauberc safré.
Roman de Garin, Carpentier, t.111 col. 675
Dan Howard wrote:
I never considered the possibility of pure copper rivets. I just assumed that it was a copper alloy of some kind. I was asking why would they use copper alloy and not iron? The galvanic reaction between the two metals would cause corrosion a lot faster. There is no increase in strength. They would increase the cost of the item. The only reasonable explanation seems to be related to decorative purposes.


Some copper alloys will give a large increase in strength - some brasses have about double the tensile strength of mild steel or wrought iron.

If these rivets were close to pure copper, with a little silver, we can look at the numbers for an alloy of copper with 0.05% silver:
Tensile Strength 221-462 MPa
Yield Strength 69-365 MPa (probably at the high end of this for rivets, which will be work-hardened)

which, compared with wrought iron,
Tensile strength 234-372 MPa
Yield strength 159-221 MPa

So, on average, expect improvement in strength. At least, the decorativeness shouldn't hurt the effectiveness of the armour. Improvement in strength is greater than the increase in weight due to the greater density of copper, so if thickness is reduced to keep weight the same, still stronger.

For those who might like a little explanation of the numbers.
Tensile strength is the stress (force divided by cross-sectional area), in tension (i.e., stretching), required to snap the material; yield strength is that required to permanently stretch it. A low yield strength + high tensile strength material can make very good armour, since the deformation of the armour will absorb a lot of energy. But then it will need repair. High Yield strength + high tensile strength gives an elastic and strong armour. Assuming it isn't brittle. The numbers are ranges, rather than single values, since the actual test results will vary. For wrought iron, it'll depend on chemical composition and (especially) slag content. For the copper, it'll depend on chemical composition, work-hardening, and tempering/annealing.

(Numbers from AZoM, http://www.azom.com/article.aspx?ArticleID=9555 and http://www.azom.com/article.aspx?ArticleID=6329 )
The Tofta coif's riveted rings are almost pure iron, while the rivets are iron with a high phosphorus content. Even though they are both ferrous, the ring and rivet are made from two types of wire. I don't think enough metallurgical study of the rivet alone has been done compared to the ring to reach any definitive conclusions, but it's possible the material for the rivet was chosen for hardness, like other nails.

Alan Williams, notes decarburization around the rivet in several rings. Perhaps heat was applied to the rivet area after the rivet was set? Has Williams ever done analysis of the rivet alone?
http://www.themailresearchsociety.erikds.com/..._6.pdf[/i]
Thank you Mart -- I suppose there is a consistency in using iron rivets with the copper alloy rings.
As for the Tofta coif -- the use of high phosphoric iron would help to prevent corrosion in the rivets, which, because they are smaller maybe more vulnerable. That could be for decorative effect, too, as the rivets would stay bright while the iron in the links would be much duller - and as you point out phosphoric iron is usually harder than wrought iron. I suspect, too, that you are right, too, in that not enough work has been done on the metals of the links and rivets -- perhaps it was normal practice to use different materials for different functions. There is certainly quite a lot of evidence that by the first millennium there was quite a sophisticated trade in various irons and that many smiths understood the qualities needed for specific tasks.

Timo, it is very interesting that copper may actually perform better than iron. Certainly a great deal of food for thought. Thank you.

Paul
Copper alloy rivets could be stronger than iron but that doesn't matter much with mail. When the links fail it is almost never because of the rivet. The link itself usually tears.
Dan Howard wrote:
Copper alloy rivets could be stronger than iron but that doesn't matter much with mail. When the links fail it is almost never because of the rivet. The link itself usually tears.


But what is this information based on actually, a few modern tests and a few existing damaged examples. The people who made, used and repaired the originals may have known something we do not currently have the ability to see.
Eric - you are, of course, correct. I shall take this further when I next see Dr Brian Gilmour of the Oxford University Archaeology Research Lab. We have been having discussions the use of iron alloys during the post-Roman period, but he knows a great deal about other metals in archaeological finds, too. Hopefully, I will meet be seeing him next month.

Paul
Paul Mortimer wrote:
Eric - you are, of course, correct. I shall take this further when I next see Dr Brian Gilmour of the Oxford University Archaeology Research Lab. We have been having discussions the use of iron alloys during the post-Roman period, but he knows a great deal about other metals in archaeological finds, too. Hopefully, I will meet be seeing him next month.

Paul


Paul, please post any thing you may find out.
I will. Brian has a great deal of experience in looking at finds from many different cultures and time periods, I am sure that he will have some clues as to why they used non-ferrous rivets. I saw him last month, but we were focussed on iron and I never thought to ask him about the mail.
Paul Mortimer wrote:
Mart - thank you for the links (no pun intended). I can't get the BM one to work but will try another way in soon.

There was a typo in the URL. Here's a corrected link: http://www.britishmuseum.org/research/collect...p;partId=1
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