Brass helmets versus bronze helmets

[jkaler48]

It seems that brass wasn't common in roman use untill the 1st Century AD
(yes I don't use the politically correct CE and BCE) and therafter items were
often some form of Gunmetal (Copper tin zinc alloys). A search of the internet turns up articles with information on Roman alloy but they typically want $50.00 to read them. Does anyone have any actual test infomantion on
Roman bronze helmets?

[Quintius Clavus]

Do you have access to Bishop & Coulston's "Roman Military Equipment"? At the end they discusses metallurgy, including that of Roman copper alloy helmets, also comments about tests done, etc.

Quinton Johansen
Marcus Quintius Clavus, Optio Secundae Pili Prioris Legionis III Cyrenaicae

[jkaler48]

It seems that brass wasn't common in roman use untill the 1st Century AD
(yes I don't use the politically correct CE and BCE) and therafter items were
often some form of Gunmetal (Copper tin zinc alloys). A search of the internet turns up articles with information on Roman alloy but they typically want $50.00 to read them. Does anyone have any actual test infomantion on
Roman bronze helmets?

No but just ordered an updated version from Amazon.com will have it in few days. Thank you for the suggestion!

Here is the link to Amazon.com in case anyone else wants one.

[Gaius Decius Aquilius]

R.F. Tylecote, Metallurgy In Archaeology, 1962, edward Arnold Ltd. I think is the classic work.

The study is moslty limited to England, which would be normal given the general lack of available data outside Europe. Roman bronze seems to be first made by the inclusion of calamine oar which contains zinc. Zinc content varies from 1.5% to 36% with the average of about 18-20%. Some 1 to 2% lead content was not uncommon. Tin runs from 2% to 36 % with the majority of samples in the 3-9% range. Nicle is rarly present due primarily to copper oar sources. Casting brass has lead present and approximates modern "gun-metal" alloy. Wrought alloy seems to range arount 5% each of zinc and tin.
It seems the main difference between Early , Middle, and Late Bronze Age in alloy composition is the presence and quantities of arsnic and/or antimony. Toxicity produced strange behavior similar to a modern meeting of the city council or some such.

R. Izard

[Tarbicus]

Can you please use the URL function to insert very long URL's!? Just pasting these beasts in makes a thread impossible to read.

Modded myself

[Robert Vermaat]

Modded it including your shouting... :wink:

[jkaler48]

Casting brass has lead present and approximates modern "gun-metal" alloy. Wrought alloy seems to range around 5% each of zinc and tin.
R. Izard[/quote]

So should the brass helmets on the market really be made of "Gun-Metal"?

Modern Gunmetal has:
"The so-called 88–10–2 (copper-tin-zinc) alloy is the “government bronze,â€

[Gaius Decius Aquilius]

So should the brass helmets on the market really be made of "Gun-Metal"?

I doubt it, but... For all the 350 odd pages in Tylecote, I find no quick reference to any helmet or armor being tested. The term for Roman copper alloy, orichalcum, is not discussed. However, it is used for both helmets, things like hinges, and coinage, and may cover a multitude of compositions, some for specific purpose. Most items tested were common household goods, jewelry, and a few early weapons. The Roman period zinc stuff has a lot of variation in proportions so I don't think there is any hard and fast rule. What works, works. Local variation based on raw and recycled material availability would not be any surprise.

Most commercial bronze and brass alloy is proportioned to some modern casting or reposse technique. The so called "Ancient Bronze" is called such because it is formulated to take patination well, not to duplicate ancient composition. Sheet "red brass" has lead in it. This kinda, sorta, looks like some original pieces I have, except the originals seem to be a bit harder.

I have full scale casting equipment which I rarely use. (I can batch produce buckles, belt fittings, belt plates, etc. if I ever get motivated to do so.) I have been told that to make bronze/brass harder, put in a little broken glass. Whether this was known to the Roman world, I do not know.

R. Izard

[M. Demetrius]

Well, we can be pretty sure they had broken glass...