Segmentata hinges - is \'red brass\' ok?

[Flavius Promotus]

Gents,

our group wants to produce a number of Newstead segmentata cuirasses. We already have got the iron plates, but we are still not sure which material to take for the huge lobate hinges.
According to Mike Bishop's 'Lorica Segmentata' (p. 77), the brass fittings of segmentatae consisted of orichalcum, a copper alloy with a copper content of 80-85 % and a zinc content of 15-20 %.
He also writes that those modern alloys which most closely resembled this material were 'low brass' (CA240) and 'red brass' (CA230).

We now have found a company in Suebia which produce CuZn15 red brass sheets (= 85% copper, 15% zinc) with a thickness of 0,5 mm (more or less the thickness required for the lobate hinges of our Newsteads). According to one guy in this company, this alloy is relatively soft and flexible, but doesn't break as easily as the usual CuZn37 brass.

Now I would like to ask those among us who have already reconstructed and tested segmentata cuirasses: do you regard CuZn15 red brass as appropriate? Have you had any difficulties with hinges made of this material? What have been your experiences?

Thanks a lot in advance!

[LUCIUS ALFENUS AVITIANUS]

Zinc gives hardness to copper. So a high proportion of zinc gives a harder brass. If it's harder, then are less flexible.

The brasses what i have used are high zinc contents, so there are quite breakable. Generally, high zinc proportions are used today because are more easy to give form (with rollers, extruded, etc...)

If roman ones are made of an similar proportions alloy, what's the problem? All the troubles that have the roman will be made in yours, so it's interesting in order to do some experimental archeology.

What colour are that alloy? Yellowish?

[Doc]

Florian,

I am having my plumata made from Red Brass. Once you work harden it, it is not so soft.

Also the color of C230 Red brass is like gold, not the door knob yellow brass C260 is.

Matt Lukes is also making my manica out of C230 and it is turning out quite well.

So yea, if you have a source use it. It is flexible enough and has excellnet qualities for cold working. Once you harden it some, it will be excellent in appearence and function.

Also it is accurate since the elemental composition has been found concretely.

Paolo

[Magnus]

Unless someone has a portable testing kit with them at events, I'm sure no one is going to test the zinc content of the brass on your segmentatas... 8)

[Hibernicus]

And the "red brass", especially if you work harden it, stands up very well in SCA combat, by way of showing that it's tough enough!

[richsc]

Once you work harden it, it is not so soft.

The answer to that is to anneal it before it gets brittle, then work it again. You can do this cycle quite a lot until the brass gets to the point that it cracks. I've worked with both red brass and yellow.

no one is going to test the zinc content

After annealing you can't easily tell the difference

[Flavius Promotus]

Once you work harden it, it is not so soft.

Thanks everybody, but how exactly do you harden brass sheets? I guess this question will make the experts squeal in pain, but most members of our group are academics = we have an advantage when it comes to research, but we need technical expertise now and then :wink:

Is work hardening done by heating the brass, or by hammering it?

[jvrjenivs]

Is work hardening done by heating the brass, or by hammering it?

By hammering it you will hardening it, because you get so called dislocations, on moleculair scale. When you heat it again those dislocations will be re-aranged into a perfect ideal stacking and your metal is soft again.

[Flavius Promotus]

Thank you

Reminds me of 'If I had a hammer...'