Forging Bronze Age Armour

[David Scott]

Ancient Origins has published an article and accompanying video, Forging Forgotten Ancient Greek Armor which gives some insights into bronze-smithing in Glorantha. While some of the  equipment used is clearly modern, it's a great look into ancient Greek armour:

Article: https://www.ancient-origins.net/videos/ancient-greek-armor-0019053

Dimitrios Katsikis on Instagram: https://www.instagram.com/hellenicarmors/

His exhibition in Athens: https://www.hellenicarmors.gr/en/

Video on Youtube: (Keep an eye out for the Air Rune reference...)

 

[JRE]

Amazing work, but I assume there are some differences with ancient practices. He seems to use modern Naval Bronze (which is actually brass), mainly used now because it is more resistant to corrosion and gives a great look with good mechanical properties. That is the easy to find metallurgic bronze nowadays. It can be worked quite fast by hot forging, as the forging temperature (when the metal is softened but still solid) is quite low compared to the melting temperature. It can be worked down to dark red (<500ºC) before needing reheating.

Ancient bronze, and what I assume is used in Glorantha, with 10% Tin, has a higher hot forging temperature, which means shorter work periods and continuous placing in the forge, which also means a high fuel consumption. So rather than hot forging some people, according to records, did cold forging. You do not heat it intermittently as in hot forging, you heat it for quite a long period at a lower temperature till it is all softened, let it cool down without stress and then you shape and hammer till it is too rigid to work more. That also hardens the metal (work hardening) which is quite useful for weapons and armour, though it may increase brittleness. Many weapons and small armor pieces would be cast in a mould, a technique he does not show, and then cold forged to profit of the work hardening of the bronze and avoid the brittleness of the casting process.  Tin enrichment also increases the hardness, but that probably was used only in weapon points and edges, as it becomes too brittle for useful armor.

The armor looks beautiful, however, and it reminds us that bronze was still used in armor long into the Iron age, as it looks good, is often more resistant than iron, it is easier to work and repair and much more resistant to corrosion. It was much more expensive, so it was a sign of riches as well.

This is a text I had started about Gloranthan metalworking techniques. I am not a metalworker, but working with furnaces, ceramics and metals, you always learn a few things.

Working the metals in Glorantha.

Cold working.

The most primitive option to work a metal object is to just shape it or work it cold. That is actually workable with soft pliable metals, which are easy to deform: lead, gold and copper, and it fits with the Trolls dislike of open flames and fire in general. Copper is the hardest of the three but also the one that can give you some workable tools, apart from clubs, that will benefit from the heaviness of both lead and gold. Silver can be roughly worked this way, but it is not easy to get nice shapes.

Lead was not widely used in Earth because it does not exist in metal form and smelting is difficult. Gold and copper were mostly used for jewelry, though copper had other uses, as stone or fire hardened wood is almost as good as copper and better than the others, except in blunt heavy implements.

Casting

Melt the metal, pour it into a sand or clay mould, let it cool, and you have a nice metal piece shaped as you want. Unless you have access to metal moulds (with a much higher melting temperature than your molten metal, so no bronze moulds for bronze) details will be poor and you will need to do some finishing work. Cast metals are usually soft and brittle, so you will need some annealing and work hardening to get useful tools.

 Cold forging

In this case the metal is heated to soften it (annealing) and then it is worked cold or almost cold till it hardens. Depending on the work, it may be repeated several times.

This works with almost all soft metals and allows silver to be worked almost as easily as copper.

The window of opportunity when the metal is soft but cold and what temperature you need to anneal depends on the metal. Bronze can be worked this way, but it is very time consuming as you need to heat the metal to dull red for some time, quench it, and then it work hardens very fast, so normally you have only a minute or two to shape it. So if you have enough fuel you use hot forging.

 Hot Forging

Hard metals need to be softened before they can be wrought into shape. That is most likely the only way most Gloranthans interact with iron, as it will not melt with the furnaces available, specially the wrought iron or steel that the dwarves sell out, and I am sure it is deliberate.

Forging is a matter of shaping the rough form coming from a sand mould, or repairing or changing the shape of an existing piece of metal, as well as making sure there are no cracks or defects that will make the metal fail. As such it requires high temperature but not extreme.

The table shows typical forging, annealing and melting temperatures, which shows how hot your forge or furnace has to be. I have also added the color it would normally correspond to, as that will be the main guideline a Gloranthan smith will have. Annealing temperatures will be a lower but close to the forging temperature, and you need the metal to stay certain time to increase the ductility that allows the cold working.

 

Metal	Forging Temp. (ºC)	Melting Temp. (ºC)	Preferred method
Lead	-	320	Cold working, casting
Aluminum	300-400	660 (dark red)	Casting and finishing
Copper	900 forging (cherry red) 500 annealing (black red)	1080 (orange)	Cold working, cold forging
Gold	-	1060 (orange)	Cold working
Tin	-	232	Casting
Bronze	600-700 forging (dark red to dull cherry red) 500 annealing	950 (cherry red)	Casting and hot forging. Some cold forging
Silver	500 annealing	960 (cherry red)	Cold working, cold forging
Iron	1200 (yellow)	1500 (white)	Hot forging, annealing and tempering.

 

 

[JRE]

Some additional notes.

Aluminium is a special case, as it can be cast at normal temperatures or just underwater, casting quickilver (liquid, but heavy so it will always sink to the bottom) and then turning it into aluminium while in the mould. Some finishing and it is done.

In the Earth's Bronze Age, Smelters were a prestigious job, though risky as well, as they were the ones with the secret knowledge of how to purify and mix the different ores to get a good metal. In Glorantha smelting is unknown, except by the dwarves, as people do not process ores but just take metal from the ground. That is maybe why they do not do much alloying at all, as that was the smelters initial job, to compensate for the presence of other metals in the ores, specially arsenic and zinc. In Glorantha the main alloy is adding the mostly useless tin to the plentiful copper to get the useful bronze. I am sure the dwarves do make special alloys, such as making a lead bronze to lower the melting point, or adding some aluminium to make it lighter. I am pretty sure the Brass in the Carmanian Brass mountains is a copper-lead alloy that the dwarves make as a balance to the copper-tin  bronze.. In most cases, metals contain traces of copper and possibly tin or lead, depending from what period of the God War can it be traced, the Lesser or the Greater Darkness, which is why "pure" runic metals are usually only available from actual god bone portions, as all others were alloyed in former times to avoid the magic blocking.

With the exception of iron and seldom used tin, Gloranthan metals are analogues of metals that do not corrode easily, or at all. That means that a piece of metal from the first age is probably still around and in use, though possibly in the meantime it will have been a horseshoe, a sword, a bell, a buckle, a cloak clasp and now it is a hoe blade. Recycling to the limit. Iron, IMG, still rusts, and the dwarves consider that a feature. As seen in the working temperatures, iron will be very hard to forge compared to the other metals, requiring special forced air forges with high quality charcoal, or magic. In Glorantha I assume it will be mostly magic, and otherwise an iron piece will be very difficult to shape or melt, another part of the mystique of iron.

IMG Fire elementals are good aids for metalworking, but not a perfect solution, as they have a gradient of temperatures, with the hotter at the core, so you need tools long enough to reach inside, and probably expose you to flesh burning temperatures to work, so some kind of fire protection is a must. As you can damage an elemental with any weapon, unless you are toasting marshmallows, any real heating will require insertion inside the elemental, and I make such a manipulation cause 1 HP of damage to the elemental. So fire elementals cannot be used as help indefinitely.

A small elemental could melt lead or tin, or heat objects for annealing up to 500ºC. They are the most used, as they are easier to control and a normal tong may be enough to reach the core. 

A medium elemental can help with hot forging bronze, but you will need extra long tongs. It could melt aluminium, but turning it to quicksilver is easier. The core would soften bronze items, so it will require skill to use one.

A large elemental core is enough to melt bronze and other metals except iron. Any metallurgic use of such elementals will need iron tools. But you can probably work all other metals easily. Melting is not an instantaneous process, so a bronze spear will still damage it, but it is likely the shaft will burn and if all metal, it will soften and become misshapen.

[mfbrandi]

29 minutes ago, JRE said:

As you can damage an elemental with any weapon, [and] any real heating will require insertion inside the elemental, … I make such a manipulation cause 1 HP of damage to the elemental. So fire elementals cannot be used as help indefinitely.

“I test the sharpness of my swords on slaves, but as they tend to bleed, they cannot be used as help indefinitely.”

And you still get the same salamander with every summoning? Back in the day (RQ2), elementals had 1d6 INT and that put one in six elementals in the low average IQ range (80, according to the back of my envelope), but even if smart elementals are no longer as bright as one in eleven humans, I bet they can still build up quite some resentment. They tried to unionise, but on the picket line, their strike placards soon turned to ash.

Is this really how we want to treat the staff at Gustbran Incorporated? Say instead that salamander working hours are limited by the fatigue of focusing their heat, the EU Working Time Directive, or common decency? Or that only hissable villains would use salamanders in a forge, it being so bad for their health?

[metcalph]

19 minutes ago, mfbrandi said:

And you still get the same salamander with every summoning? Back in the day (RQ2), elementals had 1d6 INT and that put one in six elementals in the low average IQ range (80, according to the back of my envelope), but even if smart elementals are no longer as bright as one in eleven humans, I bet they can still build up quite some resentment. They tried to unionise, but on the picket line, their strike placards soon turned to ash.

Is this really how we want to treat the staff at Gustbran Incorporated? Say instead that salamander working hours are limited by the fatigue of focusing their heat, the EU Working Time Directive, or common decency? Or that only hissable villains would use salamanders in a forge, it being so bad for their health?

Well, if the Salamanders were working for the cult of Vrang 2Jhomang, it's probable they would have been the brains of the operation.

[mfbrandi]

1 hour ago, metcalph said:

Vrang 2Jhomang

I’ll give you Jho if we can do the Goddess Switch on Orlanth and Panash.

[David Scott]

2 hours ago, mfbrandi said:

And you still get the same salamander with every summoning?

If you use summon (type) elemental, yes, per RQG 343, until it dies. RQG elementals have no INT.

Edited August 10, 2023 by David Scott