The descriptions of the preparation for the battle of Moytura by the various skilled craftsmen lead to intriguing speculation about the skills and technologies of the builders and weapon-makers within the story.
For example, Section 122, which describes the daily restoration of the Dé Danann weapons, creates an entertaining and “high-octane action” picture of the activity within the forge. Goibniu beats spearheads and sword-blades with three strokes, throwing them to Luchta, the carpenter, who forms the shafts in three chippings, fitting the heads to the shafts with fine finish on the third chipping. Luchta, then, lobs them to Creidne, the brazier, who rivets the heads in place with three strokes, throwing them into the air to achieve their permanent joining. Clearly, this is a spectacular, almost super-hero demonstration of skill with a delightful comedic element, but it does illustrate the stages and demarcations of early weapon-crafting.
The word grés, used to describe Goibniu’s three strokes, Isolde translates as “technique” rather than “stroke” or “blow” (see The Forge and The Well). So Goibniu, therefore, forms the spear heads with three techniques, grésai
A passage from Fergus Kelly’s Early Irish Farming (page 487) may throw light on this process. The law texts say that a proper axe should be manufactured in three heatings, the donngorad, “red heat”; the bángorad, “white heat” and the gored foberta, “heat of tempering”. Fobairt literally means “bringing under”, perhaps connected with the cooling of the spear by immersion in water. Could this be a description of the three techniques?
The ‘proper axe’ was clearly an item of some value. The legal commentary of Bretha Comaithcesa states that an axe that has only been through two heatings is worth no more than one scruple.
There is another process mentioned in section 124 of our text. A woman refered to as Crón is seen grinding weapons. Now her name implies a blood-red colour. Might she be tempering iron in blood, or ornamenting with red enamel? There are indications suggesting that red was an important colour in connection with forging iron. This may just be the obvious link between fire and forging and the blood produced by the weapons’ use, but there are other indications. The Romans thought that the best iron was made with the urine of a red-headed boy, and Balor disguised himself as a red-headed boy when he stole the Glas Gabann from Goibniu’s forge.
Now, I am no expert on early bronze or iron smelting, but these sections of the story sent me searching. This isn’t the place for a history of metallurgy in Ireland, but I offer a few gleanings I have found particularly interesting.
Goibniu’s Forge ~ A local tradition
In Ireland, as elsewhere, copper was known before iron. According to tradition, the mines of Slieve-an-ierin (the ‘mountain of iron’), east of Lough Allen in the 
County of Leitrim, just down the road from here, were worked by Goibniu, the smith. Iron was mined on this hill right up to the 18th century. The well-known, “Ha’penny Bridge” in Dublin was made from this iron.
When did the Iron Age begin? ~ An intriguing find
This iron spearhead is of a kind familiar enough from the Ireland of 500 CE. Andy Halpin of the National Museum of Ireland says that it “wouldn’t be out of place in the early medieval period”. The problem is that recent carbon-dating of the remains of its wooden shaft suggests that it may be more than 1,000 years older. If this is so, it explodes a myth about how the Iron Age came to Ireland.
The long-held belief was that the use of iron in Ireland was a result of the invasion of the Celts. These people are associated with the development of ironworking in Europe north of the Alps, and with a culture named after the Austrian town of Hallstatt. Greek writers refer to the existence of ‘Keltoi’ in central Europe in the sixth century BCE. The Hallstatt people seem to have been responsible for the westward spread of ironworking. It seemed logical that the appearance of iron in Ireland must be evidence of the arrival of these Celts. No one doubts that the influence of these central Europeans is evident in Irish artefacts from the sixth century BCE onwards. But the process was not one in which the Bronze Age suddenly ended and there is no reason why this date has to be regarded as wrong. It’s the combination of this early date and its superb quality that makes this spear so startling. “We are beginning,” says Halpin, “to get other evidence for ironworking technology at an earlier date than we thought. The idea that ironworking was happening here in maybe 600 or 700 BCE wouldn’t really be disputed any more. But the idea that they were producing something as nice as this at that period suggests not only that iron was being worked here, but also that it was being worked by very competent smiths much earlier than we think. Those smiths were not invading ‘Celts’. They were part of the same culture that was producing the dazzling gold and bronze objects we have already seen.
from http://www.100objects.ie/portfolio-items/iron-spear-head/
An Iron Age Collection
This article, quoted from the notes describing the Iron Age collection at the National Museum in Dublin, also confirms that dating for the coming of iron to Ireland has been re-considered. I include the notes as being generally descriptive of the range of Iron age assembleges.
Recent radiocarbon dates from sites excavated in the Irish midlands suggest that knowledge of ironworking may have been known from as early as the eighth Century BCE. At Kinnegad 2, Co. Westmeath, charcoal found associated with iron slag and pottery of Late Bronze Age type, yielded a date range of 810 – 420 BCE. At Rossan 6, also in Co. Westmeath, charcoal associated with iron slag yielded a date range of 820 – 780 BCE. The transition to the widespread use of iron, in preference to bronze, appears to have happened slowly and over a long period, and it was not until around the third Century BCE that a distinctive Iron Age society, clearly recognisable in the archaeological record, emerged. What gives the period its distinctive character is the widespread use of ornament to decorate objects using an art style that was developed first in central Europe by Celtic peoples. Known as the La Tène style, the art occurs on early objects, such as two imported gold collars found in a bog at Ardnaglug, Co. Roscommon that were probably made in the Rhineland in the third Century BCE.
Much of the Iron Age collection was uncovered during river drainage schemes and the cutting of peat bogs during the 19th Century and some important finds were acquired without their provenances being recorded. The collection is rich in high quality bronze objects that were found in hoards, together with some highly important hoards of gold artefacts. The native metalwork of the period is distinctive and contains types of objects that appear to be exclusively Irish, such as large ornamental bronze discs of unknown function and elaborate Y-shaped pendants that appear to have been used to lead horses in procession. It appears that the hoard material was deposited mainly as votive offerings placed in bogs, lakes, rivers and along the seashore, and the types of objects represented are seldom, if ever, found in settlement or burial contexts. Usually, the hoarded artefacts fall into a number of clear categories including personal ornaments, weapons and tools, horse furniture and harnesses, and feasting equipment.
Personal ornaments include pins, fibulae, beads, bracelets and neck ornaments. Simple collars of twisted gold strips are known but there is also the sumptuous gold collar found on the seashore at Broighter, Co. Derry. This find was associated with imported neck ornaments of Roman workmanship as well as an exquisite gold model of a boat, complete with mast and fittings, and a model cauldron.
Feasting equipment comprises metal and wooden vessels, including cauldrons, bowls, cups, platters and large wooden troughs. Horse furniture and harnesses include the Y-shaped pendants mentioned earlier, which have been found in association with pairs of bridle bits. Wooden yokes found in bogs and the remains of wheeled vehicles are also included in the collections. Weapons include swords, scabbards, chapes, spearheads and spearbutts. Among the organic finds from bogs are votive deposits of butter, a leather shield and items of clothing fashioned from wool, leather and hide. There are also a number of mummified bodies, referred to as bog bodies, which are the remains of persons who were killed as part of a sacrificial ritual during the Iron Age. There is also a small amount of carved stone including quern-stones and stone heads of which the Corleck Head is a well-known masterpiece.
The collection also contains imported Roman material including objects recovered from archaeological excavations and stray finds. Among the exceptional finds is a hoard of silver ingots and chopped up fine silver tableware from Balline, Co. Limerick. Other finds include coins and jewellery excavated on cult sites at Freestone Hill, Co. Kilkenny and Newgrange, Co. Meath. A number of objects imported from Roman Britain, including weapons and personal items, were discovered in an Iron Age cemetery on Lambay Island, Co. Dublin.
Quoted from http://www.museum.ie/en/collection/iron-age.aspx
Experimental Archaeology
I found Neil Burridge’s descriptions of bronze sword-making particularly interesting.
http://www.bronze-age-craft.com/swordcasting.htm
He says, ”I am a specialist in reproducing bronze age artifacts using authentic materials and methods. Throughout the year I run a series of practical workshops at different venues, covering many aspects of prehistoric materials and the technology to work them. They are very ‘hands on’, and are designed for people with no previous experience. They offer you the chance to follow in the footsteps of ancient craftsmen and learn some of their skills to open a window onto the past.”
Go to http://www.bronze-age-craft.com/ for further information