The first task was to build a kiln based on archaeological evidence – the 'footprint' left by the intense heat needed to melt iron. The team knew that these early kilns were averaging 30cm diameter and (in Iceland) were built of turf and stone. Over a three-day period, turf, lava blocks and clay from hot springs was gathered and the kiln began to take shape.
Project leader Martin Clark from Grampus Heritage in the UK explains what it's all about:
These days, we're incredibly wasteful and throw such a lot of things in the bin – including metal! Our common ancestors from the Medieval period knew the true value of metal because they worked incredibly hard for several days to produce just a few kilos. Iron was so precious that the poorest people had hardly any.
Up until the industrial revolution such kilns would have been a common site, dotted around the northern landscape. Using local iron rich soil and charcoal, the experiment began with fire, a constant draft to give plenty of oxygen and layers of iron soil and charcoal fed in from the top of the kiln's 90 cm high chimney.
Five hours later, the 'slag' was released from the kiln base like a mini-lava flow from nearby volcano 'Hekla'. Then the kiln yielded a mucky mass of iron, charcoal and cinders – called a 'bloom'. Our ancestors would then have beaten this with hammers, continually re-heating it and shaping it until the impurities were taken out. Afterwards, the bloom was divided between Icelander Guðjón Stefán Kristinsson and UK blacksmith David Watson who will create something memorable with it.