Amazing documentary from Sweden showcasing how they made iron from raw clay they harvest in a bog. This method is how they made raw materials for tools, weapons and export from the early iron age until the industrial revolution! The first step is to dig up clay rich in iron ore from a bog. The clay is left to dry in piles and then transported to a foundry nearby the bog. At the foundry the first step is the roast the raw material. This is to remove moisture and biological material. The temperature of the fire is around 500-600°C but not higher since the material should not melt yet. This shrinks the raw material to 50% of it's original mass, sometimes to a third of it's original mass. This process takes 2-4 hours. As this happens the men prepare the foundry. In a stone clad hole in the ground with an air vent at the bottom firewood is stacked. When this is lit on fire the men takes careful precautions to not allow it to burn up completely. After an hour the firewood is turned into charcoal used to turn the now refined iron ore into iron ingots. The roasted iron ore is placed into the bed of coal will sink slowly sink to the bottom of the pit as the coal burn with a temperature in-between 1200-1400°C, the men peak into the airhole at the foundry and can tell from the colour of the temperature is correct or if they need to adjust it. The bellows blows 350L of air into the foundry per turn and the entire process takes up to four hours. The lump of iron is still full of slag and byproduct. To remove this its beaten with a hammer on site. At a smiths workshop a smith continue to hammer our out the byproducts until it's refined enough for production! In the forests there are many traces of iron ore refinement. The foundry's can still be found in good condition even if they have not been in use for over 500 years and traces of slag and byproduct still litter the ground.