Smelting

At 5 o'clock we started with slowly heating the furnace and in three hours stabilized temperature at 1100 °C and pressure of air 5 mm w.c. Then we began with putting ore and charcoal (1,2 kg /2 kg of each) at every 20 min. After 6th charge we began with first tapping of slag (together 6 times). After 14th charge, 5 hours of smelting we presumed that the furnace is full therefore we removed the shaft, the upper part of furnace. We hadn't a slight figure what to do and tried to dig up the bloom with big tongs but unsuccessfully. We had to cool the furnace. Next day we tried again . The bloom was hardly connected to the inner brick. We had to remove it to get the bloom out of the furnace. The bloom' s weight was 8 kg and had thick outside layer of slag which was easilly to hammer off. Inside there was the smooth and solid round 5 kg block - the bloom we had never seen before.

 

Smithing eksponati-taljenje-železa

The smithing hearth was charged also with charcoal and driven with ventilator at higher pressure of air. We heated the piece of bloom for 30 min. The slag was melting and running out of iron. That was the moment to weld iron together. On this principle many different methods of refining of bloom was invented and used. This step to get solid billet of iron is most difficult and one of the critical moment of ancient iron process.

When the billet is homogeneous then it is possible secondary smithing to iron bar and final product.