Hi, this is Wayne again with a topic “Primitive Technology: Wood Ash Insulated Furnace”.
At the brick hut, The old brick furnace, Dismantling the brick furnace Digging a pit 50 cm in diameter and 12.5 cm deep Making mud, Plastering walls of pit Measuring pit 50 cm, Making a tuyere ( air pipe ) for furnace Making fire with fire sticks Fire in Pit and drying tuyere Dry pit Starting the inner wall of the furnace 25 cm in diameter, Installing the tuyere Building the furnace up above pit height Starting the outer wall of furnace at the edge of the pit, Inner and outer walls, Increasing height of walls, Finished furnace Walls 12.5cm below ground 37.5 cm above ground 50 cm tall overall Fire drying, inner furnace walls Punching temporary air holes in outer furnace walls for drying, fire Drying outer walls. Furnace is completely dry now, and the holes are plugged up At the brick making hut A batch of bricks is being fired, The ash from the fire will be used to insulate the furnace Ash is poured into the space between the inner and outer walls of the Furnace More ash was needed, so a fire was made, Ash was scooped in with a spatula because it was still hot. Meanwhile, iron bacteria was collected from the creek as an ore for the furnace to smelt. Another fire was made to roast the ore, The roasted ore. The ore is covered with a pan to stop dirt getting in and contaminating it.
The left over ash is collected for the furnace Finished furnace, Filling the base of the furnace with wood. The smelting set up 1 hour preheat with wood. Being insulated. The preheat should take less time than normal Filling the furnace with charcoal ( 9 double handfuls or approximately 1.5 kg ) 2 single handfuls or about 200g of ore, 3 double handfuls of charcoal 2 single.
Handfuls of ore, 10 charges of ore were added in total in 1hour 30 minutes ( it took longer than it should, because the blower broke and needed fixing part way through ) Damage to the blower housing Slag/iron mass. It was still hot the next day Charcoal in the slag Cast iron prills in the slag, Crushing the slag to get the iron prills Separated iron and slag Panning, the crushed slag, to obtain more iron Separating the heavier iron from lighter slag. This technique has improved the recovery of iron from each smelt. The result is tiny, prills and metallic iron dust that can be melted together later I keep the slag to be re-smelted later, as there may still be iron chemically bound to it.
Total iron recovered was 34 g. The third highest amount I’ve produced in the wild I’ll, try to melt it into something later, along with the other iron. I’Ve been saving from smelts All the iron. I’Ve got so far. Wood ash insulated furnace .