Alexander went to observe the lost wax casting method at the decorative section of the iron workshop, where things like statues and other showpieces were being created.
In this casting method, first, a wax model of the product was created.
Then it was coated with clay or in the case of Alexander, plaster of Paris, which was just powdered gypsum mixed with water, with only a few small holes at the sides and top.
Once the coating set, the entire was heated in an oven to melt the wax and let it drain out of those holes.
Then molten iron could be poured from the nearby furnace using a crucible into that small hole, thus creating a precise replica of the original wax model.
After that, all that remained was to wait for the metal to cool and solidify within it.
Once that was done, the ceramic shell was broken away to reveal the metal casting inside.
The product was then grinded, sanded, polished, and colored to give the appropriate finish.