The old way I used to melt down metals was by a coal furnace, however it took a while to reach melting temperatures, it also consumed lots of coal.
Ive since been building an Electric Arc Furnace (EAF) which has proved to be much more efficient at doing the job, while reaching much higher temperatures too, and no coal consumption.
This combined with C.A.D and 3.D Modelling skills will allow us to 3.D print patterns to use in processes like sand casting, hence creating the designed model out of the chosen metal.