This is my charcoal forge built from a cast iron bell housing from a amphibious assault vehicle, this is where the propeller comes out.  I've still got to add the blower, I'll post more pics after the blower is installed.

 

 

 

 Closeup showing the air grate, lot of drilling

 

 

 

  Here's the forge after installing a blower from my shop vac. 

The air flow is controlled by a valve system that re-directs the airflow ether up or down.

 

 

 

 

Cut-a-Way View of the Forge