Here's a detail of the sandy base where I've set the stove.
To close the primary air and extend the duration of the process, it's enough to pack up a bit of sand around the base of the stove. In this simple way we can control the amount of air that comes in the combustion chamber.
Hold on for a bit more until we start to set up workshops and demonstration on this very relevant issue. The smokey season is coming up soon here... got to get ready as soon as possible!