The pattern needs to be tighten up, to maximize primary air flow.
Hand tools and a bit of patience and the job is done.
When the bottom is ready, the next step is to cut the top edge of the combustion chamber: this allows secondary air to ignite the gasses and burn them completely...
These regular yellow ovals were really helpful to space the cuts.
The last set of holes is the six holes that help feeding the fire at the beginning: they also set the maximum level of the combustion chamber. This particular one is not as tall as I would like it to be... but it's going to be a nice test anyway.
In the next days we'll light it up, as soon as it stops raining and we get enough dry biomass to fill it up. Really looking forward to see how it goes!