As mentioned yesterday, we planned to light our first fire today to assist with drying out the 1st and 2nd layers of the dome, bring out the cracks so we can fill them in, and test the height of the door.
We learned via the magical internet, that the perfect height for the door opening is 63% of the internal height of the oven ceiling, so that’s how high we cut the door at.
Apparently the height has to be a somewhat perfect balance between retaining the heat in the dome, and allowing the smoke to escape reasonably freely without pooling in the ceiling of the dome. Also it is meant to not let the smoke esape too freely, because otherwise heat is lost.
So the first fire is all about finding the balance between heat retention and smoke release.
We were fairly confident that since we’d followed the ‘magic number’ of 63% that we’d be fine, and even after reading about all the mishaps people had with their first fires, including the oven falling completely apart, and the oven exploding and shattering, we still thought that we’d probably be OK.
And we were right. For the first 4 hours or so we just had a candle going inside the oven, and we were impressed by how lovely and warm it got with just the heat from the candle. All seemed to be working according to plan.
After the heat from the candle had warmed the oven up quite a lot, we decided it was time to light a small fire to really see if it was going to withstand the heat, and to get some smoke going to test the door.
We foraged around town for some suitable burning material and found some dead palm fronds, so used them to start the fire. After a while Korlee and Toc decided to find some sticks and bamboo, which made the fire bigger.
After an hour or so we decided that we had the perfect balance between heat, smoke escaping, and accessiblilty to the oven with the pizza peel so the door height was left as is. The oven got very warm to the touch but not really hot, which seems to be fairly perfect for the first fire judging by others accounts on the internet. Some smoke escaped through the cracks, and we were careful to not let the fire get too big this time.
We had expected the bamboo cage to burn out, this time though it stayed intact so we guess that next time we light a fire, or whenever it is that we let it get really hot inside, it will burn away.
The next step will be plugging the cracks, and building the rest of the insulation layer.