Hi, this is Wayne again with a topic “Primitive Technology: Downdraft Kiln”.
Digging soil with a hoe made from a tree with a 90 degree buttress root, Making mud Palm leaves for fiber to stop mud, cracking as it dries Forming. The firebox 25 cm wide About 50 cm long. Banks are added to support grate bars, Grate bars, made of clay ( 25 cm long ) Dry. It out. Install grate bars, Start the floor of the ware chamber, leaving a 6.25 cm gap from the back for the entry. Flue Use wood to support the clay floor Plaster over the wood to form the floor, Leave a gap for the entry flue Firebox, complete Start.
The ware chamber Leave a 12.5 x 12.5 cm square hole for the exit. Flue Continue the walls upwards Bridge over the exit, flue Form, arched, roof profile, 12.5 cm high and 25 cm long Form. The roof Ware chamber completed, Cut a door into the side, Make a door from clay to close the kiln during use the hole in the door, acts as a peep hole and a hold for a stick to lift it out Now build a chimney to increase the Draft Chimney completed ( about 1.5 m total height ) Flame forms, an arch as it moves through the ware chamber.
Flames come in through the entry flue Up into the ware chamber And then back down through the exit, flue (. Hence the name down draft ). I enlarged the exit flue, so it now behaves more like a cross draft, hoping it will draw a stronger draft Digging clay for pots, Preparing to levigate clay to remove impurities. Add water Release, clay water slip into lower pond Wood shavings, stop twigs/leaves flowing into the pond.
The upper pond has gritty impure clay. The lower pond has smooth pure clay Scooping out the clay Crushing pot sherds for grog Mixing clay with grog ( stops clay from cracking when fired ) Forming a simple pot over an previously fired pot Stacking. The kiln, with pots Sealing the kiln with door Fire by friction, Starting the fire under the grate, Adding wood on top of the grate, The wood catches fire and the kiln starts to draw a draft. The pots can be viewed through the peep hole in the door.
In about an hour, the pots are this hot: The door is opened later when it is cool, The pots were fired well, but the clay was poor quality.. Next time, clay from the river should be used. .