Primitive Technology: Crossdraft kiln

Scribbing kiln footprint (about 85 cm by 25 cm) crushing up pieces of old furnace water mixing mud layer 1 digging out pit for fire box layer 2 layer 3 layer 4 layer 5 making top of side walls curved to form an arched profile (from front to back) bridging the gap with sticks adding mud roof.

The curved profile helps prevent roof collapse building the chimney to create the draft effect digging a side door to access the pottery adding to chimney making grate bars from clay adding side shelves to hold grate bars installing grate bars.

These hold the fuel off the ground so air can come up through the fuel bed, increasing combustion efficiency several times.

Making fire with firesticks fire started at entrance of firebox crossdraft effect working chimney draws hot air through kiln adding to chimney as fire helps dry it creek bank digging clay clay into pit slake with water crushing old pottery as grog (prevents clay from cracking during firing) at hut wood ash to stop clay sticking to rock lump of clay form an " ash tray" as the base of pot add coils of clay to increase height some time was left between adding layers so that the pot stiffened as it was being built.

This prevents slumping. Adding a spout putting pot in kiln closing up kiln door sealing door shut with mud starting fire in ash pit of loaded firebox so that the wood on the grate bars catches fire flames travel right to the back of the kiln almost immediately you can just see the edge of the pot through the top of the chimney in about 30 minutes flames reach the top of the chimney about an hour in pot is glowing orange hot at about 1 hour 20 minutes opening kiln about 4 hours later taking out pot carefully fired pot water test holds water and pours it satisfactorily making a new kiln, and so the cycle repeats.

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