Pottery by Judy Thompson
How Pit Firing is Done
The pots are thrown on a potter's wheel. When trimmed and dry, they are hand burnished 3 times with a fine terra sigilatta clay slip. Next they are bisque fired in an electric kiln to harden them. After the bisque firing, they are very shiny and white.
The bisque fired pots are loaded into the pit on top of a thick layer of sawdust. The pots are surrounded with lots of salts...table salt, kosher salt, sea salt, rock salt, Epsom salts. Next, powdered dry coloring oxides...such as copper carbonate, iron oxide, and rutile...are sprinkled over and around the pots. Other chemicals used are copper sulfate and ferric chloride. During the firing the salts melt and vaporize. The sodium vapors swirl around the pots and react with the oxides and chemicals, leaving clouds of colors and patterns on the sides of the pots that are permanent markings.
After adding all the oxides and salts and organics...the pots are completely covered with more sawdust, followed by small twigs and branches, to cushion the pots even more. This is topped off with a layer, about 2 feet thick, of larger branches of wood. The entire pile is lit on fire, and burns intensely for about an hour...while I continue to add more wood. After about an hour, I stop adding wood, and when the flames die down a bit, the entire pit is covered with sheet metal, and allowed to finish burning very, very slowly. I leave the pit alone for about 2 days to make sure everything has completely burned out.
When the pit is opened...the pots are removed and the lose ash and mineral deposits are dusted off. Next comes the cleaning up phase, which requires a lot of "elbow grease". When the pots are completely clean, 3 layers of hard paste wax are applied. Each pot is polished to a high sheen to accentuate the richness and beauty of the colors and textures. Each pot is truly "one of a kind".
