My Pottery Blog

Burn, Baby Burn (A pit-firing picture diary)

Pit firing 8/4/07

An innocent pile of bisque-ware, awaiting their fiery trial...

The initial chemical coatings; computer etchant (ferric chloride) and a thin mixture of cobalt water
Selected pots are painted with a 1/2 water 1/2 etchant solution (warning--be sure to use gloves and plastic coatings on surfaces whenever dealing with ferric chloride.)
Pots painted in ferric chloride are wrapped with copper carbonate, hay, salt, and cut-up copper scrub pads.

Salt and copper carbonate are sprinkled liberally on a bed of hay on top of a sheet of newspaper. The pot is placed on the hay bed, then coated with scrub pad pieces, more salt, copper carbonate, and a sprinkling of hay.

The whole thing is wrapped loosely and secured with a little bit of tape (any kind will do)

Other pots are selected for a Cobalt treatment.
The Cobalt pots will be coated with hay, Miracle Gro, and salt.

They are layered and wrapped in the same fashion as the etchant vessels

All the pots are packed away to take to the firing site. As a bonus, the newspaper wrappers also keep the pots from getting broken on the way.

Supplies that I bring to a pit firing; more copper carb, salt (table and rock), sawdust, matches, newspaper, red iron oxide, lighter fluid, more hay, and wood chips.

The back of my car all loaded and ready to go

The empty fire pit

I create a bed of chemicals and combustibles for the pots to rest on. This includes (from bottom to top) charcoal from any previous firings, large wood chips, sawdust, rock salt, copper carbonate, and red iron oxide.


Newspaper bundles are gradually layered on this bed with kindling
Hay and more chemicals (salt, red iron oxide, and copper carb) are added loosely to the growing bonfire.

When the whole thing is piled up, it is doused with lighter fluid and lit on fire.

Burn, baby burn!
Sometimes when logs settle, I can actually see pieces in the fire while the flames lick them. I don't stoke the fire after the initial building, I'll just adjust logs occasionally for even heating.

Unfortunately, during this fire, it started to rain. The cloud just sailed in from nowhere. The fire still burned, but was not nearly as hot and did not go for nearly as long. As you can see, some of the logs didn't burn all the way down. As it looked like it might rain again, I cut my losses and let it cool down rather than re-positioning and re-lighting.

The hot pieces waiting to be pulled from the ashes

Pots are placed on the stones around the fire-pit to cool down

The pots wait to be packed back up in newspaper and taken home for cleaning and sealing

Results


Some nice oranges, reds, and pinks came out on the Ferric Chloride treated pots.

I wasn't very happy with the Cobalt pots this time around. They needed to get much hotter than they did to receive the characteristic blue blushing from the cobalt/miracle gro combination. Some pots had still-interesting black, brown, and tan coloring. These I kept and sealed (see next two pictures).

Two had nearly no coloring at all. These I will re-fire.