How to do a Black-Firing
Black-firing is an ancient, simple, low temperature firing technique.
The method described here involves heating a primitive gas-brick kiln
to about 1000oC and then adding sugar, which then volatilizes
and impregnates the clay with carbon, giving it a matt black surface.
Difficulty Level: average Time Required:
- Stack the black-fire kiln carefully so that flames will wrap around
the work and exit the flue. Work placed near the flue will receive more
- If using glazes, place glazed test rings near the spy hole to check
the glaze maturation during the firing.
- Place a cone 013 (855o C/1565o F) in the kiln
and insert a pyrometer if available.
- Begin the firing slowly for the first hour and then turn up the gas
pressure every hour for up to 5-6 hours.
- Shut off the gas and seal the flue and any cracks.
- Push in up to 16 pounds (5-8 kg) of sugar into the burner port and
then seal the port with bricks and fire clay. (A good gas mask and heavy
duty leather gloves should be worn at this stage.)
- Make sure all cracks, where smoke is billowing out, are sealed with
fire clay as well as possible.
- Allow the kiln to cool overnight and open the next day.
- Remove excess scum with a wire brush under a running tap.
- Use old kiln shelves.
- Keep a long, thin metal rod handy to pull out test rings.
- Be sure to wear a gas mask, not just a dust mask, when adding the
sugar -- the fumes are toxic!