Kiln Types & Parts

Ware chamber
(also see illustrations in text, Hands in Clay, pages 21, 64, 343–344)

Kilns at SLCC-FV

Heat Source Cone Atmosphere—Special Use Draft Load From Building Material
Natural Gas 10 Reduction Up Front Refractory
Soft Brick
Electric 04 Oxidation None Front Refractory
Soft Brick
Natural Gas 06–04 Raku:
Oxidation + Reduction
Up Top Hat Refractory
Soft Brick
Wood 010 Reduction Up Top Refractory
Hard Brick
Sawdust 010 Reduction Up Top Garbage Can / Bricks

Loading the Chamber with ware

  • Load ware from the front, top, or "top hat" (kiln chamber raised off base by pulley)
  • Bisque and Glaze firings are stacked differently. Work will move as it shrinks in firing. Pieces can touch or be stacked on each other carefully in a bisque firing, but usually not in the glaze firing. Allow enough space around ware for even distribution of heat toward the center of the stack.

Type of Draft and its Control by Damper

  • Updraft—exit port is at the top
  • Downdraft—exit port is at the bottom
  • Crossdraft—burners set up so that flames cross.
  • Muffle—heat is channeled through tubes or by bag walls, to protect the ware a direct hit from the flames.

Kiln Structure

  • Shape—square/rectangular, cylinder/hexagon
  • Type of top arch - catenary, Roman/sprung arch, dome

Kiln Building Materials

  • Refractory brick: 1) soft insulating, 2) hard. Soft brick is lightweight and can be cut easily with a hand saw, but is not acceptable for salt or woodfire kilns. Hard brick is heavy and useful for salt of woodfire kilns, and for lining fireboxes. Both are rated for heat tolerance as K23 (2300°F), K26, K28, etc.
  • Fiber: “Kaowool” or other brands of flexible refractory blanket looks similar to thick cotton quilt batting. It makes a very light weight insulating layer, can be fastened into a light wire framework for a top hat type kiln. Caution: after firing it becomes brittle and it is harmful to breath the dust created when it is moved.
  • Other: earth as in hillside kilns, shallow pits.

Kiln Room or Yard Requirements

  • VentilationALL kiln rooms must have adequate fresh air intake and a good exhaust system to carry away heat, carbon monoxide, and other metal fumes. This applies for both gas and electric kilns. Do NOT sit by a kiln, even if the room is vented. Carbon monoxide poisoning makes you feel drowsy and unable to save yourself.
  • Safety— always check with local fire codes, and comply with them. Have licensed professionals install the gas or electric service, and have it inspected by local officials. Make sure that your insurance coverage is adequate and up to date. Many potters have lost everything due to carelessness.