What Is Saggar Firing
A saggar is a container — traditionally refractory clay, but aluminum foil works for modern potters — that encloses a pot along with combustible materials during firing. The saggar creates a sealed environment where gases, smoke, and vapors interact with the clay surface. The result is dramatic, colorful surface effects more controlled than pit firing but more unpredictable than glazing.
Stephen Jepson introduced saggar firing to his UCF students as a bridge between primitive firing and kiln technology. The technique produces gallery-quality surfaces while teaching atmospheric chemistry.
The Saggar Firing Process
Preparing the Pot
Start with a bisque-fired pot — ideally burnished or coated with terra sigillata. Burnished porcelain produces the most vivid results because its white, smooth surface shows every color change clearly. The pot should be completely clean.
Building the Saggar
For beginners, heavy-duty aluminum foil is easiest. Double layer, large enough to wrap completely with room for materials. Traditional saggars are thrown or slab-built from refractory clay and are reusable.
Packing the Saggar
Layer combustible materials around the pot:
- Copper wire, carbonate, or scrub pads: Greens, pinks, and reds.
- Salt or salt-soaked newspaper: Orange, amber, golden flashes.
- Steel wool: Gray, black, metallic marks.
- Banana peels: Dark spots and organic patterns.
- Seaweed: Linear impressions and dark marks.
- Sawdust: Overall carbon fuming.
- Ferric chloride: Warm amber and gold tones.
Place materials in direct contact with the pot where you want color. Areas between materials develop softer transitions. Keep notes so you can learn from each firing.
Firing
Place the packed saggar in a kiln and fire to cone 06 through cone 04. Fire slowly — eight to ten hours — to allow full combustion and vapor deposition. Ensure good ventilation since combustion produces smoke.
Opening and Cleaning
Wait until completely cool. The anticipation is part of the experience. Unwrap carefully. Brush off ash and residue. Apply paste wax to deepen colors and add a protective sheen.
Controlling Results
Material Placement
Where you place materials determines where colors appear. Wrap copper spirally for stripes. Pack salt on one side for a gradient. Nest in sawdust for overall carbon. Careful placement gives significant creative control.
Temperature and Timing
Higher temperatures produce more intense colors. Longer firings allow deeper color penetration. A slow ramp through the critical range gives materials maximum time to interact with the clay surface.
Record Keeping
Keep detailed notes: materials, quantities, placement, firing schedule, and results. Photograph the packed saggar before sealing and the finished pot after opening. Over time, your notes become an invaluable reference.
Learn from Stephen Jepson
Stephen's pottery video lessons cover surface preparation, burnishing, terra sigillata, and firing techniques essential for saggar firing. One-time purchase, lifetime access.