October 2, 2023

Understanding Saggar Firing in Pottery

Discover saggar firing - the magical pottery technique that uses specialized containers to protect wares in the kiln.

Saggar firing

What are those weird vessels stacked inside pottery kilns, filled with curious materials? They are saggars - specially designed boxes used in the distinctive saggar firing technique. Let's unpack how saggars work and the dazzling effects they can create.

What is Saggar Firing?

Saggar firing refers to placing wares like pottery inside protective containers called saggars during kiln firing. Saggars shield pieces from direct flame or heat. Combustible materials are added inside the saggars to generate special surface effects.

Saggars act like mini-kilns, creating small controlled environments with their own atmosphere. As the saggar contents burn, gases alter the clay and glaze inside. Saggar firing adds mystery and serendipity to a pottery piece.

The Role of Saggars in Firing

Saggars perform several important roles:

  • Protect fragile or intricate pottery from heat shock
  • Shield glazed surfaces from direct flame
  • Contain combustibles that alter the interior atmosphere
  • Prevent carbonaceous materials from contaminating the kiln
  • Allow use of materials that burn at lower temperatures

The saggar box is critical for managing the small atmosphere that impacts the pottery wares during firing.

Saggar Design and Placement

Saggars are lidded containers made of high-fire clay or refractory materials. They are shaped like boxes, cylinders, or trapezoid forms. Small ventilation holes allow the passage of heat and gases.

Saggars are positioned carefully on stilts inside the kiln to surround pieces on all sides without touching. Several saggars can be stacked and cross-stilted for multi-level firings.

Burnout Materials for Saggars

Adding combustible materials to a saggar generates atmospheric effects:

  • Sawdust - Creates strongly reducing conditions and carbon trapping.
  • Seaweed - Produces soda vapors that break down glazes.
  • Dried plants - Cause subtle mottling and flashing.
  • Wood chips - Generate patterned watermark effects.
  • Paper or fiber - Burn out to create grey ash deposits.

As the added materials combust, gases are infused into the clay and glaze inside the saggar.

The Firing Process for Saggars

Firing with saggars involves carefully controlled heating stages:

  1. Load - Fill saggars and position in kiln on stilts.
  2. Bisque - Fire to bisque temperature for preliminary hardening.
  3. Cool - Cool down the kiln and fill saggars with burnout materials.
  4. Low fire - Reheat the kiln to complete combustion in saggars.
  5. High fire - Raise temperature for glaze firing.
  6. Cool - Allow extended cooling for full glaze development.

Following the steps carefully is essential to fully develop the unique saggar effects on the pottery.

Saggar-Fired Results

When done skillfully, saggar firing creates mesmerizing surface patterns and textures:

  • Mottled colors from incomplete glaze reaction
  • Hidden designs from plant ash deposits
  • Dramatic streaking from iron wash interactions
  • Misty watermarked effects
  • Crackled textures from volatilized soda vapors

The atmosphere inside each saggar leaves its distinct mark on the fired clay and glazes.

Types of Kilns for Saggar Firing

Saggars traditionally were fired in wood-burning kilns, but today they can be fired in gas or electric kilns. The best kiln types for saggar firing are:

  • Wood kilns - Allow stacking saggars directly in the firebox for dramatic effects
  • Gas kilns - Offer atmosphere control options with reducing capability
  • Electric kilns - Require some burnout compromises but work well

Any kiln that reaches cone ten temperatures can be adapted for saggar firing.

Tips for Successful Saggar Results

Keys for beautiful saggar-fired pottery include:

  • Test-fire to perfect the timing of burnout materials
  • Use a vented saggar lid or add holes to allow circulation
  • Cautiously preheat and cool saggars to prevent breakage
  • Place saggars for maximum flame exposure and heatwork
  • Refrain from opening the kiln until fully cooled after firing

With testing and fine-tuning, saggar firing's magic transforms pottery into hauntingly artistic works full of mesmerizing depths.

This historic technique mixes science and serendipity for one-of-a-kind ceramic art. The saggar envelops clay in its transformative powers.

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