6.Firing in Kiln: The Final Step to Transform Clay into Ceramic Art

Master Kiln Firing Techniques for Stunning Glaze Results

🌐 What is Kiln Firing?

Kiln firingΒ is theΒ high-temperature processΒ that transforms raw clay and glazes into permanent ceramic ware. It involves preciseΒ temperature controlΒ andΒ atmosphere managementΒ (oxidation/reduction) to achieve desired colors, textures, and durability.

πŸ”₯ Why Kiln Firing Matters

Transformation Scientific Explanation
Clay to Ceramic Quartz in clay melts, forming a glassy matrix
Glaze Vitrification Glaze turns into a glass-like coating
Color Fixation Metal oxides in glazes react to heat/atmosphere

πŸš€ 5-Stage Kiln Firing Process

"how to fire pottery in a kiln"

1. Pre-Firing Preparation

  • Load Kiln:
    • Place pieces with thick glazes at the bottom (the area where the glaze tends to sink).
    • Use kiln posts to support tall vessels and leave a 2-cm space for heat dissipation.
  • Check Tools:
    • Calibrate the temperature with a thermocouple and program the kiln controller.

2. Oxidation Stage (25–900Β°C)

  • Objective: Remove moisture and organic matter.
  • Heating rate: 150–200Β°C per hour.
  • Observation: The greenware changes from earthy yellow to grayish white.

3. Reduction Stage (900–1200Β°C)

"reduction firing for ceramics"

  • This stage is only applicable to reduction glazes (such as copper red glaze and celadon).
  • Operation: Reduce oxygen supply and increase fuel (pinewood/natural gas).
  • Function: Metal oxides are reduced to lower valence states, showing red or cyan colors.

4. Peak Temperature Holding

  • For transparent glazes: Hold at 1000–1100Β°C for 30 minutes.
  • For colored glazes: Hold at 1200–1300Β°C for 1 hour.
  • Professional tip: Observe the melting state of the glaze at high temperatures (e.g., mirror-like reflection).

5. Cooling Phase

  • Rapid cooling (used for Raku): Remove the pieces at 1000Β°C and place them in wood chips for carbonization.
  • Natural cooling: Allow 24–48 hours (to avoid glaze cracking).

πŸ”§ Kiln Types & Features

"types of kilns for ceramics"


Kiln Type Fuel Temperature Range Best For
η”΅ηͺ‘ (Electric) electricity 1200–1400Β°C Precisely controlled glaze colors (such as those of blue and white porcelain)
燃气ηͺ‘ (Gas) propane /natural gas 1300–1600Β°C The effect of reduction firing (such as the kiln transformation in Jun Kiln)
柴ηͺ‘ (Wood) wood 1100–1350Β°C Natural ash glaze and fire mark texture

⚠️ Common Firing Mistakes

Poll:
"Which firing technique fascinates you most?*
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