When it comes to ceramics, besides clay and glaze, another crucial factor that should not be overlooked is the "kiln atmosphere." This is because the firing atmosphere determines the color and surface of our ceramic work.
Most ceramists may be familiar with the terms Oxidation atmosphere or Reduction atmosphere, but did you know there's another atmosphere that represents a perfect balance: Neutral Atmosphere? Today, Pottery Clay will delve deeper into this.
What is Neutral Atmosphere?
Neutral Atmosphere is a condition inside the kiln where the proportion of "fuel" and "oxygen" is perfectly balanced, resulting in complete combustion without excess oxygen and without fuel lacking oxygen drawing elements from the clay and glaze.
Simply put, it's a state that lies between:
- Oxidation Atmosphere: where there is an abundance of residual oxygen.
- Reduction Atmosphere: where there isn't enough oxygen, causing the fuel to "steal" oxygen from the oxides in the clay and glaze.
Results of Neutral Atmosphere on Glaze and Clay Colors
Firing in a neutral atmosphere has its unique charm and yields stable, natural results, as follows:
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High color accuracy: Metal oxides that provide color (e.g., copper, iron, cobalt) are neither accelerated to react with excess oxygen nor stripped of oxygen. This results in glaze colors that are closest to the standard values according to chemical formulas.
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Natural color tones: Especially suitable for glazes that require softness, balance, not as flamboyant as oxidation, and not as dark or mottled as reduction.
Consistent clay body: Helps the clay body to mature well without issues of black core, which often results from incomplete combustion.
How to Control the Kiln for a Neutral Atmosphere?
Maintaining a neutral atmosphere in the kiln is a technique that requires considerable skill (especially with gas or wood-fired kilns).
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Adjust the damper precisely: Airflow and flue must be balanced. Do not open too wide, which would lead to oxidation, and do not block too much, which would lead to thick smoke and reduction.
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Observe the flame: In a neutral state, the flame is often a clear, soft yellow to light orange, without thick black smoke, and without excessive gas injection noise.
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Use an electric kiln as an aid: If using an electric kiln, the atmosphere generally leans towards oxidation. However, with proper ventilation control, it's possible to simulate a state very close to a Neutral Atmosphere, which is the most stable and easiest method.
Understanding Neutral Atmosphere will provide you with more creative options for your work. If you desire consistent glaze colors, easy quality control, and natural color tones, neutral firing is an answer not to be overlooked.
If you are looking for high-quality ceramic clay, ready-made glazes, or advice on ceramic kilns, come and talk to us at Pottery Clay. We are ready to assist you in every step of your pottery journey.