16/09/2026
💥 Why Ceramics Explode in the Kiln (and How to Fix It!)
🔥 Bisque Firing Disasters
Bisque explosions are almost always caused by trapped moisture:
• Damp Clay: Even if your piece feels dry on the surface, moisture can still be trapped deep inside. Once the kiln hits 100°C, that water turns into steam. If the ramp-up speed is too fast, the steam can’t escape through the clay’s pores, causing intense pressure and an explosion.
• Uneven Thickness: Extra thick bases or heavy walls take much longer to dry completely through.
✨ Glaze Firing Disasters
Glaze explosions and catastrophic cracks are usually triggered by moisture, thermal shock, or material stress:
• Hidden Moisture: Wiping down bisque ware with a wet sponge—or rinsing it under running water to clear dust—adds water back into the clay. Plus, some glazes have a high water content. If you don‘t allow enough drying time before firing, trapped steam will cause trouble.
• Mismatched Clay & Glaze Expansion: When the thermal expansion coefficients of your clay body and glaze are too far apart, extreme tension builds during cooling, which can snap or shatter your piece.
• Thermal Shock: Heating up or cooling down too quickly creates intense stress. Around 573°C (the quartz inversion point), clay undergoes rapid expansion and contraction. Firing too fast or opening the kiln door too early can easily shatter your work.
🛠️ How to Prevent Kiln Disasters
• Ensure 100% Dryness: Allow plenty of drying time, especially on wet, rainy days when humidity is high. Keep wall thickness as even as possible.
• Dry After Glazing: Give your pieces ample time to dry thoroughly after washing or glazing before loading them into the kiln.
• Test Compatibility: Run a test tile first to ensure your clay and glaze expand and contract nicely together.
• Master Your Firing Program:
！！ Slow down your firing ramp around 573°C.
！！ Resist the urge to unpack early! Wait until the kiln drops below 100°C before opening the lid.
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https://www.instagram.com/clayrealmstudio/
