What are Signs of Over-Firing in Primitive Pottery?

Identifying Signs of Over-Firing

When primitive pottery is over-fired, it can be difficult to recognize the extent of the damage. A cracked or broken vessel is an obvious sign, but it may also appear slightly wavy or distorted. Discoloration can range from a subtle darkening of the surface to a severe, charcoal-like coloration. Over-firing can cause the clay to become brittle and prone to cracking.

Causes of Over-Firing

Over-firing can result from firing the pottery at too high a temperature, or for too long a period. When working with primitive firing techniques such as pit firing, it can be difficult to control the temperature accurately. This is particularly true for coil method pottery, where the thickness of the walls can affect the firing time. If the pottery is fired too quickly, it may not have sufficient time to harden, leading to cracking and other signs of over-firing.

Prevention and Correction

To prevent over-firing, it’s essential to carefully monitor the firing temperature and time. This can be achieved by using a makeshift pyrometer or by observing the color of the pottery as it fires. A more accurate temperature control can be achieved by using a thermometer or by firing in a kiln. If over-firing has already occurred, it may be possible to correct the damage by applying a waterproofing treatment, such as beeswax or plant resin. This can help to seal any cracks and make the vessel more watertight.