Fire that turns clay into stone – the magic of firing ceramics

Firing is one of the most important stages of a ceramicist's work. It's a process in which soft clay becomes a durable material that withstands time. The type of kiln, temperature, and technique determine the final appearance and properties of the vessels. Let's explore the differences between electric, gas, wood-fired, and raku firings, and why, for many ceramicists, firing day is the most important moment in the studio.

What is ceramic firing?

Firing involves heating formed and dried ceramic pieces to very high temperatures. During this process, the clay particles sinter, making the material harder and less absorbent. The type of firing determines not only durability but also the surface appearance and color of the vessel.

Types of firings

Firing in an electric kiln

This is currently the most popular method. Electric kilns allow for very precise control of temperature and firing curve. This gives the ceramicist a great deal of control over the process, and the results are repeatable. Temperatures in such kilns typically reach 1000-1300°C, depending on the type of clay and glaze.

Firing in a gas kiln

A gas kiln allows for reduction effects, which change the color of the glaze and clay by limiting the access of oxygen. This process produces deeper, more varied colors and surfaces that are difficult to achieve in an electric kiln. However, it requires experience, as controlling the atmosphere in the kiln is not easy.

Firing in a wood kiln

This is one of the oldest techniques, used by ceramists for thousands of years. The wood-fired kiln operates continuously for several, even several dozen, hours. The fire and ash leave natural marks on the vessels: burnt fragments, ash-based glazes, and uneven surfaces. Each firing is unique, and the results depend on the type of wood, temperature, and firing method.

Raku firing

The raku technique originates from Japan and is characterized by its rapidity. Works are fired in a gas or wood kiln to temperatures of approximately 950-1050°C, then removed while still hot, and placed in a container filled with sawdust, leaves, or paper. The rapid cooling and lack of oxygen cause the characteristic crackle effect and intense colors. Each piece is absolutely unique.

Orton's Temperatures and Cones

Firing ceramics requires temperature control. In practice, ceramists use so-called Orton cones, which react to heat in a similar way to clay and indicate the moment when the material reaches the proper degree of sintering. This is important because the kiln temperature itself does not always reflect the actual conditions inside.

• Faience is usually fired in the range of 950-1050°C.

• Stoneware requires higher temperatures, 1180-1250°C.

• Porcelain requires up to 1300-1400°C.

Firing day in the studio

Preparation for firing begins with glazing and carefully arranging the pieces in the kiln. This takes several hours in an electric kiln, even days in a gas or wood-fired kiln. Once the temperature is reached, the kiln must cool for another 24 hours, sometimes for a further 24 hours. Only then can the door be safely opened and the results seen.

For a ceramicist, it's a moment fraught with emotion. Every firing is a test of technique and patience. Not everything always works out; vessels can crack, the glaze can run, or change color. But it's precisely this unpredictability that makes firing so fascinating.

Fire and personal development

Fire teaches patience and humility. The moment the kiln is closed, the ceramicist loses control and must trust the process. This experience is very similar to everyday life: we prepare and plan, but there are moments when we must let things unfold at their own pace.

Working with fire has a cleansing effect. It gives one the feeling that change, though difficult, is possible. Just as clay never returns to its former form, a person becomes stronger after experience.

Our path to the fire

The first kiln was installed in our studio in 2018. Then came the raku kiln, which opened up a world of dramatic effects and unique glaze cracks. Eventually, we built a magnificent wood-fired kiln that gives the vessels a unique character and allows us to fully experience the magic of contact with fire.

Each of these kilns taught us something different: the electric one, precision; the wood-burning one, courage; and the wood-burning one, patience and teamwork. Thanks to them, we understood that firing is not just a technique, but a path worth following step by step.

Summary

Firing ceramics is a process that combines technique with unpredictability. Electric kilns offer control, gas kilns offer rich colors and reduction, wood kilns offer natural fire patterns, and raku kilns offer unique crackle effects and intense colors.

For a ceramist, fire is not only a working tool, but also a teacher of patience and a symbol of transformation.

Dariusz Leszczyński
co-founder of Boscoo Ceramic