If you’re a potter, ceramic artist, or hobbyist looking to fire clay, you may not be aware of all the ways you can fire your pieces. Understanding the different methods is essential to making a wise choice when deciding which firing method to use. Read on to learn the 7 most common methods of firing clay, each of which has its own benefits, drawbacks, and considerations.
Overview of Clay Firing Methods
In order to make quality products with clay, the pieces must be fired in order to remove excess moisture, dry the clay, and set the glaze. There are a variety of methods for firing clay, ranging from traditional kiln firing to modern electric resistance heating (or ERH) firing. With so many options, it’s important for potters, ceramic artists, and hobbyists to research the individual options and make an educated decision when deciding which method to employ.
Kiln Firing
Kiln firing is one of the oldest and most well-known methods of firing clay. This type of firing uses a specially-built oven to bake the clay in a heat-controlled environment. Depending on the type and size of the kiln, temperatures can reach up to 2000°F (1093°C). The length of the firing and temperature required depend on the type and size of the clay piece being fired. Kiln firing involves slow heating and cooling techniques, and is best used for producing vessels and other hard white wares.
Raku Firing
Raku firing is a popular firing method used by potters and ceramicists. Originally developed in Japan, this method produces dramatic results by rapidly heating a ceramic piece and quickly cooling it. To do this, potters typically heat their pieces in an outdoor kiln or in a gas or electric kiln, then transfer them to a container of combustible material such as sawdust or straw. Raku fired pieces often have unique color combinations, due to the high temperature and rapid cooling process.
Pit Firing
Pit firing is an ancient and primitive method of firing clay that is still used by potters today. Pieces are placed into a shallow hole in the ground and then heated with burning wood or charcoal. Since this method does not involve careful temperature control or any sophisticated equipment, pit firing typically produces unique, unpredictable results. Commercial potters also use this method to create unique effects on their work.
Saggar Firing
Saggar firing is an advanced firing technique used by professional potters. During saggar firing, pieces are placed inside a tightly-lidded saggar (a sealed earthenware container) with combustible material such as straw or sawdust. The saggar is then put inside a kiln, where temperatures will reach 1500°F (815°C). The combination of the combustible material, hot air, and carbon dioxide causes deep colors and patterns to occur on clay pieces.
Barrel Firing
Barrel firing is another traditional way of firing clay that produces unique results. Pieces are loaded into an upright barrel, which is filled with combustible materials such as wood chips, sawdust, paper, or straw. The barrel is then fired for several hours until the pieces have reached the desired temperature. Barrel firing offers unique effects due to the unpredictable nature of its heat sources.
Gas Reduction Firing
Gas reduction firing is a modern cutting-edge process that uses a combination of oxidizing and reducing gases to produce beautiful results. During this process, pieces are placed in a kiln and slowly heated while special gases (such as carbon dioxide) are released into the environment. The effects of gas reduction firing range from beautiful pale blues to bright reds and oranges.
Electrical Resistance Heating (ERH) Firing
Electrical resistance heating (ERH) firing is the newest type of firing available. This firing process uses electrical current to heat metal plates or coils in order to warm a kiln, with the plates and coils acting as resistors. ERH firing has become increasingly popular as it is more precise than traditional methods and can be more efficient. Potters using ERH will often want to invest in additional equipment such as thermocouples, PID controllers, and refractory boxes.
Electric Kiln Firing
Electric kiln firing uses electricity instead of gas or other combustible elements to heat the kiln. This process is much cleaner than traditional methods and has become increasingly popular due to its precision and efficiency. Electric kilns come in a variety of sizes and can produce temperatures ranging from 150°F (65°C) up to 2200°F (1204°C). Electric kilns are also great for producing glaze effects as they can be easily regulated for temperature.
Wood-Fired Kiln Firing
Wood-fired kiln firing has been around for centuries and still remains popular today. This method relies on wood-fueled fireboxes that can create temperatures up to 2300°F (1260°C). Pieces are placed into chambers connected to the firebox, where they are heated indirectly by hot air produced by the firebox. Wood-fired kilns produce beautiful results due to their unpredictable nature. However, due to the complexity of this method, it is not recommended for novice potters.
Considerations When Choosing a Clay Firing Method
When choosing a clay firing method, there are several things that potters need to consider. Cost is always a factor when selecting an appropriate method; some methods require sophisticated equipment and special materials which can be costly. Time is also an important consideration; some methods such as ERH may be faster, while others such as pit or barrel firing may take far longer. Additionally, traditional methods are typically slow and require careful monitoring; modern methods such as electric or gas can be sped up with minimal monitoring.
In summary, each method of firing clay has its own unique benefits, drawbacks, and considerations that potters need to take into account when selecting which process is right for them. Researching each option in depth will provide valuable insight into what works best for any particular project.
