What Is The Purpose Of A Kiln?
An electric kiln is a heating chamber used to process materials at high temperatures. Kilns are insulated chambers that reach high temperatures using either fuel or electricity. A kiln uses a process invented thousands of years ago to harden ceramic bodies. In ceramics, modern kilns are used to fire clay and porcelain pieces. Think of a kiln similar to that of an oven.
Modern Kilns
Clay becomes hard enough to form tiles and vessels when heated properly. Glazes fired on the clay turn into permanent decoration. Some of the world’s finest artwork is made of clay. Ancient China’s porcelain is priceless. As history has proved, ordinary clay becomes strong enough through the magic of heat to last many centuries.
My primary use of a kiln is to harden clay into hard ceramic bodies. I have been using exclusively Paragon kilns for years with excellent results.
Ceramic Firing Techniques – Firing is the process of creating ceramics that can withstand a great deal of pressure. The firing occurs in an oxygen-rich environment. When it comes to firing pottery, there are two basic approaches. The two procedures are kiln firing and open firing. Firing is a critical stage in the ceramic process. It’s when clay goes from being clay to being useful ceramic.
Electricity and other refined fuels, such as natural gas and propane, were designed into modern kilns. Natural gas is used in a lot of big industrial pottery kilns since it’s clean, efficient, and easy to control.
Computerized controls on modern kilns enable for precision adjustments during the firing process. The temperature rise or ramp, the temperature hold or soak, or the rate of cooling can all be controlled by the user though the use of the computerized control panel.
Smaller scale production and artwork like mine are all commonly done with both electric and gas kilns.
According to Henrik Norsker, A kiln may be described as an enclosure to contain heat. Potters use it to fire their pots and they have developed a countless number of different kiln types, each one reflecting the demands of local markets, tradition, skills and materials. Even so the basics of all ceramic kilns are the same; heat is introduced into the enclosure surrounding the pots. Some heat is lost through the walls or is carried away with the combustion gases, but as more heat is introduced than escapes, the temperature rises and the pots will mature. Henrik Norsker has been making pottery since 1970. He left his pottery workshop in Denmark; in 1976 to establish a pottery school in a village in Tanzania. Since then he has
continued working in developing countries with the promotion of modern pottery. Besides Tanzania
he has been involved in ceramic projects in Nepal, India and Bangladesh. He is presently working
on a pottery project in Burma1.
Handmade Ceramic Fish Wall Art – Colorful ceramic fish wall hanging.
What Are The 3 Types Of Ceramics? – Ceramic or pottery may be divided into three categories: Earthenware, stoneware, and porcelain.
Raku Firing Technique – Raku firing is a type of low-temperature firing. While the pots are still hot and the glaze is still molten, the pottery is taken from the kiln. Stoneware clay is frequently used to make raku. Read the article to discover even more interesting facts about raku.
Berry Abstract Art – Berries are painted using dynamic colors on interesting clay shapes based on nature. Berries are hand formed into clay and then painted natural colors for a unique look.
The temperature of some kilns are monitored by pyrometric cones. These are devices that begin to melt at specific temperatures. Pyrometric cones are used to measure heat in ceramic materials during heating. The cones, which are often used in sets of three, are placed in a kiln with the wares (artwork in my case) to be heated and serve as a visual indicator of when the artwork have attained the desired level of readiness. This is determined by a combination of time and temperature. As a result, pyrometric cones provide a temperature equivalent. It’s important to note they are not simply temperature gauges.
Types Of Kilns That Are Available On The Market
There are many different types of kilns on the market, ranging from small, tabletop kilns for home use to large, industrial kilns used in manufacturing and production settings. The following are some examples of common kilns that I am aware of in no particular order:
- Electric kilns: Are the most common type of kiln and can be used for a variety of applications such as pottery, ceramics, and glass. They run on electricity and are relatively simple to use and maintain.
- Gas kilns: These kilns are commonly used for pottery and ceramics and are fueled by natural gas or propane. They can be more expensive to run than electric kilns, but they can reach higher temperatures and are frequently used for specialized firing techniques.
- Wood-fired kilns: These kilns are commonly used for pottery and ceramics and are fired using wood as a fuel source. They can be more labor-intensive to operate than other types of kilns, but the finished products can have unique and desirable effects.
- Solar kilns: These kilns heat and dry wood, clay, or other materials by utilizing the sun’s energy. They are a greener option, but they may not be appropriate for all types of firing and drying processes.
- Industrial kilns: Are large-scale kilns used in manufacturing and production environments. They can be used for a variety of purposes, such as firing ceramics, drying lumber, and calcining materials. Industrial kilns are typically more expensive and complicated than smaller, home-based kilns.
According to Coll Minogue, The term ‘wood-fired’ is nowadays generally used to describe pottery which has been fired in a kiln fuelled with wood, usually to a temperature of between 1000°C-1300°C. Whatever the design of the kiln used, the principle is the same for them all. Coll Minogue has been a professional ceramist for more than 25 years. She is the author of Impressed and Incised Ceramics and Wood-Fired Ceramics2.
What Are The Different Types Of Materials That Can Be Fired In A Kiln?
Ceramics, glass, metals, and enamels are just a few of the materials that can be fired in a kiln. Ceramics are the most common type of material fired in a kiln, as they are used to make a variety of products such as pottery, tiles, and bricks. Glass can also be fired in a kiln to make a wide range of products, such as stained glass windows and decorative glass objects. Metals like gold and silver can be fired in a kiln to make jewelry or other decorative items. Enamels are commonly used to create a decorative finish on metal objects and are also fired in a kiln.
- Ceramics: Ceramics are nonmetallic, inorganic materials composed of clay and other minerals. When ceramics are fired in a kiln, the heat bonds the clay particles together, resulting in a hard, strong material. Ceramics are used to create a variety of products such as pottery, tiles, bricks, and more.
- Glass: Glass is a clear or translucent material made of silica, soda, and lime. When glass is fired in a kiln, it is melted and slowly cooled, giving it its characteristic transparency and strength. Glass is used to make many different products, such as windows, bottles, and decorative objects.
- Metals: Metals are elements distinguished by their high electrical and thermal conductivity, as well as ductility and malleability. Gold and silver, for example, can be fired in a kiln to make jewelry or other decorative objects. The kiln’s heat causes the metal to melt and then solidify, resulting in a finished product.
- Enamels: Enamels are thin layers of glass applied to metal objects before being fired in a kiln to create a decorative finish. Enamels are well-known for their durability and resistance to wear, and they are frequently used to add color and design to metal objects like jewelry and pottery.
Tips For Choosing The Right Type Of Kiln
These are some things I look for when choosing a kiln. I start off with size because I believe that is the most important consideration.
- Size: The size of the kiln required will be determined by the size of the objects to be fired. Choose a kiln that is large enough to hold your projects, but keep in mind that larger kilns are more expensive to buy and operate.
- Firing temperature: To achieve the desired result, different materials require different firing temperatures. Ceramics, for example, are typically fired at temperatures ranging from 1,000 to 1,500°C, whereas glass is typically fired at temperatures ranging from 500 to 700°C. Make sure to select a kiln that can reach the firing temperatures required for your projects.
- Heating methods: Kilns can be heated in a variety of ways, including gas, electric, or wood. Think about what type of heating will be most convenient and cost-effective for you.
- Additional features: Some kilns include programmable firing schedules, multiple heating zones, and automatic shut-off, which can be useful for certain projects. Determine which features are most important to you and look for them in a kiln.
- Budget: The cost of a kiln can range from a few hundred dollars to several thousand dollars, depending on its size and features. Determine your budget and look for a kiln that fits within it.
How Does A Medium-low Temperature Ceramic Kiln Differ From A Higher Temperature One?
A medium-low temperature ceramic kiln is designed to fire ceramics at temperatures ranging from about 1,100 to 1,200°C, whereas a higher temperature kiln can fire ceramics at temperatures exceeding 1,200°C.
One of the primary distinctions between these two types of kilns is the ceramics they can fire. Earthenware and stoneware ceramics, which are less porous and brittle than other types of ceramics, are typically fired in medium-low temperature kilns. In contrast, higher temperature kilns are typically used to fire porcelain and other high-fired ceramics, which are more porous and brittle than earthenware and stoneware.
Another distinction between these two types of kilns is the time required to fire ceramics in them. Higher temperature kilns fire ceramics faster than medium-low temperature kilns because they operate at a higher temperature.
Finally, due to the additional heating elements and insulation required to reach and maintain higher firing temperatures, higher temperature kilns are more expensive to purchase and operate than medium-low temperature kilns.
What Is The Purpose Of Sprung Arch Kilns In Pottery Making?
Sprung arch kilns are a type of kiln that is commonly used in the production of pottery. They are distinguished by their arched shape, which allows for more even heat distribution throughout the kiln chamber. This makes them ideal for firing pottery because it helps to ensure that all of the pieces are fired evenly and consistently.
Sprung arch kilns are known for their efficiency and fuel savings, in addition to their evenly distributed heat. The kiln’s arched shape allows for more efficient heat and combustion gas flow, which can help to reduce fuel consumption and operating costs.
Other advantages of using a sprung arch kiln in pottery making include the ease with which the kiln can be loaded and unloaded, the ability to fire a diverse range of pottery types and glazes, and the ability to control the firing process through the use of computerized controller systems. Because of their versatility and efficiency, sprung arch kilns are a popular choice for pottery studios.
Tips For Using An Electric Controller Kiln For Residential Use
- Set up and use your electric controller kiln according to the manufacturer’s instructions.
- Ascertain that the kiln is placed on a stable, level surface near an electrical outlet.
- Make sure the kiln is properly grounded in accordance with local codes and regulations.
- To reduce the risk of carbon monoxide buildup, place the kiln in a well-ventilated area.
- When loading and unloading the kiln, wear protective gear such as gloves and a face shield to protect yourself from the high temperatures and hot objects.
- To help ensure even heating, use kiln posts or shelves to support your work.
- To ensure that the kiln is reaching the desired firing temperature, use a pyrometer to measure the temperature inside.
- To ensure that your projects turn out as desired, use good firing practices such as using an even heating rate and soaking the kiln at the appropriate temperature for the required amount of time.
- Keep an eye on the kiln during firing and be ready to turn it off if necessary to avoid accidents or damage.
- Allow the kiln to cool slowly before opening it to avoid thermal shock to the contents.
Does An Electric Kin Come With A Pyrometer?
A pyrometer may be included with an electric kiln, but this is not always the case. Mine did. A pyrometer is a device that measures the temperature inside the kiln and is an important tool for ensuring that your projects fire at the proper temperature.
Some kilns include a pyrometer (like mine), while others require you to purchase one separately. If your kiln does not come with a pyrometer, you should think about purchasing one to use with it. Pyrometers are available at most ceramics supply stores and online.
What To Look For When Monitoring Your Kiln During Firing
There are several things you should look for when monitoring your kiln during firing to avoid accidents or damage. Here is what I look for:
- Check the temperature of the kiln on a regular basis to ensure that it is not exceeding the recommended firing temperature for your projects.
- Any unusual noises coming from the kiln should be investigated because they could indicate a problem with the heating elements or other components.
- Check the power cord and plug for overheating or other signs of damage.
- Check the ventilation of the kiln to ensure that there is enough airflow to prevent overheating and fire.
- To avoid the risk of fire, keep the area around the kiln clear of flammable materials.
- If you notice any problems with the kiln, such as overheating, unusual noises, or damage to the power cord or plug, turn it off and unplug it immediately.
Advantages To Using An Electric Kiln For Pottery Making
There are several benefits to using an electric kiln for pottery production:
- Electric kilns use less energy than gas or wood-fired kilns because they produce no emissions or waste. As a result, they are an environmentally friendly option for making pottery.
- Because they do not require a separate fuel source or venting system, electric kilns are typically easier to install and use than gas or wood-fired kilns.
- Electric kilns provide precise temperature control, allowing you to precisely set the firing temperature for your pottery.
- Electric kilns are typically less expensive to operate than gas or wood-fired kilns because they do not necessitate the purchase of fuel or the upkeep of a separate venting system.
- Electric kilns are available in a variety of sizes and styles, making it simple to find one that meets your requirements and budget.
- Because of their convenience, energy efficiency, and precise temperature control, electric kilns are a popular choice for pottery making.
Advantages Of Wood Fired Kilns
Wood kiln firing is a traditional method of firing pottery and other ceramics that employs the use of a wood-fired kiln to achieve and maintain the required firing temperature. The heat from the burning wood is used to fire the ceramics in wood-fired kilns, which are typically fueled by wood logs or wood chips.
One of the primary benefits of wood kiln firing is that it allows potters to achieve effects on their work that are not possible with other firing methods. Wood ash, for example, can fall onto the ceramics during firing, creating a natural glaze or pattern. Potters can also experiment with different types of wood to achieve different effects, such as using oak to create a more neutral finish or fruit woods to add color to the ceramics.
Another advantage of using a wood kiln is that it is low-tech and can be done on a small scale, making it accessible to potters who may not have access to more expensive or complex firing equipment.
Overall, wood kiln firing is a popular choice for potters who want to create one-of-a-kind pieces and who enjoy the traditional, hands-on approach to pottery making.
How Beehive Kilns Revolutionize Ceramics
A beehive kiln is a type of kiln that was developed in the nineteenth century and is distinguished by its dome-shaped design that resembles the shape of a beehive. Originally used to make bricks and tiles, beehive kilns have also been used to fire ceramics and other materials.
Beehive kilns were more efficient and produced a more consistent product than other kilns at the time, which revolutionized ceramics production. The kiln’s dome-shaped design allowed for more even heat distribution, resulting in more evenly fired ceramics. The dome shape of beehive kilns allowed for more efficient heat retention and combustion, making them more fuel-efficient than other kilns.
Aside from their efficiency and consistency, beehive kilns were also easier and less expensive to build than other types of kilns, making them more accessible to a broader range of potters and ceramics producers. As a result, beehive kilns played an important role in the expansion of ceramics production in the nineteenth and early twentieth centuries.
Advancements In Kiln Technology
In recent decades, kiln technology has seen a number of advancements, including the development of more efficient and precise heating systems, improved insulation materials, and the use of computerized controllers. Some of the more recent technologies that are now available are that I am aware of as of this writing:
- Microwave kilns: These kilns, known for their speed and efficiency, use microwave energy to fire ceramics and glass.
- Solar kilns: These kilns use solar energy to fire ceramics and are a more environmentally friendly and sustainable alternative to traditional kilns.
- Vacuum kilns: Vacuum kilns use a vacuum to remove air from the kiln chamber, allowing for more precise control over the firing process and producing stronger, more durable ceramics.
- Digital kilns: Digital kilns have computerized controllers that allow potters to remotely set and monitor the firing temperature and schedule.
- 3D printing kilns: These kilns are designed specifically to fire 3D printed objects and are typically used in the production of ceramic or glass products.
Overall, these newer technologies give potters and other ceramics artists more options and more precise control over the firing process, which can lead to higher quality products and more efficient production.
The Evolution and Science Behind Kilns
Historical Context
Kilns have been an integral part of human civilization for thousands of years. The earliest kilns date back to the Neolithic period, around 6000 BCE, where they were used for pottery and brick-making. Over the centuries, kilns have evolved in design and purpose, from simple pit kilns to highly sophisticated electric kilns. The Romans, for instance, were known for their advanced kiln designs, which contributed to their architectural marvels. In Asia, kilns played a crucial role in the development of porcelain, a significant cultural export.
Scientific Principles
The operation of a kiln is based on the principles of thermodynamics and material science. Here are some key scientific aspects:
- Heat Transfer: Kilns operate on the principles of conduction, convection, and radiation to transfer heat to the material inside.
- Chemical Reactions: During the firing process, various chemical reactions occur, such as oxidation or reduction, affecting the final product’s properties.
- Phase Transitions: Materials like clay undergo phase transitions at specific temperatures, altering their molecular structure and hence their physical properties.
- Thermal Efficiency: Modern kilns are designed to be thermally efficient, minimizing heat loss through insulation and advanced materials.
- Control Systems: Advanced kilns use digital control systems to regulate temperature, ensuring uniform heat distribution and precise firing cycles.
I say by understanding the historical context and scientific principles behind kilns, we can appreciate their complexity and the advancements that have been made in their design and operation over the years.
Safety Tips When Using A Kiln
According to Lindsay Oesterritter, Here are some additional safety tips for around the kiln when the fire is burning:
- Keep long hair pulled back and scarves tucked in.
- Always have a bottle of drinking water nearby.
- Wear leather gloves and or welding gloves when stoking the fire.
- If there is an axe or splitting axe on site, make sure it is sheathed and/or stored out of the way when not in use.
- Do not leave the hand torch (and/or other fire starters) by the kiln during the firing.
- Do not look at a red hot kiln without welding glasses.
- Particulate masks that help with smoke inhalation are P100 and N95.
- Live embers should only be stored in galvanized metal; never vacuum them. It is best to quench them with water after the firing is unloaded, if they are in an open pit
- Have adequate light for nighttime firing.
- Have a first aid kit on hand.
- Have a fire extinguisher and a water hose (when possible) on hand.
- Communicate with anyone that is firing with you when you are lifting a lid or adding to the fire3.
Lindsay Oesterritter is the director of Objective Clay, co-founder and organizer of National Clay Week, and a full-time studio potter. Lindsay earned her MFA from Utah State University in Logan, Utah, held the position of Assistant Professor of Ceramics at Western Kentucky University (2009–2015), and earned Associate Professor in 2015. Lindsay was a resident artist at Arrowmont School of Arts and Crafts in Gatlinburg and in Australia at Strathnairn Arts Association. She lectures and exhibits nationally and internationally, most frequently on wood firing techniques and kiln construction/design, and is continually inspired by the craft community. View her work and workshop schedule at: loceramics.com
Glossary of Technical Terms
| Term | Definition |
|---|---|
| Kiln | A furnace or oven used for burning, drying, or hardening materials, especially clay and ceramics. |
| Firing | The process of heating materials in a kiln. |
| Ceramic | A hard, brittle material made by firing clay or a mixture of minerals. |
| Temperature Zones | Different areas within a kiln that maintain specific temperatures. |
| Pyrometer | An instrument for measuring high temperatures, commonly used in kilns. |
| Cones | Pyrometric cones used to measure heatwork during the firing process. |
| Heatwork | The combined effect of time and temperature on ceramic ware during firing. |
| Glaze | A glassy coating applied to ceramics before firing for decoration and protection. |
| Bisque Firing | The first firing process for ceramics, intended to harden the clay before glazing. |
| Glaze Firing | The second firing process, intended to melt the glaze onto the ceramic piece. |
| Venting | The process of allowing gases to escape from the kiln during firing. |
| Thermal Shock | Rapid temperature change that can cause materials to crack. |
| Flue | A duct or passage for waste gases to escape from the kiln. |
| Insulation | Material used to reduce heat loss from the kiln. |
| Quartz Inversion | A phase change in quartz that occurs at specific temperatures, affecting the firing process. |
About the Author: Ed Shears
Hello, I’m Ed Shears, the creative force behind Artabys.com, a platform dedicated to promoting visual arts education and awareness. With a robust foundation in traditional pottery techniques, my true passion lies in creating unique ceramic wall art. Each piece I create is handbuilt with meticulous attention to detail, embodying originality and craftsmanship.
Credentials and Experience
- Education: A dedicated student of ceramic arts, my skills have been honed through rigorous training and hands-on experience.
- Artistic Philosophy: I believe in the unparalleled beauty of handcrafted original artwork, which not only adds a unique touch to living spaces but also resonates with the soulful touch of its creator.
- Achievements: I am a renowned author and contributor at Academia.edu and have showcased my artwork at Fine Art America since 2015.
For more about me and my work, feel free to visit my full artist page.
Frequently Asked Questions (FAQ) on “What Is A Kiln Used For?”
Q: Why do you need to use a kiln?
A: A kiln is essential for several processes like drying, hardening, or firing various materials. It provides a controlled environment where temperature, humidity, and air circulation can be regulated to achieve the desired outcome, such as hardening pottery or drying lumber.
Q: What are the 3 main types of kilns?
A: The three main types of kilns are:
- Pottery Kilns: Used for firing ceramics and pottery.
- Glass Kilns: Specifically designed for glass fusing, slumping, and annealing.
- Industrial Kilns: Used in manufacturing for processes like calcining limestone or drying wood.
Q: What is a kiln used for in art?
A: In art, kilns are primarily used for firing ceramics, pottery, and glass art. They help in hardening clay sculptures, setting glazes, and fusing glass pieces to create intricate designs.
Q: Is a kiln just an oven?
A: While both a kiln and an oven are heating devices, they serve different purposes. An oven is generally used for cooking and baking at lower temperatures, whereas a kiln operates at much higher temperatures and is used for processes like firing ceramics, drying wood, or smelting metal.
Q: How does a kiln work?
A: A kiln works by creating a controlled environment where the temperature can be steadily increased to the desired level. It uses heating elements or burners to generate heat and may have vents for air circulation and gas release.
Q: Can you make your own kiln?
A: Yes, it’s possible to build your own kiln, although it requires some expertise in construction and a good understanding of the heating elements involved. DIY kilns are often made for small-scale projects and may not offer the same level of control as commercial kilns.
Q: What materials can be fired in a kiln?
A: Common materials that can be fired in a kiln include clay, ceramics, glass, and certain metals. The type of material dictates the firing temperature and duration.
Q: Is it safe to use a kiln at home?
A: Using a kiln at home is generally safe as long as you follow all safety guidelines, such as proper ventilation, keeping flammable materials away, and using protective gear.
Take The Kiln Quiz For Fun!
References
Watkins, J. C., & Wandless, P. A. (2004). Alternative Kilns & Firing Techniques: Raku, Saggar, Pit, Barrel. Lark Books. https://books.google.com/books?hl=en&lr=&id=eMeEnoQ4shgC&oi=fnd&pg=PP8&dq=electric+kilns&ots=3VFndN_zwv&sig=wNwlO7ncIVZlonQrnVJKsdcYFwE#v=onepage&q=electric%20kilns&f=false
Hasaki, E. (2002). Ceramic kilns in ancient greece: technology and organization of ceramic workshops. University of Cincinnati. https://www.proquest.com/openview/45077bed6272a9b32a72ed54b7bb434b/1?pq-origsite=gscholar&cbl=18750&diss=y
Fraser, H. (2000). The electric kiln. University of Pennsylvania Press. https://books.google.com/books?hl=en&lr=&id=sBIQ1bRVe3IC&oi=fnd&pg=PA7&dq=electric+kilns&ots=_iQ02M9eos&sig=7Zw643POWTMnFZ6otn5T4kwmWdQ#v=onepage&q=electric%20kilns&f=false
Footnotes
- Norsker, Henrik. The Self-reliant potter: refractories and kilns. F. Vieweg, 1987. ↩︎
- Minogue, Coll., Sanderson, Robert. Wood-fired Ceramics: Contemporary Practices. United Kingdom: University of Pennsylvania Press, Incorporated, 2000. ↩︎
- Oesterritter, Lindsay. Mastering Kilns and Firing: Raku, Pit and Barrel, Wood Firing, and More. United States: Quarry Books, 2019. ↩︎
