How Kilns Work in Pottery

Kilns are the tools that turn shaped clay into ceramic by controlling heat over time. While different kilns use different fuel sources, they all exist to raise clay and glaze to the temperatures needed for permanent ceramic change.

A pottery kiln works by building and holding controlled heat inside an insulated chamber so clay can dry out completely, mature into ceramic, and, when needed, melt glaze onto the surface.

This guide explains the basic kiln process, the main kiln types, and why temperature control, airflow, and cooling matter so much in pottery.

What Does a Pottery Kiln Actually Do?

A pottery kiln does much more than simply “make clay hot.” Its job is to raise temperature in a controlled way so clay can dry fully, turn into ceramic, and, when needed, bond a glaze to the surface. That control is what separates a kiln from an ordinary oven or open-fire experiment.

In practical terms, kilns are used to manage the stages of pottery that depend on measured heat, timing, and cooling. The more you understand that process, the easier it becomes to see why firing, temperature, and airflow matter so much.

The main jobs of a pottery kiln are:

• remove remaining water from shaped clay safely
• turn dried clay into harder ceramic during the bisque stage
• mature the clay body to the range it was designed for
• melt or mature glaze during glaze firing
• help produce specific surface results depending on kiln type, atmosphere, and schedule

Potters also talk about kilns in connection with cones, kiln design, and firing range because the kiln is really the control center for the whole heat process, not just a box that happens to get hot.

How Is Pottery Fired in a Kiln?

Pottery firing is the controlled heating of clay inside a kiln so the piece can move from dry clay to ceramic. In most beginner workflows, that happens in two stages: a bisque firing first, then a glaze firing later if the piece will be glazed.

The firing process is not just about reaching a hot number. It also depends on how quickly the kiln heats, how dry the ware is before loading, whether the clay and glaze match the target range, and how the kiln cools afterward.

For more reliable firing results:

• fire only pieces that are fully dry
• use cones or another reliable way to confirm heatwork
• keep shelves protected and clean
• bisque fire slowly enough for moisture to escape safely
• match your clay and glaze to the same firing range

If you are still learning the temperature side of firing, this article pairs naturally with our guide to kiln temperatures in pottery.

What Are the 3 Main Types of Pottery Kilns?

There are 3 types of kilns that are most commonly used: electric, gas, and wood.

Electric kilns are the ones that are most used in pottery. This is due to the fact that these modern kilns are fairly easy to use. They have digital panels and have the option to set up your firing schedule. Not all electric kilns have digital panels. For example, Kiln Sitter has a device that controls the temperature and will switch off at a particular one. They are called semi-automatic kilns.

Electric kilns come in different sizes. There are small electric kilns that are specifically made for making jewelry and others that are bigger. Depending on the size they require more or less the same technology in order to work.

• 

• 

• 

The second type of kiln is gas kilns. Gas kilns are fuel-burning kilns. They use a gas flame to increase the temperature in the kiln chamber. You can use different types of gas to heat up the chamber. Most common for using is the natural gas from a mains supply. Some use butane or propane, which are known as bottled gases.

Just like the electric kilns the gas kilns also have different sizes. The size can vary from a 2 cubic feet kiln to a huge kiln sized as a whole room. The advantage of using natural gas is the soft flame which means that you can control the direction of the flame. The heat depends on the design of the kiln. The only disadvantage is that gas kilns must have a chimney that will be an exit point of the smoke. Gas kilns are mostly used for creating one-of-a-kind creations.

The third type is the wood-burning kiln. These kinds of kilns are built by hand. They have different shapes and sizes. One design that is common for all wood-burning kilns is the chamber because often is built as a long arch-shaped brick. This must be big enough for you to stand up in it. Just as the gas kilns wood-burning kilns also have a chimney on the back which is built with bricks.

Wood burning kilns are not often used and are most difficult to use, because you can’t control the heat and it is pretty hard to target the right temperature. It requires a lot of attention and to be fed with a lot of wood the whole day. Also, the firing is much longer than with the previous two types.

So depending on what pottery you need choose the right kiln. Have in mind that natural gas produces short and soft flames while wood produces long flames. Although by using wood-burning kilns you can create interesting and unique patterns when the flames collide with the pottery. This can be a key factor for the final product.

How Did Old Kilns Work?

Some of the oldest types of kilns are pit firing and sawdust kilns. They are both made of metal barrels, which is not primitive material. The old kilns work with an original firing technique that dates back to 800AD. Old kilns are still very popular for firing clay, although they are not as efficient as the new ones. The goal is the same and that is to fire clay.

Pit firing works with placing ware in a pit in the ground on top of some combustible materials. After the whole pit is covered you can set the fire and leave it to burn until all combustible materials are consumed by the flame.

The technique in sawdust kiln is similar to pit firing. Just like the pit firing, the ceramic ware that needs to be fired is buried in the combustible materials, which is sawdust. Then the kiln fires until all the sawdust has burned down.

How Hot Does a Pottery Kiln Get?

The temperature on the kiln depends on the pottery you are creating and what are you aiming to achieve. The average kiln can reach temperatures of up to 1100C, but these high temperatures won’t damage the kiln and what is inside of it.

A preliminary firing which is called biscuit firing goes up to 950C. This is used for making safer glazing and to make the clay firm.

Earthenware firing contains iron and other minerals that are used for lower temperature clay that will not tolerate higher temperatures without melting etc., but which allows bright colors, though it remains porous and is fairly easily chipped, goes to about 1000–1100C.

For high-fire stoneware and porcelain which must become non-porous, you need temperatures that go up to 1340C in order for you to achieve the desired product. The higher the temperature the more translucent the porcelain will become.

How Much Do Kilns Cost?

As we said before kilns come in different sizes and shapes, so the price will vary depending on these factors. You have small kilns with a price range from 750 dollars and up to 1200 dollars. On the other hand, you have bigger kilns with a price range from 3500$-4500$, which are well equipped with a lot of features.

Also, the price depends on the electric charge and power consumption. These are just a couple of factors that have an impact on the price. So, before buying we strongly suggest for you to make a quick research and to know what you need the kiln for.