Guide to Kiln Temperature Ranges for Pottery

Are you concerned about achieving the perfect color for your pottery during firing or struggling to get the results you’d like?

Firing is the most critical stage of the ceramic-making process, and though it takes far less creative energy than the previous stages, it certainly requires a level of know-how that isn’t typically innate.

Our Best Ceramic Kilns for Home Use

Great Starter for Home Studio	Jen-Ken AF3C 11/9 Ceramic Kiln Can be used with a standard home outlet for an easy fit for any new home studio. Affordable option for professionals who are firing many smaller pieces Best for low-fire clays and mid- to high-fire stoneware	$907.99 View Product
Perfect for Firing Bigger Pieces	Jen-Ken Ceram-a-Glass AF3P 1815 Ceramic and Glass Kiln More advanced capabilities of firing both clay and glass projects of bigger size Unique in its ability to fire both glass and ceramic projects Due to the 240 voltage and high amp requirement, you may have to install a new breaker	$1,431.99 View Product
Most Popular Size Available	Evenheat Ceramic Kiln - RM II 2322 Easily fire larger amounts of bigger pieces like pots, plates, and bowls Benefits of increased size and more versatile capabilities make it worth the increase in price. Due to the 240 voltage and high amp requirement, you may have to install a new breaker	$2,935.00 View Product

All clays and glazes are created to mature at specific temperatures, and any variance can lead to unsatisfactory results in ceramic durability or color. If fired too high, clay can deform or even melt and can result in glaze runoff; if fired too low, your pieces will be dry, rough, and potentially unsolidified.

In order to help you achieve the best possible results with your kiln, we’ve put together this guide describing the temperatures at which to fire each clay body and type of glaze. Below are our suggestions categorized by temperature, from lowest to highest, and the most important details you’ll want to know when firing each ceramic material and glaze.

Low-fire

Historically, low-fire has been the most commonly used firing range due to limitations in kiln technology. Though kilns are now capable of much more complex, high-temperature processes, the low-fire range continues to be popular due to the fact that it allows ceramic artists to use a variety of colorants that either burn off or become unstable at higher temperatures. Here are the important details to note about low-fire materials and glazes:

Clay body type

The most common low-fire clay body is earthenware, which is highly plastic (easily worked) and typically won’t shrink, warp, or sag excessively. Terracotta is one of the most popular types of earthenware.

Temperature range

Earthenware contains iron and other minerals which cause it to reach optimum hardness between 1745℉ (950℃) and 2012℉ (1100℃). The average firing temperature at which low-fire materials reach maturity is 1940℉ (1060℃).

Cone range

While Cone 04 is the average when firing earthenware, low-fire materials can be fired anywhere from Cone 015 up to Cone 1.

Kiln color

Yellow-orange

Firing results

Since earthenware is softer than other clay bodies, it seldom becomes fully vitrified, meaning it will be porous, absorb liquids, and be less durable. A separate glaze layer will also be apparent. The color of low-fire clays after emerging from the kiln depends largely on the content of mineral impurities in the clay, but they can become brown, red, orange, buff, medium grey, or white after firing.

Low-fire glazes

In general, low-fire glaze colors are more varied and brighter than mid- or high-fire glazes, but they can appear rather harsh and raw-looking. Fired even lower than their clay bodies, very low-fire glazes, like luster glazes (metallics, iridescents) and overglaze enamels, are often applied after a higher-fire glaze firing, and are best suited for firing between Cone 018 and Cone 016. A burnished low fire clay bisque for sawdust firing also occurs within this range.

The best results for most low-fire red and orange glazes happen at Cone 07 or lower, and many low-fire commercial glazes will be most successful between Cone 06 and Cone 04.

Kiln Options

Most kiln manufacturers don't produce kilns that do low-firing exclusively, and instead produce mid-range or high-fire kilns which of course can support the lower temperatures.

Please continue to read below to see what your options are with these!

Mid-range

With the increased availability of electric kilns, mid-range firing has increased in popularity among potters, especially as artists become more concerned about energy and fuel usage. Most electric kilns can comfortably reach this range without severely decreasing their lifespan or that of their elements.

Below are some details about the clay bodies, suggested temperatures, and glazes intended for mid-range firing:

Clay body type

Typically, mid-range clay is stoneware, a plastic clay that is often grey when moist. Getting its name from the dense, rock-like nature of the clay body when fired, stoneware is typically combined with other clays to modify it, such as ball clays which might be added for plasticity. It is important to note that stoneware is divided into two types - mid-fire and high-fire - and this section of the guide will be referring specifically to mid-fire stoneware.

Temperature range

For mid-range material, a kiln should be firing at a temperature between 2124℉ and 2264℉ (1162-1240℃). This is the most common temperature range for industrial ceramics.

Cone range

Mid-fire earthenware should be fired between Cone 2 and Cone 7.

Kiln color

Mostly yellow with a hint of orange.

Firing results

Like low-fire bodies, mid-range stoneware is relatively soft and porous and has a clearly separate glaze layer after firing. However, a mid-range firing results in increased durability of the ware as well. When fired, stoneware ranges in color from light grey to buff, to medium grey and brown.

Mid-range glazes

Mid-range glazes typically mature between Cone 4 and Cone 6, and most commercial underglazes have a maximum temperature of Cone 6. These glazes are more durable, still offer a fairly extensive color range, and though not quite as harsh as low-fire glazes, can still be quite bright.

Kiln Options

We offer a variety of mid-range firing kilns at Soul Ceramics. All of these kilns will reach at least Cone 8 / 2300 °F and will be perfect for your high firing kilns.

If you're looking for a small sized mid-range firing kiln, we'd recommend the Evenheat RM II 1413.

If you're looking for a medium sized mid-range firing kiln, we'd recommend the Evenheat RM II 2322.

If you're looking for a large sized mid-range firing kiln, we'd recommend the Evenheat RM II 2929.

If you don't quite need to reach Cone 8 / 2300 °F - The Evenheat RM 2522 and Evenheat RM 2541 are two of our favorite choices for large mid-range kilns and will reach Cone 03 / 2000 °F.

High-fire Stoneware

Though some stoneware is intended for mid-range firings, other types of stoneware mature at higher temperatures and result in a different ceramic end product. Glazes intended for high-fire procedures are also quite different.

In order to understand how best to fire high-fire stoneware and glazes, here are some tips on their temperature requirements and composition:

Clay body type

High-fire stoneware is very similar to mid-fire stoneware in terms of ingredients, and may similarly be modified through adding other types of clay bodies (such as fire clays, which raise the maturation temperature). However, high-range bodies have either more refractory elements than mid-range stoneware clays, less fluxing agents, or a combination of the two.

Temperature range

The average firing temperature for high-fire stoneware is 2381℉ (1305℃). However, anywhere from 2305℉ to 2336℉ (1263℃ to 1326℃) may be appropriate depending on the specific clay used and desired effect.

Cone range

Between the range of Cone 8 and Cone 12, high-fire stoneware will mature. Cone 10 is the average for this clay body.

Kiln color

Yellow

Firing results

When fired, high-fire stoneware becomes hard, vitrified, and non-absorbent. It is extremely durable, especially compared to both low-fire and mid-range ceramics. Additionally, a body-glaze layer will form between the clay body and the glaze, and though firing color will vary, depending on the process, the finished product can be light grey, buff, medium grey, or brown.

High-fire glazes

Glazes intended for high-fire clays are fired in the same cone and temperature range as the clay body of this category. Like stoneware, they are also dense and durable.

However, the color range is limited due to the varying effects of oxidation and reduction on glaze colorants. Though there are still a few coloring oxides in this high temperature range that can produce a rich color, the palette is much more limited.

Kiln Options

We offer a variety of high fire kilns at Soul Ceramics. All of these kilns will reach at least Cone 10 / 2350 °F and will be perfect for your high firing kilns.

If you're looking for a small high fire kiln, we'd recommend the Evenheat HF 1413.

If you're looking for a medium sized high fire kiln, we'd recommend the Evenheat HF 2318

And if you're ready to get some real work done with a large sized high fire kiln, we'd recommend the Evenheat HF 2927!

High-fire Porcelain

The clay bodies that require the highest firing temperatures are kaolin clays, which are most commonly used for porcelain. Though porcelain has similar requirements to other high-fire clays, here are some of the important differences you’ll want to note if using this ceramic material:

Clay body type

Named after a hill in China from which it was mined for centuries, kaolin is the purest form of clay and is the foundation of all porcelain clay bodies. Though pure kaolin clays can be fired, often they are mixed with other clays to increase both workability and lower the firing temperature, so if using a kaolin-based clay body, be sure to note how pure your material is, as this will change the required temperature.

As a clay body, porcelain is known for its hardness, extremely tight density, whiteness, and translucence in thin-walled pieces. Another difficulty with porcelain bodies is that they are very prone to warping during drying in the kiln.

Temperature range

While pure kaolin fires to maturity at 3272℉ (1800℃), most porcelain should be fired between 2381℉ and 2455℉ (1305℃ and 1346℃) for best results.

Cone range

The acceptable cone range to ensure porcelain clays mature is between Cone 10 and Cone 13.

Kiln color

White

Firing results

When fired, porcelain becomes a hard, vitrified, non-absorbent clay body, very similar to high-fire stoneware. It also develops a body-glaze layer formed between the clay body and the glaze. The absence of any iron, alkalies, or alkaline earths in the molecular structure of kaolin not only dictate its high-fire requirements, but are also responsible for its most identifiable characteristic: its white color.

When fired, the color of porcelain ranges from a very light grey or buff to near-white and white.

Porcelain glazes

Similar to high-fire stoneware, glazes used for porcelain are limited in color variety and intensity. Most glazes intended for high temperature firings will be lighter, less brilliant, and generally fewer in number and variety.

We hope this guide has been useful in helping you to determine what temperature best suits your projects! Along with this guide, be sure to always check the labels of any glaze or clay you buy in order to confirm temperature requirements. Happy firing, and if you have any questions that have yet to be answered, please don’t hesitate to contact us!