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Kiln Firing Chart for Pottery and Ceramics [Infographic]

Kiln firing chart blog header

When it comes to firing ceramics, different types of clays and glazes are rated for different temperatures. A kiln firing chart, also known as a cone firing chart, is a useful tool for understanding the effects of temperature on different types of clays and glazes, as well as determining what firing schedule setpoints should be used depending on the cone rating of the media you’re firing.

What Temperature Is Pottery Fired At? Understanding Different Types of Ceramics

What temperature is pottery fired at? Well, that depends. There a three main types of clay that are used to make pottery: earthenware, stoneware, and porcelain. Each of these has different temperature requirements, as well as different properties once fired.

1. Earthenware

Earthenware clay is the most common type of clay used in ceramic firing today. Earthenware is softer than the other types of clay, making it easier to work with and more forgiving. Earthenware also has the lowest firing temperature requirements, which is why it was the first type of clay used to make pottery during the early stages of kiln history.

A collection of fired earthenware pottery to demonstrate the qualities of fired earthenware
Fired earthenware is porous and relatively soft. Earthenware ranges from white and gray hues to browns, oranges, and reds.

 

Firing Temperature

Earthenware clay typically reaches maturity (or optimum hardness) between 1745° F and 2012° F, although some low-firing earthenware clays can be fired in temperatures as low as 1200° F.

Cone Rating

Earthenware is what’s known as a “low fire” clay. Earthenware clay can be fired from Cone 015 up to Cone 1, but Cone 04 is the average.

Physical Properties

Since earthenware is fired at lower temperatures, it typically remains porous, relatively soft (you can scratch it with a knife!), and still absorbs water. Glazes are often required to make earthenware harder and watertight.

2. Stoneware

Stoneware is a “mid-range” or “high fire” clay that requires higher firing temperatures and a longer firing schedule than earthenware. Once it has been fired, stoneware is hard, dense, and rocklike – hence the name!

A collection of fired stoneware ceramics, demonstrating its hard, rocklike texture
Named for its hard, rock-like texture, fired stoneware is often gray or brown.

 

Firing Temperature

Stoneware reaches maturity between 2000° F and 2400° F – hotter than lava!

Cone Rating

Stoneware is typically fired between Cone 2 all the way up to Cone 12, with Cones 7 and 10 being the most common for mid-range stoneware and high fire stoneware, respectively.

Physical Properties

Since stoneware is fired at higher temperatures, it has time to fully vitrify, or form a glassy, nonporous bond on its surface. Finished stoneware is durable, hard, and nonporous. Unlike earthenware, stoneware is waterproof once fired even without the use of glazes.

3. Porcelain

Originating in China in 1600 BC, porcelain is a “high fire” clay that produces extremely hard, shiny, often white or translucent ceramics. Also known as kaolin clay (named after Kao-ling hill in China, where it was mined for centuries), raw porcelain is extremely dense and difficult to work. Often, porcelain is mixed with other types of clay to improve its workability.

A collection of fired porcelain ceramics, demonstrating its hard, glasslike white exterior
Fired porcelain is hard, smooth, and glasslike – notable for its white or translucent color

 

Firing Temperature

Porcelain typically reaches maturity between 2381° F and 2455° F – however, pure kaolin reaches maturity at 3272° F!

Cone Rating

Porcelain clay is fired between Cone 10 and Cone 13.

Physical Properties

Once fired, porcelain is extremely hard and fully vitrified, making it watertight and non-absorbent. Porcelain is noted for its distinct white color.

Understanding Firing Cone Ratings

As we mentioned earlier, different ceramic materials and glazes have a cone rating. Firing cones, or pyrometric cones, are a simple pyrometric device that indicate kiln temperature. Firing cones melt when exposed to a certain temperature for a prolonged period of time. Different ceramics and glazes are given a cone rating to indicate the temperatures at which they’ll reach maturity.

Firing cones range from 022 to 14, with 022 being the lowest temperature and 14 being the highest. As you’ll see on the kiln firing chart below, when a firing cone rating has a ‘0’ in front of it, a lower number indicates a higher fire temperature.

However, for firing cones without a ‘0’ in front of their rating, higher numbers indicate higher firing temperatures.

Kiln Firing Chart [Infographic]

In the kiln firing chart below, you’ll be able to see which temperatures correspond with various cone ratings and materials. The color gradient indicates the incandescence of the kiln at various temperatures, and the column to right indicates how the physical properties of ceramic changes at each temperature.

A pottery kiln firing chart, with temperature labels for each cones as well as insights for what changes occur in the clay at various temperatures.

Download PDF!

Reach the Right Setpoints on Your Kiln Firing Chart with Ease and Precision

The TAP and TAP II Controllers by SDS Industries are the most advanced, precise, and easy-to-use pottery kiln controllers on the market today. With responsive touchscreen controls, an intuitive graphical UI, and integration with the TAP Kiln Controller Mobile App, TAP Kiln Controllers can pair with any relay-controlled kiln or oven to allow you to easily manage and execute your kiln firing schedules.

We invite you to explore our selection of digital kiln controller, standalones, and conversion kits on our online store. You can also purchase TAP Digital Controllers or TAP-Controlled Kilns and Heat Treat Ovens through one of the following distributors:

CTA to shop pages for pottery kiln temperature controllers.

 

Shop Pottery Kiln Temperature Controllers
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Pros and Cons: Automatic Kiln Controllers vs Manual Kiln Controllers [Infographic]

Header image for blog post on manual kiln controllers vs automatic kiln controllers.

Just like with cars, artists and hobbyists have two options when it comes to kiln controllers: manual and automatic.

Manual kiln controllers rely completely on user input. With a combination of analog dials and switches, users have to set the temperature of their kiln, adjust temp throughout the firing process, and make sure they keep track of their firing schedule (and don’t forget to turn off their kiln!).

Automatic kiln controllers, on the other hand, significantly streamline the firing process by managing the temperature of the kiln without user input. Also known as digital controllers, automatic kiln controllers allow users to program their device to reach the right temperatures at the right times without their direct oversight.

Both types of controllers have their pros and cons – so which one is right for you?

Infographic: Automatic Kiln Controllers vs Manual Kiln Controllers

Below is a quick summary of the pros and cons of automatic and manual controllers. Later on, we’ll be exploring these differences more in-depth!

Infographic explaining the pros and cons of manual kiln controllers and automatic kiln controllers

Download the PDF!

Manual Kiln Controllers: Pros and Cons

Just like with cars, manual controllers have an element of old school cool. Ceramists, glassworkers, and metal workers have been managing their firing process by hand for almost 10,000 years! However, while manual kiln controllers are more hands-on, unlike manual cars they don’t offer more control – just a greater need for hands-on management. Like manual cars, they also have a much smaller margin for error.

However, manual kiln controllers do have several advantages. They are extremely easy to pick up and use – the learning curve for managing inputs is minimal (it’s just like using your oven!). They tend to be significantly cheaper than automatic kiln controllers. And they do help you feel more viscerally connected to the firing process. After all, you’ll hardly be able to leave your kiln!

If that sounds up your alley, you do want to be aware of the potential downsides. While it’s easy to manage settings on manual controllers, achieving desired results is much more difficult. If you lose track of time, or don’t monitor temperature, it’s easy to ruin the ceramic or metal piece or glasswork you’ve been working on for hours.

Pros of Manual Kiln Controllers

  • Simple controls.
  • Gives you more opportunities for direct observation of the outcomes for each stage of the firing process.
  • More hands-on – so you feel involved in the firing process.
  • Less expensive.
  • Available on most entry level kilns (although you can always convert to automatic later!)

Cons of Manual Kiln Controllers

  • Time intensive and requires constant attention.
  • Very little margin for error – extremely minor missteps can result in inconsistencies or failed firings.
  • Diagnostics are limited to firsthand observation and the use of tools like thermocouples and pyrometers.
  • Unable to save firing programs – so you have to recreate your firing process from scratch every time.

Automatic Kiln Controllers: Pros and Cons

Automatic kiln controllers, on the other hand, do a lot of the heavy lifting for you. After programming your firing schedule or choosing from a preset, automatic controllers manage your firing process – monitoring the temperature of the various zones of your kiln and adjusting temperature throughout the stages of your firing process. 

This allows for a greater degree of precision, making them ideal for glass firing or other complex processes that rely on gradual changes to temperature and the ability to set ramps and holds. Additionally, some digital controllers, such as TAP Kiln Controllers, have tons of quality-of-life features that significantly streamline and simplify the kiln firing process – like easy-to-use, responsive touchscreen controls, mobile apps that send you alerts and push notifications and allow you to adjust your settings remotely, and the ability to save an almost infinite number of preset firing schedules.

Automatic kiln controllers can also provide diagnostic reports and alerts for preventative maintenance, letting you know when different components of your kiln are approaching the end of their life.

However, that is not to say that automatic kiln controllers aren’t without their drawbacks. They tend to be a little more expensive than manual controllers, and they might not be available out-the-box on every kiln model. Additionally, many automatic controllers have cumbersome controls and extremely steep learning curves that leave users pouring over user manuals and hoping they’re entering the correct inputs. (In fact, our own frustrations with existing automatic kiln controllers led us to create SDS Industries. We wanted kiln control to be more intuitive, streamlined, and user friendly!).

Pros of Automatic Kiln Controllers

  • Manages most of the firing process for you – eliminating user error or the need for constant oversight.
  • Allows for more precision and the ability to execute complex firing processes like ramps/holding and annealing for glasswork.
  • Provides more predictability and ensures consistency for the finished product(s).
  • Gives users the ability to save presets for firing schedules they frequently use.
  • Provides diagnostics and alerts for preventative maintenances.
  • Allow users to remotely monitor their firing and make any necessary adjustments.

Cons of Automatic Kiln Controllers

  • More expensive.
  • Some automatic controllers have complicated, unintuitive controls and steep learning curve.
  • Don’t come standard on all kiln models.

Is an Automatic Kiln Controller Right for You?

Hopefully, this article gave you a clear idea of the pros and cons of manual and automatic kiln controllers – and also gave you ideas about what type of controller might work best for you. If you are considering purchasing an automatic kiln controller, we invite you to explore our suite of TAP Controllers. TAP Controllers utilize the most advanced automatic kiln control technology available – to provide you with precision, convenience, and ease-of-use. So that you have more time to focus on your craft, without having to stress over the mechanics of temperature control!

Modernize Your Kiln Firing with TAP Controllers

Check Out TAP Kiln Controller Products!