How To Make A DIY Kiln

How to Make DIY Kilns

One way of firing pottery at home is to make your own, do-it-yourself kiln.

A small homemade kiln can be economical and easy to build, and if planned and done correctly, a great solution for home pottery enthusiasts.

There are many considerations to take into account before you build a kiln.

Building a DIY kiln can be a cost saver or a major expenditure depending on how you accomplish the task.

So, take the steps to make sure that you will be happy with your project for years to come.

If you are an active potter or like to take on multiple projects, you may even decide you need more than one kiln.

Although it may seem like a daunting task, making a kiln at home is quite possible.

We considered many styles and looked at the options and found a couple of the simplest ways you could put one together.

Wouldn’t that make a great weekend project with the kids?

And ideal if you have children interested in learning pottery and firing their own clay creations. 

Let’s take a look at what you will need to know, and how to put it together.

What exactly is a kiln?

Wood Fired Kiln

Kilns have been used for millennia to turn objects made from clay into pottery, tiles, and bricks.

A kiln is a thermally insulated chamber or special kind of oven for firing things like pottery and bricks, that produces temperatures sufficient to complete some process, such as hardening, drying, or chemical changes to a clay material.

A ceramic artist might use a kiln once a week to fire the bowls they have made from clay.

Some kilns look more like furnaces than ovens, and they reach temperatures far beyond regular household ovens.

Pit fired pottery was produced for thousands of years before the earliest known kiln, which dates to around 6000 BC.

The earliest kilns were simple pits in the ground into which potters placed their pots.

Early potters would cover the pots with combustible materials such as sawdust, dried manure and brush or straw, then light the whole pile on fire and leave it to burn.

In the broadest terms, there are two types of kilns: intermittent and continuous, both being an insulated box with controlled inner temperature and atmosphere.

A continuous kiln, sometimes called a tunnel kiln, is long with only the central portion directly heated.

From the cool entrance, ware is slowly moved through the kiln, and its temperature is increased steadily as it approaches the central, hottest part of the kiln.

As it continues through the kiln, the temperature is reduced until the ware exits the kiln nearly at room temperature.

A continuous kiln is energy-efficient because heat given off during cooling is recycled to pre-heat the incoming ware.

In some designs, the ware is left in one place, while the heating zone moves across it.

In the intermittent kiln, the ware is placed inside the kiln, the kiln is closed, and the internal temperature is increased according to a schedule.

After the firing is completed, both the kiln and the ware are cooled. The ware is removed, the kiln is cleaned and the next cycle begins.

Modern kilns

Modern Kiln

With the industrial age, kilns were designed to use electricity and more refined fuels, including natural gas and propane.

Many large industrial pottery kilns use natural gas, as it is generally clean, efficient and easy to control.

Modern kilns can be fitted with computerized controls allowing for fine adjustments during the firing.

Computerized controls on modern kilns allow for more specific and controlled temperature adjustment.

A user may choose to control the rate of temperature climb or ramp, hold or soak the temperature at any given point, or control the rate of cooling.

Both electric and gas kilns are common for smaller-scale production in industry and craft, handmade and sculptural work.

Why do you need a kiln?

Arranging Bricks

When considering making your own kiln at home, first think about what are your needs?

There is a multitude of questions to ponder before undertaking a DIY kiln project, to ensure you build the exact kiln for your needs. 

Some of the most relevant questions to ask yourself are: What do you need from a kiln? What size work do you produce?

Will the size of individual pieces require a kiln of a certain width or height? How much work will you produce? Will you frequently need to fire multiple pieces at a time?

What temperature range do you want to be able to fire to? Do you need a kiln that is easily capable of both oxidation and reduction atmospheres?

What atmosphere do the clay body and glazes that you want to use, require?

There are many styles of kilns available for purchase, but not all kilns are created equal.

Over the last several years, there has been a growing curiosity in pottery and many people have built out hobbyist studios in their homes.

Many beginners simply purchase the cheapest possible kiln, use it for a few years and then put dump it into storage until they decided to sell all their equipment.

Many of these cheap kilns are easily attainable, but they are not necessarily the best option.

Constructing a kiln at home, rather than purchasing a pre-made one is a great DIY project if the circumstances fit your situation.

If you are past the beginner phase and are considering advancing your pottery skills, why not build your own kiln to your exact specifications for your needs?

Types of Kilns

Improved Model Of Pit Kiln

Throughout the centuries, potters have realized that the more enclosed the primitive pit kiln became, the hotter the firing and the more durable the pottery.

They discovered the firing temperatures could be increased by banking up the sides of the pit with clay.

Pottery villages were commonly built on top of the clay source.

Utilizing the banks and hills of clay, they hollowed out holes large enough for an average-sized man to crawl into.

The main cavity was widened and then tapered back into a chimney flue leading up to the surface.

After the hole and cavity were hollowed out, the firebox, floor, and walls were shaped in the clay and allowed to dry.

A small fire of increasing intensity was built in the entrance or firebox and allowed to burn for weeks until the inside walls were bisque (which changed the clay into ceramic) transforming the chamber into a solid structure.

Other styles such as Anagamas, a narrow single-chamber kiln, are still used today in some Asian countries, along with other types of kilns.

A related form of the kiln, the Noborigama (a multiple-chambered kiln), is still commonly used in the eastern cultures and elsewhere.

Both of these styles, and any type of kiln that has a chimney on one side and the fire chamber on the other, are called cross-draft kilns.

Cross-draft kilns allow the development of special wood ash effects because the flames from the fire chamber, along with a lot of wood ash, are pulled through the pots in order to exit the chimney.

This leaves ash on the pots, and when the build-up gets thick enough, the ash melts and turns to glaze.

Another type of kiln is the downdraft kiln. The downdraft kiln originated in Germany in the 1800s and is one of the most commonly used kilns today.

The Downdraft Kiln

It is designed to use either wood or gas as the fuel source. In this type of kiln, the heat source is located below or level with the base of the firing chamber.

Flames come into the firing chamber and rise to the top of the kiln.

The heat then rolls around the top and is sucked back down through the pots and out the flue (the channel through which the smoke and fumes exit the kiln).

This is the type of kiln commonly built today. With the heat source under the firing chamber, most of the ash will stay in the fireboxes.

This type of kiln is ideal for creating clean ceramics, due to the lack of ash in the chamber.

These ceramics will almost always be fired a second time after they’ve been glazed.

History is rich with a multitude of types of kilns that were built to fit the needs of the society and utilize materials that were available and abundant such as clay. 

But before we tell you about the design and building of our DIY kiln, there are two different types of kilns common nowadays we would like to go over.

In general, there are two types of kilns used today. One type is computerized controlled and the other is manually operated.

The computerized kilns are great for controlled glaze firing cycles. They are also convenient for low maintenance bisque firings.

The manual kilns are just as good but require a lot more attention.

Most manual kilns are equipped with a device called a “kiln setter” that will shut the kiln off at the proper temperature.

Pro Tip: Regardless of what type of kiln it is, kilns should never be left unattended while firing.

How to make your own kiln at your home

Only after you have answered the above questions and laid out your needs, should you begin your planning and construction of your kiln?

Two of the most cost-efficient ways to DIY a kiln are listed below.

They are by no means the only way to build a kiln at home but they are simple and low cost and can get you firing in a short period of time.

Building a kiln at home can be a great way to fire your pottery, without needing to join a cooperative or rent space at a studio.

Keep in mind, when you are considering a home-made kiln, that they do require a fair amount of space, and can be a safety hazard if not done correctly.

When you are considering the placement of your kiln, especially if you will be building a wood-fired kiln, make sure that you do not put other structures, like your house, at risk.

Give your kiln plenty of space to get hot, and make ash. Also, remember that kilns can be a danger to pets and small children.

Make sure that you are fully aware of where kids and pets are when you are loading your kiln, and especially when you are firing the kiln.

You don’t want kids or pets to be accidentally burned by a hot kiln.

Always make sure that you have a water source close to your kiln, just in case things get out of hand.

The last thing you want to do is harm your property or that of your neighbors because your kiln went rouge.

Brick and Stove Method

Illustration Of Brick Kiln

If you can find some red bricks and an old wood stove in working order, you will be able to construct a homemade kiln.

It is easy to put together and take apart. You can build it to the dimensions you need.

When you build the brick box over the old wood stove, it will create a kiln that you can easily use to complete your pottery.

Materials you will need:

  • An old wood stove
  • Red clay bricks
  • Dry seasoned wood
  • A pipe that will fit inside the hole

Here is the four-step process:

  • Collect hard firebrick (red bricks), an ideal material to build your homemade kiln. These bricks are made of clay. Brick-made pottery kilns can withstand high heat temperatures, absorb heat and transfer it back to the pots. This results in a condition that allows the pots to be heated uniformly and for long periods of time.
  • Make a dry-stacked kiln by stacking the bricks one on top of the other without using any mortar–the kiln will be temporary, but it will still achieve more or less the same temperature as a kiln made using mortar. The dry-stacked kiln is made by placing the firebox (where the wood is kept) below and the ware chamber (where pots are placed) above it.
  • Put the pots inside the ware chamber, and stack more bricks at the top to create a roof. Build a brick chimney or make a hole at one end, so that you can insert a pipe into the hole. This will draw the heat and smoke through the fireplace and away from the kiln for uniform and effective heating.
  • Make a small fire to fire up the kiln. For the fire, collect dry seasoned wood that can burn at a very high temperature. Use a newspaper if necessary, to help start the wood fire. Don’t heat the kiln too fast otherwise, your clay pieces will crack or explode. It can take about two hours or more to feed the fire and increase the heat slowly so that you can have a better-finished product.

It will take some time to get proficient and master the temperature to obtain the heat levels you desire but that is part of the enjoyment of this type of build.

Oil Drum Method

Oil Drum Method

Another low-cost system for your first kiln is the oil drum method.

Materials you will need:

  • An old oil drum with a lid
  • Ceramic fiber blanket (such as Kaowool)
  • Refractory Cement
  • A burner from a hardware store (the sort used for soldering).
  • A kiln shelf that will fit inside.
  • A propane gas bottle

Note: The shelf, cement and fiber blanket can be purchased from a pottery supplies store.

Here is the four-step process:

  • If you are using an old oil drum then you need to cut a hole in the lid in the top large enough to fit the end of the burner into.
  • Then cut and glue the fiber blanket to the inside of the container. Don’t forget to line the bottom and the lid.
  • Install the shelf.
  • Place the burner into the drum lid and hook up the propane.

Again, it will take some time to get skilled at controlling the temperature to obtain the heat levels you desire but as with the brick kiln that is part of the fun of this type of construct.

Conclusion

If you make pottery at home or simply want to advance your skills as a potter, you need a pottery kiln in which to fire it.

Sure, you can go to the local pottery store and use theirs but it’s much more convenient and rewarding to have your own.

As you can see, it is quite easy to make one of these DIY kilns.

With the right materials and tools as recommended above, your new homemade kiln will be ready to use in no time.

It’s not difficult to make and doesn’t need any great skill to construct.

It is better to build your own kiln than to buy it because you can determine the shape and size to fit your exact needs and the reward of your new creations can be outstanding.

Have you tried either method?

Let us know in the comments if you have built a DIY kiln or plan to.

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