Fire It Up Series: Methods and Techniques for Firing Pottery

Firing your clay piece is often the most nerve-racking yet exciting step in finishing your project! There is always something that could go wrong, such as a piece with an air bubble that ruins all of your work being fired with it. Are we making you anxious yet? Even though things can go wrong when firing ceramics, a lot can go right!

At DiamondCore® Tools, we get pretty fired up about firing — so much so that we’re inspired to launch a new blog series! Stay tuned: The Fire It Up series from DiamondCore® Tools will describe various methods for firing pottery and explain techniques that can help you achieve different textures and colors on your ceramic projects. 

Oxidation Versus Reduction

Oxidation firing is when there is an ample supply of oxygen in the kiln while firing. During this process, the oxygen molecules attach to the pottery and interact with the glaze and the clay surface. While the piece is firing, the oxygen has high electronegativity, which attracts electrons from the glaze and clay, causing them to oxidize.

Reduction firing happens in the opposite environment when the amount of oxygen in the kiln is restricted. Because of this, other gases — such as carbon, hydrogen and carbon dioxide — build up in the kiln. This changes the oxides in the kiln and the clay, altering the color and texture of your pottery pieces.

Kiln Styles for Firing Clay

As mentioned above, different methods for firing clay will create various textures and/or colors on your pottery pieces. Now let’s examine some of the common and unique ways to fire your pottery to create amazing finished ceramic projects.

1. Electric Kilns

Electric kilns are the most common way to fire your pottery. They are typically less expensive, and their built-in digital controls make them easy to use. Electric kilns are lined with insulating bricks and, depending on what style they are, can either be loaded from the top or from the front.

To fire your work, the coils surrounding the pottery heat up. This ensures that the pieces inside are heated evenly. Electric kilns are reliable and are pretty simple to use, especially since you can set the kiln to fire your pieces on a schedule.

2. Gas Kilns

Gas kilns are not as common as electric kilns but are still used today. They can be used for salt or soda firing, which can create different textures and colors compared with pieces fired in an electric kiln. The flames inside the kiln can be adjusted to change the atmosphere in the kiln, in turn, adjusting the color and textures of your pieces.

3. Wood-Burning Kilns

Wood-burning kilns aren’t as common these days, but they’ve been used for centuries to fire pottery. Potters usually build them out of bricks or adobe, shaping them like small caves or igloos. While it might seem like a straightforward, DIY method, it’s actually a lot of work and can take a team several days just to complete one firing.

Even though this method takes so long, it is the most organic of these firing methods and the finished ceramics often have a beautiful, rustic look.

Methods for Firing Clay

Now that you know the different kiln styles for firing your clay, we’ll examine some different firing methods you can use to finish your pieces. Firing your clay using these techniques can give your pieces unique, personal looks.

1. Soda Firing

In soda firing, baking soda and sodium carbonate are added to the kiln when it hits about 2,350°F. The heat turns them into vapor, which swirls around and sticks to the pottery, forming a textured glaze. Since the vapors move unpredictably, you never know exactly how each piece will turn out—making every firing a surprise!

2. Raku Firing

Raku firing is a bit tricky, so be cautious! You remove the pottery from the kiln while it's still glowing hot and place it in a container with sawdust or paper, which catches fire. This creates a low-oxygen environment that results in some unique, unpredictable effects. The way you cool the pieces can even give them a crackled look, and no two pieces will ever be the same.

3. Sawdust Firing

Sawdust firing involves a kiln that you make yourself with bricks or stones placed together. You then pack the inside of this “cave” with sawdust, place your pottery on top, then put more sawdust on top of the pieces. This type of firing can take time — up to 36 hours!

The pieces that come out of this firing method are usually smoky black or other dark colors. Once the pottery is finished, a natural glaze or wax can be applied.

Conclusion

We recommend firing your pottery using the methods and techniques you are most comfortable with. Once you get more skilled, you can try different firing methods that will give your ceramic pieces a look that is unique to you. Make sure that you take the time to fully understand each process and how each firing method will affect your pottery in the kiln. This can require a lot of patience, but it will be worth it to see your finished piece coming out of the kiln with all that hard work paying off!

Have questions about safety or selecting the best firing techniques for your projects? We're happy to assist! Feel free to leave a comment, send us an email at info@diamondcoretools.com, or reach out to us on social media. You can find us on Facebook and Instagram!