Raku firing is a fascinating and ancient pottery technique that originated in Japan centuries ago. It has since evolved into both Eastern and Western styles, each with its unique characteristics and aesthetic appeal.
In this guide, we will explore what Raku firing is, the difference between Western and Eastern methods, and look at how the Raku firing process works. Are you ready? Let's get started!
What is Raku Firing
Raku firing is a traditional Japanese pottery technique known for its unpredictability and unique results. It is often characterized by its crackled glaze and vibrant colors, making it a sought-after art form for many collectors and enthusiasts.
The process involves removing the pieces from the kiln while they are still glowing hot and placing them in a chamber with combustible materials like sawdust or charcoal, or other organic matter, so that when the matter burns, it creates an oxygen-deprived environment. This rapid cooling process and lack of oxygen results in the crackled glaze and unique color patterns that are typical of Raku pottery. Raku firing without the glaze means the oxygen is extracted from the clay. This leaves a matte-black finish in some areas. Because Raku firing is unpredictable, you’re guaranteed to get a unique design every time you go through this process.
It is also much faster than normal firing. Normal firing techniques can take up to 24 hours for the full design whereas Raku firing is only 1-2 hours. If you’re a potter, Raku firing is a great way to test new styles and techniques. There’s always an exciting anticipation of how the piece will turn out.
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Western-Style Raku Firing
In the 1960s, an American ceramicist named Paul Soldner revolutionized the ancient Western styles of Raku through innovative techniques. He introduced the concept of 'low-temperature salt firing,' encouraging his students to embrace the unexpected and explore the possibilities it brings. Soldner's approach highlighted the beauty and thrill arising from chance effects resulting from the interaction of combustible materials and hot glaze during the smoking process. Embracing mistakes as opportunities, he believed they could lead to creative breakthroughs. Today, his renowned ceramics are celebrated worldwide.
Unlike traditional firing methods, Western-style Raku firing involves rapid low-temperature heating, which adds an element of unpredictability to the final outcome. Potters are drawn to this approach because of the excitement it brings. Western Raku pieces are typically crafted from stoneware and subjected to temperatures around 1,650 F.
Paul Soldner's legacy lives on as his innovative techniques and philosophy continue to inspire ceramic artists worldwide, encouraging them to explore the enchanting realm of Raku pottery.
Eastern-Style Raku Firing
In Eastern and Western Raku firing, the initial steps are similar: loading the Raku ceramics into a cold kiln and rapidly heating it. However, the firing cycles can vary significantly. While Eastern Raku firing involves short cycles, sometimes as brief as 15 to 20 minutes (in contrast to the traditional 10-hour cycles), Western Raku firing introduces a post-firing reduction process. The difference lies in the next stage of the process: Eastern Raku undergoes rapid cooling in open air or is immersed in water for cooling.
Interestingly, in Eastern Europe, there's an intriguing variation of the firing technique known as Obvara. To prepare for this method, a mixture of yeast, flour, and water is concocted three days before the firing. After the ceramic work has been biscuit fired, it's removed from the kiln and dipped into the yeast mixture before being plunged into water. As the piece steams, it develops a fascinating and burnished surface, resulting in a unique finished appearance. The Obvara technique adds an extra dimension of artistry to Raku ceramics in this region.
How Does Raku Firing Start?
Raku firing starts with the creation of the pottery pieces. The clay is shaped and left to dry to a specific moisture level. Then, the pieces are bisque-fired in a kiln to remove any remaining moisture and strengthen the clay body. Once bisque-fired, the pieces are ready for glazing.
The first step is to apply a specialist Raku glaze to your ceramic ware. It’s worth mentioning that any type of glaze can be used for Raku, whether it’s dipped, splashed on, or sprayed. However, because Raku firing is a low-fire process, you’ll need to make sure the glaze can melt at these lower temperatures (around cone 06 to cone 010) For the Raku technique to yield its desired effect, it is recommended to apply a thin layer of glaze, which also facilitates a faster melting point. You can find these specialized Raku glazes at select craft shops and pottery equipment wholesalers.
We recommend you become acclimated to kiln temperature ranges, so your clay and glaze can develop correctly.
The Raku Firing Process
Before starting the Raku firing process, you need to load your wares into the kiln and gradually raise the temperature to 1850 degrees Fahrenheit, which typically takes about an hour. While the firing is ongoing, it's essential to monitor the ware every 15 minutes after 45 minutes have passed. Once you notice the glaze starting to bubble, it indicates that the process is working correctly. Allow the ware to continue firing for an additional 15 minutes before proceeding to the next stage.
The critical moment to remove your ware from the kiln is when it glows red and the glaze surface appears shiny and liquid. While you're waiting for the kiln process, you must prepare a vessel for reducing the oxygen around the piece. A metal dustbin or similar container can be used, and you can add shredded newspaper or sawdust. Ensure that the vessel is only slightly larger than the ware you plan to place inside. A snug fit will promote better oxygen reduction, leading to a more vibrant color spectrum in the final piece.
Once the ware inside the kiln achieves a red hot glow, you'll need three people to carry out the Raku process. One person should open the kiln door, another uses tongs to carefully remove the pieces from the kiln and place them in the prepared metal container, while the third person quickly seals the lid on the vessel. This stage requires wearing appropriate protective gear, as the ware will be extremely hot.
When removing the ware from the kiln, close the door between each piece to retain the required heat. Place the pieces into the waiting vessels as swiftly as possible to preserve the heat. Because the clay piece will be at a temperature of over 1650F, the organic material will ignite when placed in the bin.
Next, wait a few minutes for the smoking effect to take hold. Caution is necessary when removing the lid, as the smoke can be hot and may cause facial burns if not handled carefully. Additionally, remember that the wares remain extremely hot at this point, so handle them with care. Always make sure you are wearing heat proof gloves and gauntlets and eye protection like safety glasses and long sleeve cotton shirts, pants, and closed toed shoes to protect your skin from flying embers. To cool the ware, pour some water onto them and then use tongs to submerge the pieces in a bucket of water. Now, you should be able to see the unique effects the Raku firing technique has imparted on your finished ware.
Best Kilns for Raku Pottery
There are a variety of low-fire Raku kilns ideal for potters interested in Raku firing techniques. Raku kilns exist in a variety of sizes, allowing artists to select the one that best suits their needs. Smaller Raku kilns are good for beginners, while larger kilns cater to intermediate potters who want to experiment with different Raku firing procedures and create larger Raku works. These are some of the best options available on the market:
Mid-Range Kiln Options for Raku Pottery
For beginners and intermediate potters experimenting with Raku firing procedures, portable and smaller Raku kilns are recommended. Raku firing is frequently done outside, and smaller kilns are easier to manage and transport. Here’s a great example of an easy and portable kiln that can be used for Raku and will hit mid-range firing temperatures:
Thanks to the unique designs and serendipitous patterns Raku firing is a captivating pottery technique that has captured the hearts of artists and collectors around the world. The blend of ancient tradition and contemporary creativity gives Raku pottery its timeless appeal. Whether it's the Western style with its modern adaptations or the Eastern style honoring the classic methods, Raku firing continues to be a cherished art form that mesmerizes all who encounter it.