How to Make Raku Pottery

Raku pottery is a traditional Japanese firing technique that emphasizes spontaneity and experimentation. Unlike conventional methods, Raku involves removing pottery from the kiln while it is still red-hot and immediately placing it in containers filled with combustible materials. This process creates unique, unpredictable color effects and textures on the surface of each piece, making every creation genuinely one of a kind.

There are numerous benefits to making raku pottery. Artists and hobbyists alike are drawn to the expressive nature of this technique, which allows for vibrant finishes and fascinating results. Each piece tells its own story, shaped by fire, smoke, and chance.

This article serves as a comprehensive guide on how to make Raku pottery, taking you through the entire process step by step. From preparing your clay and glazing your piece to expertly managing the firing and post-firing stages, you’ll learn how to master this ancient yet rewarding craft.

Materials and Tools Needed

Creating Raku pottery requires specific materials and tools to complete each stage of the process successfully. Below is a list of the essential items you’ll need to get started:

Essential Materials

• Clay: Use Raku clay or any clay that can withstand high-temperature firing. This type of clay is specially formulated to endure the rapid cooling and thermal shock of the Raku process. 
• Glazes: Opt for Raku-specific glazes or other high-temperature glazes designed to produce vivid colors and unique textures during the firing and reduction process. 
• Combustible Materials: Items such as sawdust, newspaper, or straw are critical for the post-firing reduction phase, creating smoke and texture on the pottery surface. 
• Pottery Tools: You’ll need shaping tools like sponges, rib tools, and carving tools to work the clay and create your designs. 
• Protective Gear: To ensure safety while working, wear heat-resistant gloves and safety glasses and use sturdy tongs to handle your pottery during and after firing. 

Tools for Firing

• Raku Kiln or High-Temperature Kiln: A specialized Raku kiln is often preferred due to its ability to handle quick temperature changes, but any high-temperature kiln can work for this method. 
• Tongs or Pliers: These tools are crucial for removing hot pottery from the kiln safely and effectively. 
• Containers for Post-Firing Reduction: Metal cans or trash bins with lids work well for the reduction phase as they can trap smoke and control airflow during cooling. 

Having all the appropriate materials and tools ensures a smoother and safer Raku pottery experience, allowing you to focus on your creativity and expression. 

Preparing the Clay

Step 1: Choosing the Right Clay 

Raku clay is specifically formulated to endure the rapid temperature changes involved in the Raku firing process. Unlike traditional clay, it contains grog or sand, providing exceptional thermal shock resistance and reducing the risk of cracking or breaking during firing. This clay’s durability makes it ideal for the quick and dramatic cooling required in Raku pottery. Selecting high-quality Raku clay ensures better performance, allowing your artwork to survive the intense conditions of the process.

Step 2: Shaping Your Pottery 

When crafting pieces for Raku firing, the shaping stage is crucial. Techniques like wheel-throwing and hand-building are commonly used and adapted to create designs that suit Raku’s unique aesthetics. Starting with small to medium-sized pieces is recommended, as these dimensions are more likely to withstand the rapid cooling process while maintaining structural integrity. Focus on simple forms and avoid overly delicate features to minimize potential damage during firing. This approach ensures a balance between creativity and practicality.

Step 3: Drying the Piece 

Proper drying is essential in preparing pottery for Raku firing. Allow your piece to dry gradually to prevent cracking caused by uneven moisture levels. Ensure the piece reaches a leather-hard consistency, where it is firm but still workable, before proceeding to the bisque firing stage. Testing for dryness by touch or observing the clay’s uniform color can help confirm readiness, setting the stage for the next steps in the Raku pottery process.

How to Make Raku Pottery: Bisque Firing the Pottery 

Bisque firing is a crucial step in the Raku pottery process that transforms the fragile dried clay into a hardened ceramic form, ready to accept glaze.

Step 1: Preparing for Bisque Firing 

Place the pottery carefully in the kiln, ensuring that pieces do not touch each other to allow even heat distribution. Gradually heat the kiln to around 1,800°F (982°C) to thoroughly dry and harden the clay. This slow heating process is essential to avoid cracks or breakage caused by thermal shock. Bisque firing creates a durable yet porous surface, strengthening the pottery for subsequent glazing and Raku firing stages.

Step 2: Firing Process 

Begin the firing by slowly ramping up the kiln temperature in stages, allowing any residual moisture to escape from the clay gradually. This controlled increase in temperature minimizes the risk of rapid steam expansion, which can cause cracking. Maintain a consistent final temperature to ensure the pottery is uniformly fired. During the bisque firing process, organic materials in the clay burn off, leaving behind a stable and porous ceramic structure capable of absorbing glaze. This step is critical for preparing the piece for the dynamic thermal changes in Raku firing.

Step 3: Cooling and Preparing for Glazing 

Once the kiln reaches the peak bisque firing temperature and holds it for the necessary time, begin cooling the kiln slowly to prevent thermal shock. After the pottery has cooled completely, carefully remove it from the kiln. Clean the surface of each piece with a damp sponge or soft cloth to remove any dust or debris that may interfere with the glazing process. With the bisque-firing complete, the pottery is now ready for glazing, the next step in the Raku process.

Glazing the Pottery 

Step 1: Choosing the Right Raku Glaze 

Raku glazes are integral to the unique aesthetic of Raku pottery, adding striking finishes to each piece. These glazes typically result in vibrant, textured, and unpredictable outcomes. Crackle glazes are popular, creating a web-like effect as the surface glaze cools and contracts after firing. On the other hand, copper-based glazes produce stunning metallic or iridescent finishes, often displaying shades of reds, greens, and blues based on the reduction environment. Celadon glazes offer a translucent, glass-like effect, showcasing intricate details of the pottery’s surface while adding a subtle layer of color. The choice of glaze depends on the desired visual and artistic outcome, and experimenting with combinations often results in unique, captivating patterns. 

Step 2: Applying the Glaze 

Once the glaze is selected, apply it to the bisque-fired pottery. There are several methods to choose from, including dipping the pottery into the glaze for even coverage, brushing the glaze on for more precise application, or spraying it on for a thin, controlled layer. Whichever technique is used, ensure the glaze coats the surface evenly, avoiding drips or pooling. Allow the glaze to dry completely before moving to the firing stage, as any moisture can affect the firing process and final finish. 

Step 3: Firing the Pottery Again 

After the glaze has dried, the pottery is ready for its second firing in the Raku kiln. Heat the kiln to approximately 1,800°F (982°C), allowing the glaze to react with the heat. This firing process typically takes 20-30 minutes. Carefully observe the pottery during this stage, noting changes in glaze color and texture, which signal when the pottery is ready to be removed from the kiln. At this point, the distinct and unpredictable beauty of Raku pottery truly begins to emerge. 

Post-Firing Reduction Process

Step 1: Removing the Pottery from the Kiln 

Using tongs or pliers, carefully remove the hot pottery from the kiln while it is still glowing. Handling the pottery with caution is crucial due to its extreme temperature. Once removed, place the pottery immediately into a metal container filled with combustible materials such as sawdust, newspaper, or straw. These materials will ignite upon contact with the intense heat of the pottery, starting the reduction process.

Step 2: Creating the Reduction Atmosphere 

Quickly and securely close the metal container to trap the smoke and limit oxygen flow. This action creates a reduced atmosphere, an environment with less oxygen. The interaction between the smoke, reduced oxygen, and the heated glaze on the pottery surface is what gives Raku pottery its characteristic visual effects. Unique color patterns, metallic finishes, and crackle textures often emerge during this stage, making each piece of Raku pottery one of a kind.

Step 3: Timing the Reduction 

Allow the reduction process to continue for approximately 10-20 minutes. During this time, the intense heat and smoke interact with the glaze, and the pottery transforms. Observe safety precautions while monitoring the time if needed. The duration of this stage can significantly influence the final appearance of the pottery, with longer reduction times often enhancing crackling effects and darkening exposed clay areas. After this period, the pottery will be ready for the final cooling stage.

Cooling and Unveiling the Pottery

Step 1: Quenching the Pottery 

After the reduction process, carefully remove the pottery from the container while it is still hot. Use protective gear, such as heat-resistant gloves and tongs, to handle the pieces safely. Some artists choose to place their pottery directly in water to cool it quickly. This method, known as quenching, can enhance the color patterns and crackling effects, contributing to the distinctive character of the finished piece. However, it is important to be cautious during this step, as the rapid temperature change might cause fragile pieces to crack.

Step 2: Unveiling the Raku Finish 

Once the pottery has completely cooled, the final step involves cleaning off any soot or residue on its surface. You can use a soft cloth or mild abrasive to gently polish the surface, revealing the unique finish created during the reduction process. Each piece will display one-of-a-kind color patterns, textures, and crackling, reflecting the interplay of fire, smoke, and glaze. These unpredictable and artistic variations are hallmarks of the Raku pottery technique, showcasing the beauty of imperfection and the organic nature of the craft.

Troubleshooting Common Issues

Cracking or Breaking During Firing

Cracking or breakage during firing is often caused by uneven drying or firing the pottery too quickly. Rapid heating can lead to steam buildup and stress when moisture remains in the clay body, resulting in cracks. To prevent this, ensure that your pieces are evenly dried before firing by allowing them to air dry thoroughly in a well-ventilated area. Covering them lightly with plastic during the initial drying stage can also help control the drying rate. Gradual heating during the firing cycle, especially in the early stages, is essential to avoid thermal shock.

Uneven Glaze Results

Uneven glaze results can be attributed to improper glaze consistency, overly thick application, or uneven coating. To address this, always mix glazes thoroughly before use to ensure consistency. Test the glaze on a small piece to verify the thickness and adjust with water if necessary. When applying glaze, use smooth, even strokes, and rotate the piece to ensure every surface is coated uniformly. Avoid applying multiple heavy layers, as this can cause drips or bare patches during firing.

Poor Color or Texture Results

Achieving the desired color and texture involves fine-tuning the reduction process. Variations in the amount and type of combustible material and the timing of the reduction can greatly influence the outcome. Experiment with different organic materials like newspaper, sawdust, or leaves to explore new effects. Additionally, consider the reduction duration—shorter or longer times can yield varying results. Testing on small sample pieces will help refine your techniques to attain the colors and textures you envision.

Conclusion

Raku pottery is a fascinating and creative process that allows for endless artistic possibilities. Every step contributes to the final masterpiece, from preparing the clay and bisque firing to glazing and the dramatic reduction phase. Understanding how to make raku pottery involves experimentation and an openness to unexpected outcomes, as no two pieces will ever be identical. This unpredictability is part of its charm, making it a truly rewarding craft. Practice patience, refine your techniques, and enjoy the surprises that emerge from this ancient art form, where each piece tells its own unique story.