How to Seal Raku Pottery: A Step-by-Step Guide

  • By: homeshacks
  • Date: March 27, 2023
  • Time to read: 8 min.
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If you are a pottery enthusiast, you may have heard of Raku pottery. Raku is a traditional Japanese pottery technique that involves firing the clay at a low temperature and then quickly cooling it down to create unique and unpredictable patterns on the surface of the pottery.

While Raku pottery is known for its beautiful and distinctive appearance, it is also known for being fragile and porous. To protect your Raku pottery and ensure its longevity, it is important to seal it properly. In this article, we will discuss the steps you need to take to seal your Raku pottery and keep it looking beautiful for years to come.

Raku Pottery Origin?

Raku pottery is a type of Japanese pottery that was first developed in the 16th century by the Zen Buddhist monk, Chōjirō. The word ‘raku’ means ‘enjoyment’ or ‘ease’ in Japanese, and it was originally created for the tea ceremony, which was an important part of Japanese culture at that time.

Chōjirō was asked by the tea master, Sen no Rikyū, to create a new type of pottery that was suitable for the tea ceremony. Raku pottery was born out of this request, and it quickly became popular among tea masters and their followers.

The process of creating Raku pottery involves removing the pottery from the kiln while it is still hot and placing it into a container filled with combustible materials, such as sawdust or leaves. The pottery is then covered to create a reduction atmosphere that affects the glaze and clay body. This creates a unique crackled appearance that is characteristic of Raku pottery.

Today, Raku pottery is still highly valued and sought after by collectors and enthusiasts around the world. It has also inspired many artists to create their own unique styles and interpretations of this ancient art form.

Preparing the Pottery

Cleaning the Pottery

Before you start sealing your Raku pottery, it’s important to make sure that it is clean and free of any dirt or debris. To clean the pottery, you can use a soft-bristled brush and warm soapy water. Be sure to rinse the pottery thoroughly with clean water and let it dry completely before moving on to the next step.

Drying the Pottery

Once the pottery is clean, you’ll need to make sure that it is completely dry before applying the sealant. You can air dry the pottery or use a soft cloth to dry it off. It’s important to make sure that the pottery is completely dry to prevent any moisture from getting trapped under the sealant, which can cause the pottery to crack or break.

It’s important to note that if your Raku pottery has any cracks or chips, you should repair them before sealing the pottery. This will help to ensure that the sealant adheres properly and that the pottery is protected from further damage.

Applying the Sealant

Choosing the Right Sealant

Choosing the right sealant is essential to ensure that your Raku pottery is properly protected. There are many types of sealants available, but not all of them are suitable for Raku pottery. Some of the most commonly used sealants for Raku pottery include:

  • Clear acrylic spray
  • Wax-based sealant
  • Oil-based sealant

Each of these sealants has its own advantages and disadvantages, so it is important to choose the one that best suits your needs. Clear acrylic spray is a popular choice because it is easy to apply and dries quickly. Wax-based sealants provide a more natural look but require more maintenance. Oil-based sealants are more durable but can be difficult to apply.

Applying the Sealant

Before you start applying the sealant, make sure that your Raku pottery is completely dry. You should also clean it thoroughly to remove any dirt or debris. Once your pottery is clean and dry, you can begin applying the sealant.

If you are using clear acrylic spray, simply hold the can about 6 inches away from the pottery and spray a light, even coat. Be sure to apply the sealant in a well-ventilated area and wear a mask to avoid inhaling any fumes.

If you are using a wax-based or oil-based sealant, you will need to apply it with a brush. Dip the brush into the sealant and apply a thin, even coat to the pottery. Be sure to cover all surfaces, including the bottom of the piece. Allow the sealant to dry completely before applying a second coat.

Once you have applied the sealant, allow it to dry completely before handling your Raku pottery. This will ensure that the sealant has had enough time to cure and will provide the best possible protection for your pottery.

Firing the Pottery

Preparing the Kiln

Before firing the pottery, you need to prepare the kiln. Make sure the kiln is clean and free of any debris. Place a layer of sand or a kiln shelf on the bottom of the kiln to prevent the pottery from sticking to the kiln floor. Arrange the pottery pieces in the kiln, leaving enough space between them for the flames and heat to circulate.

It’s important to note that raku pottery is fired at a much lower temperature than other types of pottery, typically around 1800°F. This means that you can use a small kiln or even a portable propane-fired kiln for firing raku pottery.

Firing the Pottery

Once the kiln is prepared, it’s time to fire the pottery. The firing process typically takes between 30 minutes to an hour, depending on the size of the kiln and the number of pottery pieces being fired.

During the firing process, the pottery will undergo a rapid temperature change, which is what gives raku pottery its characteristic crackled glaze. The pottery is heated until it reaches a bright red color, then removed from the kiln with tongs and placed into a container filled with combustible materials, such as sawdust or newspaper.

The combustible materials ignite on contact with the hot pottery, creating a reduction atmosphere that causes the glaze to crackle and change colors. The pottery is left to cool in the container for several minutes before being removed and rinsed with water to remove any remaining ash or debris.

It’s important to wear protective clothing, such as gloves and safety glasses, during the firing process, as the kiln and pottery can reach extremely high temperatures.

Tip:Experiment with different types of combustible materials, such as leaves or pine needles, to achieve different effects on the glaze.

By following these steps, you can successfully fire your raku pottery and achieve the unique crackled glaze that makes this type of pottery so popular.

Cooling and Finishing

Cooling the Pottery

After the pottery has been removed from the kiln, it will be extremely hot. It’s important to let it cool down gradually to prevent cracking or other damage. One way to do this is to place the pottery in a container filled with combustible materials, such as sawdust or newspaper. This will cause the material to smolder and create smoke, which will then be absorbed by the pottery. The smoke will create unique patterns and colors on the surface of the pottery.

Another method is to place the hot pottery in a container filled with water or sand. This will cause the pottery to cool down more quickly, but it may also cause cracking or other damage. It’s important to monitor the pottery closely and remove it from the container as soon as it has cooled down enough.

Removing the Residue

Once the pottery has cooled down completely, it will be covered in a layer of residue. This residue is a result of the combustion process and can be removed using a wire brush or sandpaper. Be sure to wear gloves and a mask to protect yourself from the dust and debris.

After removing the residue, you can add a protective coating to the pottery to help preserve it. One option is to apply a layer of wax or oil to the surface of the pottery. This will help protect it from moisture and other environmental factors. Another option is to apply a clear glaze to the pottery. This will give it a glossy finish and make it more durable.

How to Shine Raku Pottery?

After the firing process, your Raku pottery will have a unique, matte finish. If you want to add some shine to your piece, you can use a few different techniques.

One option is to use a clear glaze. You can apply this glaze to the surface of your piece and then fire it again. This will give your pottery a glossy finish. However, keep in mind that this will also alter the appearance of your piece, so it’s important to consider whether or not you want to make this change.

Another option is to use a wax or oil-based polish. This will add shine to your piece without changing its appearance. You can find these types of polishes at most craft stores. Apply the polish with a soft cloth and buff the surface until it shines.

It’s important to note that Raku pottery is not food-safe, so if you plan on using your piece for anything other than decorative purposes, it’s important to keep this in mind. Additionally, be sure to handle your Raku pottery with care, as it is more delicate than other types of pottery.

Raku Firing Temperature?

The Raku firing process is a unique way of firing pottery that originated in Japan. It involves removing the pottery from the kiln while it is still hot and placing it in a container filled with combustible materials, such as sawdust or newspaper. The heat from the pottery ignites the combustibles, creating a reduction atmosphere that gives the pottery its unique finish.

The Raku firing temperature is typically around 1800°F (982°C), although it can vary depending on the type of clay and glaze being used. The firing process is relatively quick, usually taking only a few hours from start to finish.

It is important to note that Raku firing is not suitable for all types of pottery. The process can be quite unpredictable, and there is always a risk of cracking or other damage to the pottery. Additionally, the finished pieces are not food safe and should not be used for functional purposes.

Despite these limitations, Raku firing remains a popular technique among potters due to the unique and beautiful finishes that can be achieved. If you are interested in trying your hand at Raku firing, be sure to do your research and work with an experienced potter to ensure that you are using the proper techniques and safety precautions.

Raku Reduction: What is it?

One of the most distinctive features of Raku pottery is the use of a reduction process. This process involves removing the pottery from the kiln while it is still glowing hot, and then placing it in a container filled with combustible materials, such as sawdust, paper, or leaves. The container is then sealed, and the pottery is left to cool down slowly.

During this cooling process, the combustible materials ignite and create a reduction atmosphere inside the container. This atmosphere is characterized by a lack of oxygen, which causes the glazes on the pottery to undergo a series of chemical reactions.

The reduction process can have a significant impact on the final appearance of the pottery. It can create a range of unique colors and patterns, including metallic lusters, crackles, and crazes. It can also affect the texture and feel of the pottery, making it rougher or smoother depending on the specific technique used.