Raku Pottery - A Beginner’s Guide to Making Raku

Raku Pottery – A Beginner’s Guide to Making Raku

Posted on by Kate Young

To find your niche in pottery, we advise potters to try out as many methods as possible.

However, mainstream pottery techniques can be intimidating, especially with their high-temperature firing.

That is why we recommend raku as a way to edge into pottery!

Since it is a low-temperature method of pottery that’s used to create decorative pieces, you can dip your toes in the water and experiment to your heart’s content without worrying as much.

So, to help you on your pottery journey, we’ve created this beginner’s guide to making raku.

By the end of this article, you will have all of the knowledge you’ll need to start creating your own beautiful raku pieces!

Table of Contents

What Is Raku

Raku is a form of pottery created in Japan during the 16th century and has evolved over the years into a more modern, Western form. 

It is characterized by a low-temperature firing, accompanied by decorative methods that allow for unique designs.

However, raku pottery is porous and easily chipped. Thus, it can’t be used for holding water or food and is mainly used for decorative pieces.

Raku Supplies and Equipment

To make raku pottery, you will need to obtain some basic supplies and equipment. 

Here is a list of the very basic supplies and tools you need:

If you choose to cool your pottery using a reduction chamber, you will also need the following:

  • Metal can with a lid to use as a reduction chamber
  • Scrap paper, sawdust, or other combustible material to fill the reduction chamber

Raku Clays

Technically, any clay can be used for raku, but some do better than others – which is why we’ve identified how certain clays react when used for raku pottery.

Earthenware 

Unfortunately, earthenware is made for low-firing methods, making it less than ideal for raku pottery. 

Because it matures more during the firing and contains more iron, earthenware reacts less to carbon impressions, which gives raku its unique appearance.

So, although you can use earthenware clay for raku pottery, you won’t be able to experiment as much when it comes to appearance.

Porcelain

Porcelain is an excellent clay to use for raku pottery, especially for a refined, lustrous product.

However, if you’re just starting, take note that porcelain is the hardest clay to handle, so we recommend gaining some experience beforehand. 

If you do end up using porcelain clay, make sure to choose one with enough grog and fire it under 1200°F (649°C).

Stoneware

Light-colored stoneware clay is perfect for raku pottery since it’s the easiest to handle. It contrasts nicely with the carbon impressions and matures just enough to create functional pottery.

We recommend grogged stoneware to decrease the chance of cracking. If you’re planning to wheel-throw your pottery, just make sure you choose stoneware with fine grog so your hands won’t hurt.

Special Raku Clays

If you’re reeling from all the different types of clay, don’t worry! 

There are clays made especially for raku, so you don’t have to stress finding clay with the right grog. These clays reduce the likelihood of cracking and are especially helpful for making bigger pieces.

Shaping Raku Pottery

Now that you’ve picked out your clay, you’ll need to shape your pottery! 

Once you’ve wedged your clay, you can use any technique to form your pieces.

If you want smaller, simpler pieces, we recommend hand-building. 

If you want larger, more complex pieces, we recommend wheel-throwing.

However, no matter what technique you use, the general rule is to make sure your pottery has thin, even walls. 

Keeping everything uniform reduces the chance of cracking since all parts will expand and contract at the same rate. Some examples of shapes that do best in raku pottery include orbs, sculptures, and pots.

Remember: the beauty of raku pottery comes from the finish, so focus more on integrity when shaping your piece.

Decorating Raku Pottery

There are many ways to create the look of your raku pottery, and we’ve compiled seven techniques to help you get started: no glaze, crack glazes, copper glazes, wax resist, slip resist, horsehair, and alcohol reduction.

With these basic techniques at your disposal, you’ll be creating unique pieces in no time!

No Glaze

This “naked raku” form requires you to put your raku pottery in a reduction chamber right after the final firing.

When you put your hot pottery in a reduction chamber, any combustible materials inside will burst into flame from the heat. 

You then cover the chamber, cutting off the oxygen supply, which causes the fire to search for oxygen trapped in the pottery clay. 

Since there is no glaze to protect certain areas, the whole piece will turn a matte, black color from accumulated carbon molecules. 

Crackle Glazes

This method also uses a reduction chamber, but a crackle glaze is added to the pottery before the final firing.

So you don’t have to worry about matching cone numbers, we recommend you buy special raku glazes that are made for low-fire pottery.

To use crackle glazes, simply paint them on after the pottery’s bisque firing and before the final raku firing. 

After the raku firing, blow air onto the pottery using a fan or air pump to encourage the glaze to crack.

Finally, transfer the pottery to the reduction chamber, and you should have a cracked pattern on your final product.

Copper Glazes

Like crackle glazes, copper glazes are applied after the bisque firing and before the final raku firing. 

Unlike crackle glazes, copper glazes require the pottery to be put directly into the reduction chamber after firing to undergo more reduction. 

The more reduction copper glazes undergo, the more vibrant the final colors, so make sure your setup allows for speedy transfer!

Wax Resist

Wax resist takes advantage of glazes and reduction to create more complex cracking.

After your pottery is bisque fired, you can paint wax resist on the areas that you want to be exposed to reduction. This will allow you to paint on your glaze without worrying about keeping neat lines.

During the raku firing, the wax will melt off. This will allow the exposed clay to turn black once you transfer the pottery to the reduction chamber.

Although you could use this technique to make a more symmetrical cracked appearance, you can also take advantage of the wax to create more complex patterns!

Slip Resist

Slip resist is another form of “naked raku.” 

After the pottery’s bisque firing, a thick coat of slip is added to the exterior. The pottery is then put in the kiln, usually set to 1450°F (788°C), allowing the slip to dry while in the kiln. 

As it dries inside the kiln, the slip will shrink and expose some parts of the pottery. These exposed areas will turn black in the reduction chamber, and the remaining slip can easily be washed off.

You can also use masking tape to cover areas that you want to leave exposed, creating more complex designs. 

Horse Hair

In this decorating method, the pottery is bisque fired, then raku fired with no glaze. Then, once it’s done firing, it is placed in the open air to cool.

Since it is out in the open, this allows you to place feathers easily, (traditionally horse) hair, or any organic material with natural oils on it. These materials will then burn from the intense heat, leaving sooty traces of carbon.

To bring out the beauty of this technique, we recommend burnishing your pottery before the bisque firing, once it turns leathery.

Alcohol Reduction

Our last decorative method will require a few additional tools, including:

After your pottery is done, take it out from the kiln, set it down in open air, and spray it with isopropyl alcohol. This will reduce the surface.

You then need to transfer it to a metal container with a bed of sand and sprinkle it with some combustible material to create smoke. Finally, cover it with a metal bucket or a Pyrex heat-resistant glass bowl to form your reduction chamber. 

If you want a copper hue, leave the cover on. If you’re going to create a swirl of colors, you can experiment with letting a little oxygen into the reduction chamber.

NOTE: Spraying the hot pottery with alcohol will cause flames, so be sure to wear complete protective equipment. Only do this in an open, well-ventilated area with nothing that might set on fire.

Firing Raku Pottery

Now that we know the different ways to decorate your pottery, let’s talk about what defines raku: the firing process.

Kilns

Kilns play a vital role in developing your raku pottery, with fuel and type greatly affecting your process.

In terms of fuel, you will typically have two choices: gas or electric. 

Gas kilns use propane or natural gas and heat more quickly. However, their temperature is harder to control.

Electric kilns are fully digital, so you have complete control over the settings. However, these take longer to heat up, which makes your raku pottery less durable.

There are also two main types of kilns: top-loading and front-loading. Both types work well, but we recommend front-loading kilns to minimize the risk of bumping into hot parts or dropping your pottery during transfer.

Firing Process

In general, your firing process will follow three basic steps: drying, bisque firing, and raku firing.

Once you form your pottery, you always want to let it go bone dry. This will allow it to shrink before it goes into the kiln, reducing the chance of cracking later.

Then, you want to proceed with the bisque firing, which solidifies your pottery and burns off organic and inorganic materials. If you use stoneware clay, you can start with a temperature of 1650°F (899°C). 

After the bisque firing, you can decorate your pottery before proceeding to the final raku firing, typically using temperatures between 1470°F and 1830°F (799°C and 999°C). However, this can depend on your clay and decorative method.

In general, you want to maintain high enough temperatures to make the pottery durable but low enough to reduce the thermal shock and thus the possibility of cracking.

NOTE: ALWAYS wear complete protective equipment during the firing process. Although raku pottery is a beautiful craft, you still have to take precautions to prevent any injuries.

Extraction Process

After firing your pottery, you’ll have to take it out to cool. But how do you know if it’s ready?

Most potters gauge completion visually if they use a glaze since the glaze will stop bubbling and create a glassy surface once the pottery is done.

However, if you aren’t using a glaze or want a more accurate indicator, you can use a pyrometer, which has a probe that can be used to check the kiln’s temperature. 

You can also use a witness cone, which is placed inside the kiln and will bend over once the proper temperature has been reached.

Cooling Process

Once you know your pottery is ready, you have three main methods for cooling it: open-air, water submersion, or reduction chamber.

For the open-air method, all you need to do is transfer your pottery to a nonflammable surface in a well-ventilated area, then wait until it’s completely cooled.

For the water submersion method, you’ll quench your pottery in a tub full of water, then leave it to cool. This will stop all chemical reactions, making its colors permanent.

You’ll have to prepare a reduction chamber beforehand by filling a metal can with combustible material for the reduction chamber method. When your pottery is done, transfer it into the chamber, cover it with the lid, and leave it there until cooled.

Cleaning Raku Pottery

Now that your raku pottery is done, it’s time to clean it!

Most pottery can be cleaned by water, but there may be times that you’ll need to clean more thoroughly. There are two main ways to do this: using abrasives and using a propane torch.

Using Abrasives

To use abrasives, we recommend testing them out on a small piece of pottery first since some products may be too abrasive for your raku. In general, you can use abrasives on glazed areas but not on unglazed areas.

For glazed surfaces, we recommend pairing a cleaning powder with a scrub of some kind. You could also switch out natural sand for the cleaning powder or mix sand in with the powder. 

If you use a shiny glaze, scrub with vigor to help bring out the color. However, if you use a metallic glaze, be careful not to scrub too much, or you will reduce its luster.

After scrubbing, you may opt to use a metal cleaning pad or a grinder to get rid of any stubborn debris.

Finally, all you have to do is rinse the pottery to remove the dirt and abrasives!

Using a Propane Torch

If you used a reduction chamber, your pottery would probably have some carbon residue on its surface. This happens when the combustion process isn’t completed in the chamber.

So, to get rid of the residue, you can simply complete the combustion process by burning it off with a propane torch!

Gently sweep the flame over your pottery’s surface until all the carbon is burned away, then wash thoroughly.

Conclusion

If you want to create beautiful, unique pieces, raku pottery is the perfect way to edge into pottery! 

With its quick, low-fire technique, you can experiment endlessly and become comfortable with the process of shaping, firing, and cooling pieces.

And although raku is decorative-only, its beauty is perfect for making centerpieces or gifts. All you need to do is limit its contact with water and direct sunlight, and you’ll be able to enjoy it for a long time.

We hope that this guide helped you get started with raku, and we wish you luck on your pottery journey!