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Hello and welcome to Clay Corner, Syria's online classes on hand-building ceramics. Today, we'll be sharing with you some basic information about the different stages of clay and what kind of tools you should have in your studio. If you're just starting, here are some essential tips and tricks on how to store, wedge, and clean up clay in your workspace.
Natural clay comes in three main ranges: earthenware, which is low-fired; stoneware, which is mid-fired; and porcelain, which is high-fired. Each of these types of clays go through different stages as they dry.
When the clay is soft and malleable, it is called plastic clay because you can easily bend it and work with it without breaking and cracking. Plastic clay is ideal for coiling, pinching, and wedging, and can take on texture very well. Keep in mind that soft clay is not wet clay.
As it dries a little, the clay enters the leather stage, when it is no longer sticky to the touch and can hold its shape when standing upright. At this stage, you can still get away with shaping it and bending it a little without cracking. Leather clay is ideal for slab building and for scoring and slipping, or in other words, attaching two pieces together.
The next stage is leather hard, and it is when the clay can no longer be bent, but it is not yet completely dry. This stage is great for cleaning up and polishing the piece, such as smoothing it down with a wet sponge or trimming and carving.
When the clay is completely dry, it is called bone dry. At this stage, you can no longer bend, attach, or shape it. However, you can still buff and sand it. The piece is quite fragile at this stage and not functional until fired.
One use for bone dry clay is making slip. Slip is a liquid or paste form of the clay, which is made using bone dry clay and water. Since bone dry clay absorbs water much faster than any other stage of clay, slip can be used like glue to attach pieces of clay together, or sometimes we use it to slip cast into plaster molds.
Pieces made with clay in all its stages before firing are called greenware and are not yet ceramic pieces. The first firing that clay goes through to become ceramic is called a bisque firing. Ceramics are fired in a kiln, which is an oven made for ceramics that fires to very high temperatures of over a thousand degrees Celsius. Firing can happen at different ranges for different types of clays and glazes.
Once bisque fired, the unglazed ceramic piece is called a bisque and it is not yet functional or food safe until it is glazed and fired again. After a glaze firing, you now have a completed ceramic ware.
When clay is left exposed to air, it will naturally dry out. So, to keep your clay moist and soft, it must be stored in a damp, airtight container, such as a Ziploc bag. If your clay has hardened a little, you can also wrap a damp cloth around it to rehydrate it before sealing it in the bag.
Another option is to store clay in a damp box, which has been filled a quarter of the way with plaster that has been saturated with water, which creates a humid environment that is ideal for keeping the clay soft for weeks or even months.
To rehydrate bone dry clay, you can either place it in a wet kitchen towel and in a Ziploc bag and allow it to slowly soak in the moisture over the next several days, or you can reclaim it by turning it into slip first. You'll often see a clay reclaiming bin in ceramic studios where you can throw in your bone dry clay to recycle. When the clay has turned to slip, it's then spread on a plaster surface to dry out until it reaches the plastic stage.
Before using any clay to create your masterpieces, you must wedge the clay first to release any air pockets that might be trapped inside it. This is very important because trapped air can shatter the piece in the kiln or create stresses or weak points in your ceramic pieces. There are different ways to wedge your clay, and the method shown here is called a ram's head. You need to make sure that you do not fold in your clay because that can create new air pockets. The goal here is to knead the clay very gradually to turn it inside out until all the air inside it is released, and you must be careful not to strain your wrists while wedging.
When working with clay, it's important to use a non-stick surface. Clay will stick to non-porous or polished surfaces like plastic, glass, or metal. So, instead, you can work on an unpolished wood, or even if you don't own one, then you can cover your table with unprimed canvas or use pieces of plywood to work on.
When it comes to using clay tools, there is always more than one function that you can use each for. Just go with your instincts and see what fits the purpose you need. Here are some examples of basic tools that you can have: a rolling pin and rolling guides to create slabs. Rolling guides can come in different thicknesses and help you maintain an even thickness throughout your piece. A wooden paddle is handy in manipulating the shape of a clay object by patting it down. Potter's knives to cut the clay. Different ribbon tools to carve your piece. Scoring tools to score your clay before applying slip and attaching pieces together. Pin tools and shaping tools for details. Your basic wooden clay tool, which is very versatile and can be used to smoothen edges, reach into hard-to-reach spots, shape, or engrave into your clay. Brushes to apply slip or water or smooth any joints. Ribs are used to smooth the texture and compress clay slabs and can come in wood, steel, or rubber. Having a slip jar made from the same clay body that you use in your studio is a must if you're joining pieces of clay together. It's a good idea to have rags and hand towels about in your studio for cleanup and other purposes. A wet sponge helps you smooth your clay. You'll often need a small bucket of water and a water spray bottle at hand to clean up and rehydrate your clay. To clean up your surface, a scraping tool and hand brush are good to have in your studio. Banding wheels help you rotate and work your piece from all angles without the hassle of moving around it yourself. Since it's made of metal, it's a good idea to place a piece of plywood board between it and the clay. Plaster molds are easy to make by casting them in everyday household objects like buckets, bowls, and cups, and are very handy when it comes to hand building.
There are hundreds of objects that you can use for applying texture onto your clay, and some examples are texture rollers, doilies, and serrated ribs.
It's important to understand how to dispose of clay water properly because simply pouring it down the drain can severely clog your pipes. The best thing to do is allowing the clay to settle at the bottom of the bucket overnight, which would separate it from the water. Very carefully pour out the clean water, then throw out the settled clay at the bottom of the bucket. Similarly, if you don't have a clay sink trap, you'll want to wash your hands and tools over a bucket, and the sink, which will catch any clay that falls into it and allow the excess water to overflow. To clean up your working surface, use your scraping tool to remove any dry chunks of clay, and you can then easily brush them away and wipe your surface with water.
We hope that you found this video useful and informative. If you're a beginner just starting out, please make sure to check out our online classes to learn more about how to work with clay to create functional ceramics and fun projects, whether you're a beginner or an experienced potter.