Hands in the clay - for beginners

What is clay?
Before we begin, let's learn a little about this subject.

Clay is just earth; but it is not just any earth, it is clayey earth. What does this mean? This means that the particles that make up this type of soil are very, very, very tiny! So when we add water to this clayey soil, the particles bind together so much that we end up with a moldable paste that holds whatever shape we give it.

Another cool thing about clay, or clayey soil, is that when it dries it not only changes color but also hardens and shrinks! Why? Because when the clay dries, the water evaporates and that's why it contracts and becomes hard. Even though it's dry, it's still clay! In fact, if we add water to it, it becomes soft again… That’s how we recycle clay.
But then why doesn’t the clay dishes we have at home break down under water? Because this dish has already been in the oven, at a very high temperature, and the clay has turned into ceramic! In other words, when the clay dries it becomes hard, but only when it is fired above 600ºC. is that it turns into ceramic and its hardening becomes definitive.

Working with clay

We can work with clay anywhere, all you need is a table, a container with water and a cloth to clean your hands. It is not a noisy, polluting or very dirty job; on the contrary, it only does us good.

The best tool for working with clay is our hands. When we need other tools, we can almost always find them in our house, we go to the kitchen and start improvising!

To start the work we only need to know two things:

- The first thing is that the clay sticks to the table if we work directly on it, so we must work on paper, plastic or cloth.

- The second thing is very important so that our work does not get ruined during drying. As we have seen, clay shrinks when it dries. Therefore, we must control the drying so that the piece dries and shrinks evenly. In other words, if we make, for example, a clay basket with a thin handle, and if we leave the entire piece uncovered to dry in the air, what will dry first? The thin strap. Since clay shrinks as it dries, if the handle dries first it will shrink before the rest of the piece, and will likely break. In short: we should cover with plastic the parts of a piece that are most exposed to the air and will tend to dry faster. The goal is to make the entire piece shrink at the same time, and to do this we want to speed up the drying of the thicker parts of a piece and slow down the drying of the thinner areas.

Knowing this, we can let our imagination run wild and model whatever we want!

Leather state is the name given to clay that has already started to dry, that is, it is no longer soft and moldable, but still contains water. At this point the clay has a consistency similar to cheese, and we can cut it without it deforming, but if we bend it it breaks. This is an important phase in drying a piece, as we can then remove it from the mold or turn it upside down without it losing its structure. At the same time, we can cut and glue parts, but not bend. If we stick our fingernail into a piece of clay in a leathery state, it leaves a mark; If it is no longer marked, it is because the clay is no longer in a leathery state, but rather dry.

The leather point is not an exact moment; The clay, when it begins to dry, starts at a soft leathery point and as it dries and hardens it changes to a hard leathery state, until it ends up hardening completely when it dries.

The leather state is the right time to carry out various decoration techniques, from painting with engobes, cutting and gluing, finishing, among many others.

Lambugem/Slip is the name given to the cream we use as glue , to stick different parts of a piece of clay that we are modeling. Lambugem is a creamy liquid that we obtain when we add more water to the clay, that is, it is simply the clay itself, but with more water. We must make our glue from the clay we are working with, that is, this glue must be made with the same clay that we are going to glue, so that the contraction is compatible.

We call this same cream slip when it is in a slightly more liquid state (like thick milk) and it is used to fill plaster molds . You may have some deflocculant added to improve performance.

An engobe is also a liquid clay, which in this case is used to paint the clay when it is in a leathery state. A natural engobe is simply clay diluted in water, the final color of which will be the color of that clay. A natural engobe becomes an elaborate engobe when some pigment (metal oxides or dyes) is added to it that will change the color of that clay. As each clay has different characteristics, namely different contractions, we must always make our engobe from the same clay where we are going to apply it. In other words, if we work with white clay, it is from this clay that we make our engobe.

In short : Lambugem, slip and engobes are liquid clays, with different functions and uses and with slight differences between them.

How to cook clay?

The clay needs to exceed 573ºc. to be cooked; At this temperature a chemical reaction occurs that transforms the clay into ceramic. Although the most common option is to bake the clay in ovens designed for ceramics, it is also possible to build an oven at home (on a patio or balcony because it will produce smoke) or even bake the pieces in a fireplace, campfire or wood stove. When the clay is incandescent it is exceeding the target of 600ºC!

Attention : If we place a piece of clay that is not completely dry in a fireplace, bonfire, etc., it will burst and can cause damage and ruin, so we should not try homemade cooking without being properly informed and prepared.

Painting with engobes

Finished pieces can be painted with engobes . We call engobe a paint made with clay diluted in water. Thus, an engobe is made from the clay itself, to which we can add pigments in order to obtain other colors. Like clay, engobes change color when they dry and, especially, after being fired. In other words, a blue engobe can be raw gray and only after baking the piece does it turn blue.

It is important to apply the engobes to a piece that is still soft or, preferably, in a leather state. This is because if the engobe is made of clay, it will also shrink when it dries, so it needs to shrink along with the clay piece.

Let's imagine what happens if we paint a piece that is already dry. If the piece has already dried, it means it has already shrunk and therefore will not shrink any further. The engobe, on the other hand, being clay with water, will still shrink after we apply it to this dry piece. In this case, what will happen is that the engobe will not stick well to the piece and will end up peeling and coming off as it dries and shrinks. That's why it's important to paint the piece before it dries .

It is possible that an engobe will have to be applied more than once. It may happen that after painting the first layer, you still notice the color of the clay and the paint does not provide good coverage. We must wait until some of the water comes off, that is, until the engobe loses its shine, and then we paint again. Sometimes you have to paint two or even three layers of engobe.

To avoid this situation, we paint the piece when it is still in a leather state , instead of when it is still very soft. If it is in leather condition, the surface will absorb and grip more engobe; while if it is very soft, as it has more water, it is less absorbent.

And now?

When the piece is completely dry, it is ready to be fired, becoming a ceramic piece. As mentioned, there are several ways to roast a piece. The easiest way is to take it to a ceramics studio or store that can bake the piece in a ceramics oven. And each piece is a new surprise.