Welcome to my first part of the series!
My goal is simple. To eliminate barriers to learning. To push ourselves to be better, and to learn things we wouldn’t normally learn. We’ll start with ceramics and will cover specifics. After ceramics, or perhaps at random, we’ll introduce different topics.
Clay
Clay is everywhere, yet it’s special in its own way — it’s what makes ceramics happen. It’s the heart of ceramic arts. It’s super important for any ceramic artist to know how to work with it.
So often, clay is mistaken for soil — a blend of clay, sand, humus (partially decomposed vegetable matter, not hummus, the food either) and a variety of other minerals. Fascinatingly, compared to other materials in the earth, soil is only a fraction of the thickness — ranging from several inches to a foot!
There exist large areas of land which lack soil, such as the diverse desert and mountain regions. Beneath the soil lies an even thicker layer of subsoil, which is composed of an intriguing mix of clay, sand, and gravelly minerals! To further understand how large beds of clay are formed, let me give you a quick overview of the formation of this layer of subsoil.
Clay Formation
One is left to wonder about the process of erosion — how it has had such diverse effects and has taken place in so many varied ways across the surface of the earth. The two most eminent agents responsible for the creation of clay beds were the thawing and migration of the ice sheet during the glacial epochs, as well as the organic acids discharged from the decomposition of vegetation.
How curious it is that, as the earth cooled from its fiery origins, a rocky outer crust hardened, while internal pressures and volcanic eruptions created the grand sites of mountainous areas. It’s almost as if the earth planned it that way… and then, eventually, water vapor formed, and an atmosphere evolved above it! Truly, the earth is an extraordinary being.
The rains and winds caused erosion, while the sweltering heat and frigid temperatures caused expansion and contraction of the earth’s surface. These dual forces caused the exposed rock to fracture and crumble. Fascinatingly, the initial composition of this rock differed greatly from place to place.
How does this relate to clay formation? Well, have you ever wondered where clay comes from? It’s a fascinating process. It turns out that clay is the result of the breaking down of feldspathic minerals commonly found in granite. They are composed of sodium, potassium, alumina, and silica — all elements that have an alkaline nature. Pretty cool, huh?
Rocks decompose by being broken down into smaller and smaller combinations of alumina and silica particles as the alkalies are slowly drained from the stone. The most prized clays for potters are primarily composed of the mineral kaolinite — how incredible!
Kaolinite particles are incredibly tiny. They’re practically microscopic — measuring less than 2 microns across! That’s minuscule in comparison to the size of a grain of sand — .002 inches in diameter. They don’t have the same granular structure — instead, they stick together.
These particles have the intriguing ability to both support one another and slide when wet, allowing clay to become a malleable and useful material! It seems that the water molecules situated between the clay platelets not only help facilitate their smooth gliding past each other, but their electrical interactions also bind the platelets together.
Most clay found in the earth doesn’t contain enough kaolinite to make it plastic, and almost all clay has some impurities. These intriguing impurities and slight formula variations explain why there are so many different types of clay, each with their own unique characteristics.
Exploring the Wonders of Clay for Sculptors and Potters
Have you ever wondered how potters manage to fashion such beautiful creations out of clay? It turns out that the clay must first be cleaned of all stones and roots, and even then it is not always ideal! It has been a long-standing practice to add other materials to clay to enhance the product; this tradition dates back to the very beginnings of ceramic-making.
It all starts with the clay body, a unique combination of various clay and other materials that come together to form an easily workable material. Porcelain, for example, is composed of kaolin, feldspar, and silica, just like many of the other clay types used. Fascinating, isn’t it?
Why is it that potters gravitate more towards clays that are smoother and more malleable, which can be shaped and formed when used on a potter’s wheel? Conversely, sculptors usually favor clays that are rougher, with more texture and less elasticity, in order to prevent any issues that may arise when drying and firing bigger pieces.
Have you ever wondered why ceramic wares crafted in a certain region can differ so drastically? It turns out that the type of clay available in a local area often plays a major role in determining what is made. Before the emergence of cheap transportation and mined materials, geography was a major factor in the types of pottery produced! It’s remarkable that the earth can have such an influence on our ceramic heritage.
What makes porcelain so distinctively pristine and white? It is the rare clays required for its creation, and its need for high firing temperatures, which have kept it exclusive to a select few potters worldwide until quite recently.
The temperature range for naturally-occurring clays is quite fascinating; they are sometimes referred to as ‘low-fire’ (earthenware) or ‘high-fire’ (stoneware and porcelain). What a curious range of temperatures! How about the relatively new midrange clays? This type of clay lies between two extremes in terms of temperature, and its properties are quite sought after!
We’ve just scratched the surface in understanding clay; next up we’ll explore the different varieties, their applications, and when it’s best used. I’m sure we’ll uncover some interesting facts in our upcoming post!
A special shout out to Ceramics: A Potter’s Handbook, for the rich material.
Nelson, G. C. (2002). Ceramics: A potter’s handbook (6th ed.). Holt, Rinehart, and Winston.
Hey all. My name is Warren, which is defined as a collection of rabbit holes. It turns out, I live up to my name.
I started writing this because I took up pottery. I knew that for me to be the best I could be when throwing pottery, I’d have to do more than just hands-on work. I’d need to learn about it.
To my disappointment, there was nothing out there that simply explained pottery to my liking. I didn’t need the frills, catchy titles, or fluff. I just wanted something to help me grow in my chosen field. That’s where this was born.
My goal for us is to be able to learn a variety of topics that we wouldn’t normally go out of our way to learn. I can’t tell you how many times I discovered something I thought I wouldn’t like, only to learn of my love for it. If you’ve made it this far, you should probably go ahead and follow, and we can fall down the rabbit hole together :)
