Working with Clay – Ceramics
Working in clay is one of the most interesting and expressive things an artist can do. There is a universal feeling of making “something” from what appears to be “nothing,” and it is great to have successes with that type of creative process. Clay is, however, far from “nothing.” It is a very precise combination of materials that when joined together with moisture is a wonderfully plastic and malleable material.
Clay formulas vary greatly in the degree of smoothness or texture they possess. Porcelain, for instance, has nearly no grit within the formula, so the surface will be smooth and sleek for glazes. It is also fired to the highest temperatures to achieve vitrification. Porcelain clay is usually a very light color of gray or pure white once fired.
Earthenware clay is the other extreme. It is more porous, has much more texture and glazes are less fluid on the earthenware surface. Colors range from tans and yellows to rich browns and reds. It is easier to manipulate than porcelain but not as smooth or “polished” in appearance.
Between these two extremes is stoneware clay, the most popular. The composition of stoneware offers a more rigid and stronger base than that of earthenware but not as “tight” a surface as porcelain.
All three clays can be shaped/formed in the same way – hand built, slip cast or thrown on the potter’s wheel. In liquid form (slip), all can be cast into molds for rapid and exact duplication of shapes and forms. Of all choices of manipulation, hand building is the method used most by potters who want to offer creative and expressive forms for sale. Throwing on the potter’s wheel is fun and is a skill that can be worthwhile to learn. For the creation of large forms the potter’s wheel is very valuable. However, most potters agree that once the mechanics of throwing are learned, it is far less rewarding than the ability to create one-off items with hand building.
As in clay bodies, glaze formulas are a very precise measurement of components. Some of the elements in a glaze help hold it on the clay body. Some make glazes flow and intermix with the colorants. Some of the colorants can react with the other components to create an ever-changing array of glaze “activity.” Potters want to have a regiment of glazes that they can depend on and that will perform well and as expected. That final step is vital to the success of any clay artisan.
Methods of glaze application are as varied as there are potters. The order in which multiple glazes are applied can affect the result in new and unexpected ways. That is not a bad thing. New can be good. Some colorants react to a minor change in glaze composition to give a huge range of colors with a very slight change in formula. For those who are less interested in experimentation or study, there are hundreds of very controlled and beautiful glazes where all that is required is to open a jar and apply the glaze. Easy can be good, too!
One can brush on glazes, singly or in layers. Designs can be painted over a base glaze to create a completely new look. Dipping is a choice of many clay artisans because in one dunk you cover the entire surface. The base of a piece of pottery must be clear of glaze or it will stick to the kiln shelf. If you dunk, you either have to put on a wax-type resist to avoid the glaze coating or wash off the base. Airbrushing glazes is a very fast application method, and if applied one over another, you can create totally unique colors and textures. Even in the method of application, there are dozens of choices, so change can be a vital part of the learning process with clay and glazes.
Carving through glazes to create designs that will show the original color of the clay is also popular. Any tool can be used that will render an area large enough to detect once the glaze is fired. Runny glazes are obviously not a good choice if you want your carving to show.
Two methods of firing clay are practical for most potters: electric or gas firing. Electric is easiest but is a bit limiting because of the oxygen-rich environment. Gas firing uses this lack of oxygen to create red glazes with copper based glazes but also fires any glaze well. Gas draws oxygen from the clay body, through the glaze and transforms copper from green to red. Pretty amazing, but if reds are your passion you can get them with electric firing by purchasing ready-made glazes in red. Occasionally you will find an artist who does wood firing. That is a wild and interesting way to fire clay but not very practical for the average potter. The kilns are huge and massive amounts of wood are needed.
This article barely scratches (carves!) the surface of clays and glazes, but once an artisan becomes interested in the practices, designing and—dare we say—chemistry of pottery, it is one of the most engaging and creative ways to express one’s artistic abilities. If you get an opportunity to try any part of the clay experience – take it! Visit www.amaco.com for all your material/equipment needs from clay to kilns .