There are a number of methods of working in clay. The simplest are described here, and projects using some of the methods are given in this chapter.
This method is the shaping of figures and other small articles from a mass of clay. This provides great freedom of activity and creativity, and is one of the steps most enjoyed by beginners. Something as simple as a snake or a toadstool or a roly-poly man may be the first figure, leading up to figurines of animals or people (Fig. IV-7).
This method consists of building sides on a base by adding coils of clay joined together by smoothing while the clay is soft. The making of a bowl may call for a template to use as a guide in keeping the shape uniform (Fig. IV-8).
This method employs a wooden slab, rolling pin, and guide sticks to roll out the clay in a flat piece. The guide sticks are used to obtain a piece of clay of the desired thickness. Sometimes a wooden frame is used to make a base or tile of desired proportions (Fig. IV-9).
This method makes use of a mold of plaster to make specific shapes or design, or to repeat designs. The mold is carved from plaster with improvised tools. This method is often used in making camp pins or symbols (Fig. IV-10).
This is a method of carving a piece of clay in a free, standing form. It is related to modeling, but the clay is drier when worked, and the work is done with modeling tools or knives (Fig. IV-11). Plaster of paris blocks are sometimes used as the carving material.
Articles made of clay may be decorated by a number of processes, such as these:
By this method some of the clay is removed from the surface, either leaving the design raised, or cutting the design into the clay, leaving the background raised (Fig. IV-12). This is done when the clay is leather-hard, but not bone-dry, before the piece is fired.
1. Make the article ready for decorating-leather-hard, but not bone-dry.
2. Make a design on paper, basing it on size and shape of article to be decorated.
3. Place paper design on the clay, and go over lines with a hard pencil or pointed hardwood stick, inscribing the design on the clay.
4. Go over the design in the clay with a modeling tool or sharp stick or large nail, making the grooves and areas deeper in the clay (Fig. IV-12a).
5. If the design is to be raised, use knife to cut away background, and use modeling tool to smooth edge (Fig. IV-12 6).
This is an Italian word meaning "scratch," and this method is one of scratching or inscribing a design on a coating of slip, so that the design shows the original color of the clay.
1. Make the article and let it dry to leather-hard firmness.
2. Plan design on paper.
3. Cover the article with slip of desired contrasting color. Let it dry enough so that it can be scratched without running. Inscribe the design with tools as for incised design, scratching off just enough of the slip to show the basic color underneath (Fig. IV-13).
4. Dry, then fire.
This method consists of painting the article with slip of paint consistency. The slip is applied to an article at the leather-hard stage; the article is then bisque fired, glazed with light or transparent glaze, and fired again (Fig. IV-14).
Embossed designs are those in which clay has been added to the original piece, so that the design appears raised on the surface.
1. Make article, and let it dry until a little softer than leather-hard.
2. Plan design, and cut pieces from 1/4" thick strips of clay.
3. Lay these pieces in place, then work into background surface, using slip and a little water to smooth the embossing pieces on to the surface (Fig. IV-15).
4. Let dry, and fire.
5. Apply glaze, as desired, and fire again.
This is a method of coating the article with a shiny surface. The glaze may be transparent, or in many varieties of single colors. A colored design may be applied. The simplest glazing is a coat of glaze which is brushed on the article after the bisque firing (Fig. IV-16). With a second firing, the glaze melts and forms a glassy coating on the clay. There are many different types of glaze; each calls for a specific heat to be used in firing. For such projects, consult one of the references in Books to Help at the end of the chapter, or follow manufacturer's directions.
For firing in a primitive kiln, a simple formula for a low-fire glaze is used.
Decorating Self-Hardening Clay
Objects made of self-hardening clay may be painted with poster paints, then painted with a transparent liquid glaze or shellacked. Glaze or shellac may be applied directly to the object.' It will then be hard and waterproofed.
Articles made of clay must be dried and baked for permanence. The baking is done in an oven or furnace known as a kiln (pronounced kill). The articles to be baked are known as green ware before firing, and as bisque or biscuit ware after the first firing. The second firing, following glazing, is known as glost firing.
Kilns may be wood burning, gas or electric. In camps it is possible to construct a wood-burning kiln that will do an adequate job of firing. There are many references for building this type of kiln. Two of the most helpful are Arts and Crafts with Inexpensive Materials and Pottery Made Easy.
The simplest type of primitive kiln is an iron pot turned cover the objects to be fired (Fig. IV-17). A fire is built around the pot, and slowly increased in intensity until the pot is covered with the fire. The fire is kept burning for several hours (up to eight) and then allowed to cool off slowly. As in all firing, the fire's heat is gradually increased, and then after prolonged heating, the kiln is cooled off. Sudden changes of temperature either of heating or cooling may cause the clay objects to crack and break.
A more permanent and more satisfactory primitive kiln is made in a pit (Fig. IV-18). The pit is lined with stones or fire brick, to hold the heat of the fire. The clay articles are put in an iron kettle or similar heavy container with a cover. The fire is built of hardwood and allowed to burn to coals. The kettle is lowered into the pit, with objects to be fired carefully placed inside. The cover is left slightly ajar to allow evaporation. When the kettle has warmed from the coals, the fire is rebuilt around it, and on top of it, and kept burning from five to eight hours, then allowed to die out gradually.
Another type of primitive kiln is built in a bank (Fig. IV-19). The hole is dug in a spot protected from the wind, and is made deep enough to more than accommodate a large can, placed on its side. The bottom of the hole is lined with a layer of stones to be heated (watch out for rocks that cannot be heated), and a base for the can is made of stones or firebrick. Shelves of wire screening should be placed in the can to hold the clay articles.
A fire may be necessary to dry out the ground before the real heating begins. The can is placed on the supports, and the ware stacked in. Cover is placed lightly on can- not tightly.
The fire is kept going, and gradually increased until the can is red hot. It is kept at red-hot heat for several hours, then allowed to cool off gradually. When can is cool to the touch, it may be opened-but not before.
The success of wood-burning kilns depends upon a good supply of hardwood and upon constant attention during the whole operation. The fire should come up gradually to its peak, and be kept that way for several hours. This process consumes the better part of a day, as well as plenty of wood, but it cannot be hurried. It is a good project for older campers to carry out; relays of fire tenders may be organized, and other craft or skill activities may be in process during the burning.
Primitive kilns are not satisfactory for baking glazed articles, as there is no way of controlling the temperature of the fire.
Gas or electric kilns may be installed in craft centers, or green ware and bisque may be fired at commercial kilns in town. For the camp that has an extensive ceramics program, either of these methods of having objects fired will be satisfactory. For campers who are interested in a total craft experience in clay, the making and using of a primitive kiln will be a rewarding experience, in spite of the amount of wood consumed and the amount of work involved.
Placing ware for firing: All clay must be absolutely dry before being fired. Cracks that may appear in the ware while drying should be mended with slip, and the article dried again.
When stacking a kiln, put largest pieces on bottom shelves, and do not let pieces touch one another (Fig. IV-19). Small pieces may be set inside larger pieces without danger.
Finishing articles: Articles may be sanded with steel wool or fine sandpaper after bisque firing, to produce a smooth surface.
Some clays may be made nonporous by rubbing with wax. This is true of roughhewn articles that are not glazed.