Coil method of making ceramics objects

The making of ceramic pieces by the coil method is a technique which you should master. Unique, original models can be constructed by this method which cannot otherwise be duplicated. In addition, the coil method makes for valuable experience in handling and mastering the manual manipulation of plastic clay. Parenthetically, this method is one of the most ancient known to men, for the manual building of clay objects.

At first, objects constructed by the coil method may appear somewhat crude. But with a little practice very competent work can be accomplished. Some of the proper actions and precautions are indicated here.

Fig 15

Wedged clay is rolled on the breadboard with the palms of the hands only (Fig. 15A). If the fingers are used at all in the rolling it will be almost impossible to get a uniform "snake" of clay.

In rolling the clay, roll it back and forth under the palms on the breadboard beginning at the centre of the clay slug. Do not roll the clay over and over in the same direction. Use a light, quick, back and forth motion with the palms and do not press too hard. Remember, clay is not elastic like dough, and it will stretch or twist only a little. If it is stretched or twisted too much, the "snake" will break or come apart.

Clay, while being rolled, is kept slightly more moist than its normal moisture content. At frequent intervals while rolling the clay (every minute or so), dip the fingers in a bowl of water and run the moist fingers across the top of the snake to keep it moist.

When rolling the clay, work the hands outward along the snake (Fig. 15A). The snake, when finally rolled out, should be about 1/4 inch in diameter. For small objects the snake may be as little as Vs inch in diameter; for quite large pieces the snake may be as much as 'A inch in diameter. It is not necessary for the snake to be exactly 1/4 inch all along its length. An approximate diameter is sufficient.

Objects made by the coil method may be smoothed with a modelling tool, after being assembled, on both the inside and outside so as to give smooth surfaces, if desired.

When splicing the end of one snake to the next, do not cut the ends of the snakes straight across and attempt to slip paste them together. Cut the ends at a long slant, apply pasting slip to each cut, and wedge them together by pressing and rounding with the fingers (Fig. 15B). If a long continuous snake is desired for some models, the ends of two snakes are cut at a slant, slip pasted together, and rolled together on the breadboard.

In building up a bowl or box by the coil method, if you wish to expand the size as the object builds up, run the upper coil slightly to the outside of its next lower coil. If you wish to make the object taper inward, run the upper coil slightly inside of the next lower coil.

When the object is built up, apply thick pasting slip on the inside at all points where the coils touch, to insure that the coils do not come apart when firing and to further strengthen the object.

Let us proceed with lesson IV.

Lesson IV

Materials:

  • 1 pound of clay, in plastic form, low firing, any colour, well wedged 1 breadboard
  • 1 rolling pin
  • 1 pen knife
  • 1 modelling tool
  • 1 half-pint bottle of pasting slip
  • 1 art brush, size 7 to 10
  • 1 large piece of cloth
  • 1 paring knife
  • 2 pieces of oilcloth, 2 feet square, each

Comments: Our first exercise is the making of a cylindrical cigarette urn. This is one of the simplest objects which can be made by this method. In the second part of this lesson we will make a lidded box. In the third part of this lesson we will make a type of woven basket. The practice resulting from making these objects will give you excellent experience and indicate the many possibilities in plastic clay.

Part I. Making a cigarette urn

Procedure: With the rolling pin, roll out a small slab of plastic clay to 1/4 inch thickness, on the breadboard, as described in Lesson III. Cut out a circle of clay 3 1/2 inches in diameter, by drawing a circle on paper, cutting it out with scissors, placing the circle pattern on the clay, and cutting out the clay with the pen knife along the pattern. This circle will be the base of the cigarette urn.

Take a handful of clay and roll it between the palms until it forms a cylindrical slug about 1 inch in diameter. Wet the shiny side of the piece of oilcloth with water so that it will adhere to the breadboard. Place it shiny side down on the breadboard. Place the cylindrical slug on the oilcloth, and, with the palms of both hands, roll the clay back and forth, working from the centre out (Fig. 15A). Roll the clay until it forms a long snake 1/4 inch in diameter. Taper one end of the snake to a fine point.

Fig 16

Place the base of clay on the oilcloth (on the breadboard). Apply slip paste on the outside 1/4 of an inch on the top of the base around the edge. Flatten the tapering end of the snake to a long, slanting wedge shape. Feed the snake around in a circle on top of the base with the right hand, supporting the coil with the left hand (Fig. 16A). Splice additional snakes as needed. Build the coil straight up for a height of 4 inches. The coil on the top should be tapered and flattened so that the top is exactly level. As the snake is wound, slip paste each turn, so that the turn above will adhere to it. Press down slightly each turn on the next lower turn.

Apply thick slip paste on the inside all along between the turns where they touch. There should be no air gaps between the turns. Set the urn to dry.

We will now make the lid to the urn. Taper one end of the snake and flatten it as before. Starting from the centre, wind up a coil moving it across the breadboard until the flat coil is about 3 inches in diameter. Taper the snake flat toward the end, and bring the end in, to form a perfect circle 3 inches in diameter (Fig. 16B). With the fingers underneath, lift the centre of the coil up so that the top curves out and down from the centre (dome-shaped) (Fig. 16C). If handy, a smooth playground ball may be used in forming the curved surface by placing the flat coil on the ball and gently pressing the outer turns down. Do not flatten the coils when pressing down. If the lid is too large, part of the coil must be unwrapped, and tapered in toward the end, until it appears that the lid will fit over the urn. Now, with the lid upside down in the cupped palm, apply thick slip all over the inside of the lid, especially where the coils join. After the slip has dried slightly, a dry ball of clay is placed underneath the lid to keep it from sagging. Let the lid dry for about one-half hour.

We shall now make a handle for the top. Make the loop as illustrated and cut the contact length 1/2 inch from the loop, squarely across the ends (Fig. 16D).

Hold the handle vertical, apply slip paste to the bottoms of the contact lengths, and on the top of the lid, where they will touch; and slightly press them together in place. The lid should be drier than the handle when the handle is pasted to it. Set the assembly out to dry for bisque firing.

Hints: After the urn is formed and while it is still plastic, correct the shape, if it becomes distorted, with the palms of both hands.

Correct any marks, flat spots, or surface imperfections with fine sandpaper after the object is bisque fired.

Part II. Making an oblong box

Materials: Same as for part I.

Procedure: By the slab method cut out 2 flat pieces of plastic clay 3 1/2 inches by 4 1/2 inches by 1/4 inch thick (Fig. 17A). One will be the base of the box, the other will be the top.

Fig 17

Roll out a snake of clay 1/4 inch in diameter as described in part I. Cut the starting end at a slant, place it in the middle of a side, and run the snake on top of the base, all around the outside border of the base. Cut the snake with the the same operation with the second loop as with the first. Wedge the second loop slightly on the inside against the first loop. Continue adding loops until the height of the box is 31/2 inches high (about 10 to 12 loops (Fig. 17C). With the brush apply slip paste around the outside of the box, between loops. Set the assembly in a place out of direct sunlight or air draft to dry.

Place the top plate on the plaster bat for about 10 minutes on each side, to dry it. A semi-loop handle, a flower ornament, or bow knot may be slip pasted on top.

Carefully measure, without touching the coil box, the inside dimensions of its top loop. Roll a short snake about 3/16 inch in diameter and run it parallel to the edges on the bottom of the top plate, inside the measured dimensions. This loop will be the retaining rim for the top plate (lid). Slip paste this loop to the bottom of the top plate. Place dry balls of clay 1/4 inch in diameter under the edges and centre of the plate to prevent it from sagging while drying, and to prevent crushing the retaining loop (Fig. 17D).

Set the assembly out to dry for bisque firing.

Hints: In slip pasting ornaments or the retaining rim to the top plate, make sure they are always more moist than the plate.

After the box and lid are bisque fired, the lid may be fitted on the box. If the retaining rim is too large, sandpaper the sides of the rim down to a better fit.

Part III. Making a Woven Basket

Materials: The same as in part I.

Procedure: Roll and cut out a clay base 6 inches in diameter and 1/4 inch thick. Roll a snake, and from it cut 13 sticks about 4 1/4 inches long. Set the sticks vertically on top of and along the outside of the base, spaced evenly around the circle. Slip paste and wedge them to the base. Bend the sticks in an outward curve (Fig. 18A).

Fig 18

A large circular mound of fairly dry clay can be formed around the outside of the sticks before beginning to weave in the snake. This coil will preserve the shape of the basket as it forms and will support the sticks as well.

Roll a long snake, tapering at the beginning end, as in part I of this lesson. Beginning between one pair of sticks, feed the snake inside one stick, then outside the next stick, then inside the next stick, and so on around the circle (Fig. 18B). Do not pull the snake, or tighten it against the sticks. Feed the snake so that it lies snugly against the sticks but does not exert any pressure on them. If the sticks bend too much, straighten and restore them to former position. Feed the snake with one hand while supporting the sticks with the other.

Splice each snake to the next snake by pasting and wedging before feeding around the basket.

Feed the snake inside of and around the sticks until the basket is about 3 1/2 inches high. Adjust the basket with the palm of the hands around the outside of the turns, so that the basket is perfectly round and curves out smoothly. Trim the sticks with a pen knife so that they are perfectly level across the top and even with the top of the top turn.

We shall now lay a twisted double snake around the top of the basket. Remember, clay will not stretch. So in effect we will be folding rather than twisting two snakes around each other. These instructions for twisting a double snake apply to twisting coils for any purpose.

Place the lengths of two snakes alongside one another. Lift up one end, and with the fingers of the other hand turn the lengths around one another, without squeezing them together. Move the supporting hand forward as the twist is made. The twist is made by the fingers at each point, and not by one twist causing another twist farther along (Fig. 18C). The use of twisted double snakes is used extensively for making handles for cups, vases, and other objects.

Apply slip to the top turn and the stick tops. Lay the twisted double snake squarely on top of the stick tops. Where the circle of the twisted snake comes around to meet itself, cut the individual snakes at a slant, slip paste and wedge them together-being sure to preserve the appearance of a continuous twist in the double snake. Apply pasting slip to the inside of the basket to all points where the coils touch each other and the sticks.

Hint: In making ceramic weaving, there must always be an odd number of sticks.


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