Plastic clay and flower ornamentation

Lesson 1. Wedging clay in plastic form

In learning the process for working plastic clay to uniform consistency, the student must eliminate air bubbles in clay and familiarize himself with the "feel" of clay of the proper plastic texture. Lesson I will instruct him in this procedure.

Materials:

  • 1 pound of clay, plastic form, low firing, red, grey, or white
  • 1 breadboard
  • 1 paring knife
  • 1 plaster bat

Note: A plaster bat is a flat slab of plaster of Paris. Plaster of Paris rapidly absorbs moisture from wet clay which may be placed on it. This plaster bat may be purchased, or made as described in Part 2, Lesson VIII. The bat should be about 1 foot square and about 1 inch thick.

Comments: Moist clay dries more rapidly on the outside surface which is exposed to the air, with the result that the moisture content is not uniform throughout the clay mass. Therefore, before modelling the clay it is necessary that it be kneaded or "wedged" to mix all parts thoroughly.

Clay may be packed or pressed too hard at one point, making it denser as compared to other portions of the clay. This packing tends to force out the moisture in the packed area as compared to other portions. Air bubbles may be present in the clay and must be wedged out.

If the clay is too moist and sticks to the fingers or breadboard, it will collapse during and after modelling, spoiling the work already done. If it is too moist some of the moisture must be removed; the clay may be spread out on a plaster bat for partial drying and then wedged to uniform consistency. If the clay is too dry, holes or indentations may be poked into it, water added, and the clay allowed to stand until the water permeates it, after which it must be wedged to uniform consistency.

Within a very short time you will instinctively learn the feel of the clay at the proper modelling consistency. It will have the same consistency as table butter at slightly less than normal room temperature. It will not adhere to the fingers, will not flake or crumble, will be smooth to the touch, will take indentations and modelling without change or collapse, and will be quite pliable.

Explanation of techniques: Wedging brings the whole mass of clay to a uniform consistency of water and clay. When the clay dries and is fired in a kiln, the moisture inside the clay is converted to steam and is driven off; the porous "bisque" remains and may be glazed. When the glaze is applied, it enters the pores of the bisque. If one part of the clay has been packed too hard there will be fewer pores in that part which will result in a thin glaze; and the over-all finished effect after the glaze is fired in will be spotty. Moreover, if parts of the clay are not of uniform consistency, during firing there will be an uneven expansion or contraction in the hard and softer parts, resulting in warping or possible cracking and distortion of the object in the kiln.

The presence of air holes in the clay will cause a collection of steam in these holes and will result in the exploding or cracking out of the clay around these air pockets during firing.

Fig 1

Procedure: Take a double handful of plastic clay in the hands. If it is tacky or sticks to the hand, spread it out and let it remain on the plaster bat. Turn it over on the bat every 10 minutes. Test the clay from time to time to see if it still sticks to the hand. When it ceases to stick, take up the clay and place it on the dry breadboard. Spread out the clay with the hands. Fold over the clay, kneading and squeezing it as you would knead bread dough (Fig. 1A). Tear off portions of the clay, working them into the remainder until the entire mass of clay has the proper texture, is smoothly pliable, and feels the same throughout. Cut across the clay mass with the paring knife and examine the cut face (Fig. 1B). If any air bubbles or pockets show (Fig. 1C), continue wedging the clay until, upon further cutting, none appear (Fig. 1D). After proper wedging, the clay is ready for modelling or pressing into shape.

Fig 2

Tests: One: Take a small portion of the wedged clay, roll it on the breadboard with the palm of the hand until it forms a round stick about 6 inches long and about the diameter of a pencil (Fig. 2A). Bend the stick until both ends touch. Stand up the circle so formed. If the clay is too wet, the circle will collapse. If the clay is too dry, cracks will appear on the outside of the circle. If the circle holds its form and does not crack, the clay is of the proper consistency (Fig. 2B).

Two: Poke the finger through any part of the mass of wedged clay. No part should feel harder than any other; if it does, continue wedging until the clay is of a uniform consistency.

Three: Take up a small bit of clay, rub it between the thumb and index fingers. If it crumbles or breaks into lumps, it is too dry, and the whole amount will require wetting and rewedging.

Cautions: Plastic clay not in use should be stored in a bucket or earthenware pot with a lid, to seal the air and prevent the clay from drying out. Partially modelled clay, upon which it is desired to continue work later, should be completely covered with a moist cloth or airtight container to retain the moisture in the clay.

Note: Dried scraps and hardened pieces of clay should be saved in a separate container. These scraps can be pulverized when completely dry and then, with the addition of water, can be restored to plastic form.

Lesson II. Making clayflower ornaments

A considerable vogue has grown up in the making of ceramic pins and earrings for personal adornment. These are always eye-catching and attractive. Ornaments are used also as buttons for clothes, for decorating ceramic boxes, statuettes, vases, and other objects. This lesson will show how these ornaments are made, and how they can be converted for personal use or for decorating larger ceramic objects.

Various parts of these ceramic ornaments (or ceramic jewellery) may be fired with different coloured glazes to give very striking effects. Although somewhat fragile, ceramic jewellery never fades and is popular with many women.

Materials:

  • 1 pound of clay in plastic form, low firing, cream colour *
  • 1 breadboard
  • 1 rolling pin (wooden)
  • 2 half-pint empty milk bottles
  • 2 art brushes, size 7-10
  • A small piece of fine wire mesh, such as a tea strainer.
  • Several wooden orange sticks, manicure type (a set of boxwood modelling tools are inexpensive and can be used in place of the orange sticks)
  • Several pieces of triple zero sandpaper
  • A large piece of cloth preferably a towel
  • 1 paring knife or pen knife
  • A scratch knife
  • 2 pieces of oil cloth each about 2 feet square
  • 2 pieces of wood about 1/8 inch thick and 1 foot long (2 wooden rulers will do nicely)

*Note: The clay will be grey in plastic condition, and lighter grey when bone dry, but will turn to a cream colour when fired in bisque.

Comments: Clay for ceramic ornaments is generally worked into very thin pieces; so it is essential that the clay be kept fairly moist and workable at all times. As each piece is completed it should be placed under the damp towel or piece of cloth to preserve its moisture.

In making flowers, since the fingers are used in forming the individual petals, in bending and tapering the edges of leaves, fingerprints will be left on the clay. A drop of water applied with the finger, or with a clean soft brush, will make the surface of the clay smooth again; too much water, however, will soak through the clay and cause it to collapse.

In working clay with the fingers, press gently; do not squeeze it tightly or attempt to stretch it as you would dough. Squeezing or packing the clay too tightly will reduce its porosity when fired and cause spotty glazing. Clay does not have the elasticity of dough and will come apart if stretched. If the piece is to be made wider or longer, add a little more clay, wedge it in, and press gently to the desired shape.

Pasting Slip

Pasting slip is made by adding water to dry or plastic clay and mixing both thoroughly until the liquid formed has the consistency of thick cream. A glass jar of pasting slip should be made prior to commencing on part I of this lesson. It will be easier to make the slip from dry clay than from plastic clay. When made, the slip should flow smoothly and evenly from the brush when applied to moist clay surfaces. (This pasting slip does not contain water glass as does casting slip) .

To make two pieces of plastic clay stick together, pasting slip is applied with a soft brush to the surfaces or points of both pieces where they are to touch, after which the pieces are gently pressed together. Take care when putting the two pieces together. See that they are joined at the right place, as the slip will cause them to adhere at once, and they cannot be moved very much or separated without damaging or deforming either or both pieces. Use plenty of slip at the joints, otherwise the pieces may come apart when fired.

Pasting slip is used only when the plastic clay pieces to be joined are moist-never when they are dry. Slip may be applied with the brush at the seams where two pieces join, to smooth or cover the seams.

To make larger pieces adhere better with pasting slip, the areas to be joined are crisscrossed or "scored" with the knife to a depth not greater than 1/32 inch. Apply the pasting slip to both areas. When one piece is placed on the other, place the top piece at a very slight angle to the first and twist it into the correct position. This action insures a very tight and solid grasp.

In marking the veins on leaves or making other indentations in clay ornaments, do not press too hard with the marking instrument, as such action may weaken the object and cause it to break when firing. Mark lightly and gently.

In devising different types of marking, the ends of the orange stick may be shaped with a pen knife and smoothed with fine sandpaper to the desired shape. For example, the pointed end of the orange stick may be used for indentations; the wide end may be notched for raised veins on leaves if this effect is desired. The stick should be moist to avoid tearing the surface of the clay. Boxwood modelling tools may be used equally well with this plastic clay to obtain particular or special effects.

The completed clay object-when the parts are assembled and pasted together, the edges and seams trimmed and smoothed, and the desired shape arrived at-is carefully set aside to dry. After two days the smaller objects should be "bone dry," and the surfaces can be sanded carefully with a small piece of triple zero sandpaper. Large objects may take a week of drying before becoming "bone dry." In the bone-dry state the pieces are very fragile, so considerable care must be taken in handling and sandpapering.

When objects are "bone dry" they are fired to bisque. If they contain any moisture (are not "bone-dry") they will crack on firing. Numerous designs and patterns for clay ornaments are available at ceramic shops for those who desire to copy designs for beginning practice. As you advance and become more familiar with ceramic jewellery making, you should attempt to create your own patterns.

In creating original designs for flowered jewellery, it is best to get the original flower and leaves and draw a pattern, with pencil and paper, of each size petal and leaf to be used. The design to be drawn for the clay cut-out of each part should be smaller than the final desired size, because the clay will be expanded by pressing and tapering on the edges.

Part I. Making a calla lily

In the first part of this lesson we shall make a calla lily set. This is one of the more graceful and simpler flower ornaments.

Fig 3

Procedure: Wedge a handful of clay. Moisten the shiny side of one piece of oilcloth and place it on the breadboard with the shiny side down. Place the wedged clay on the oilcloth. Flatten the clay down by hand until it is about 1/4 inch thick. Roll the clay with the rolling pin until the clay is quite thin, about 1/8 inch thick (Fig. 3A). Place the second piece of oilcloth (not moistened and shiny side up) on top of the clay. Turn over the combination of the clay and oilcloths so that the top piece of cloth is now on the bottom resting on the breadboard. Holding on to the lower piece, peel off the oilcloth (which is now on top) from the clay. The clay will show the weave marks of the piece of oilcloth which has just been peeled off. This top surface of the clay is now rolled gently with the rolling pin to smooth it. Place the moist towel over the clay.

Draw the design of the leaf and petal of the calla lily in Fig. 4 on a piece of paper twice the size of that shown, and cut out these patterns with scissors. Place the patterns on the rolled clay, and, with the thin blade of the pen knife, cut through the clay following the edges of the pattern (Fig. 3B). Using the point of the orange stick, follow the veins of the leaf on the paper pattern, so as to indent the clay. Do not press so hard as to cut through the paper pattern or to make the veins too deep in the clay. Remove the paper pattern from the cut pieces of clay. With the fingers, gently taper out the edges of the petal and leaf to a fine edge. Place these pieces under a moist towel.

Fig 4

Roll the "centre piece" of the lily by hand on the breadboard to the size and shape shown in Fig. 4. Roll the top part of the centre piece across the wire mesh of the tea strainer-so that the wires are diagonal to the length of the centre piece, thus giving it a meshed surface (Fig. 3C).

Fig 5

Next take the clay petal, fold the left side over a rounded handle of the paint brush as indicated in the diagram (Fig. 5A), rolling the upper edge out. Place the centre piece under this fold, with the lower part protruding under the petal about 1/4 inch (Fig. 5B). Fold the right side of the petal over the left (Fig. 5C). Gently roll out the edge, both on the upper part and in front of the overlapping edges (Fig. 5D) . Give the point of the petal a twist. Apply some slip with a brush at the lower part of the centre piece where the petal goes around it, and press the petal gently to the stem.

Take the leaf, and give it a wavy surface toward the edges by pressing the clay forward between the veins. Score or cross hatch indentations lightly in the surface on the centre of the leaf with the knife. Apply plenty of pasting slip with the brush, on the back of the petal, and along the centre vein of the leaf. Carefully place the petal on the leaf in proper position. The slip will cause the parts to adhere at once. Fig. 4 shows the assembled pin.

Set the assembled ornament in a safe place to dry. After two days the ornament should be ready for firing. This ornament is most attractive when glazed with brilliant green for the leaf, white for the petal, and yellow for the centre piece.

Patterns are included in this lesson for earrings. These may be of the flower only, or a leaf may also be used if desired. The procedure is the same as that for the pin, except that the pieces are smaller and require quite delicate handling. However, with a little practice this will come easily.

Precautions: When rolling over the edge of the calla lily, never squeeze the clay around. Roll it around the index finger with the thumb; or roll the edge around a round pencil with the finger. Again, never squeeze the edge of the petal. This precaution about not squeezing the edges of the petals applies to all clay ornaments.

Part II. Making a wild rose

In the second part of this lesson we will make a wild rose pin and earring set. This set is selected because it illustrates a variation in the method of making ceramic flowers (Fig. 6).

Fig 6

Materials:

Same as for part I plus:
A round pencil, flat on the top (no eraser)

Procedure: Wedge a handful of clay, and roll it to Vs inch thickness as described in part I of this lesson. Draw on paper the leaves and petal designs twice the size shown in Fig. 6, cut out with scissors, and place on rolled clay. Cut out of the clay the leaf and petal groups in the shapes indicated. Gently taper the edges of the leaves and petals. Do not squeeze the clay tightly. Mark the veins on the leaves lightly with the point of the orange stick. Pass a wet brush lightly over the pieces. Place the pieces under a moist towel.

 

Fig 7

Roll a ball of moist clay to about 5/8 inch in diameter. With the thumb, force this ball of clay through the mesh of the tea strainer (Fig. 7A). The clay will appear on the other side of the strainer like a cluster of worms or stamens. Pass the thin blade of the pen knife along the surface of the strainer under the clustered clay (Fig. 7B). Take out the petal group, place it on breadboard, and apply pasting slip to the centre. Carefully place the clustered clay in the centre of the petal group (Fig. 7C).

Now, with the flat top end of the pencil, press down on the centre of the cluster, flattening a circle about 1/2 inch in diameter. Taper the flat button formed in the centre slightly to the edges with the pencil top, or with the flat side of the orange stick. Avoid touching the stamens, as the button is being shaped (Fig. 7D). With the point of the orange stick stipple the surface of the button (Fig. 7E).

Shape the petals with the fingers by turning them up, higher in the middle, and cupping back toward the sides of each petal (Fig. 7F).
Apply slip to the back of the petal group on the circle between the leaves. Place the petal group on top of the circle as indicated (Fig. 6C).
Roll the leaves gently to give them a natural shape. Set the assembly out to dry. When the assembly is "bone dry," it is ready for bisque firing and subsequent glazing.

The earrings are made by the same procedure as the pin. The pieces arc smaller and require more delicate handling. However, do not squeeze the petals or leaves tightly in tapering, or rolling to natural curvature.

Comments: The use of the stamen cluster, formed by passing clay through the mesh of a strainer, has application to all kinds of flowers having this kind of stamen formation.

Part III. General rules for making ceramic flowers

In this part, we shall indicate several methods of imitating various portions of flowers for ceramic ornaments.

Making centres for flowers: To obtain a more realistic effect for some flowers, flatten the ends of the individual stamens or pistils by a gentle squeeze at the tips with the fingers or tweezers. In some instances tiny balls of clay can be rolled by hand and clustered together to form the centre. For flowers with a closely compacted centre, a button of clay can be formed by hand, and stippled with the point of the orange stick (Part II of this lesson). Added realistic effects in this stippling may be obtained by shaping the orange stick with a piece of sandpaper, to a triangular or four-sided point. If desirable, the rounded side of the button can be rolled across the surface of the tea strainer to obtain a pebble-grain effect (part I).

Working petals and leaves of flowers: Individual petals may be cut out of the clay from patterns, tapered to the edges, flared out, and cupped by the fingers as indicated in the two preceding parts of this lesson. With a little practice, the clay may be cut by eye, without a pattern, to the approximate shape of the petal; then the petal can be cupped, flared, crimped, or rippled to its natural formation. Rose petals, for example, may be cupped around the curve of the thumb. Some petals, such as those found in carnations and leaves, have jagged edges; these can be reproduced by cutting the top and side edges with the point of the pen knife held flatwise, or by biting out bits of clay with pointed tweezers.

Do not attempt to make petals and leaves as thin as in nature. In the widest part they should be from 1/8 to 1/16 inch thick to be self-supporting and to avoid cracking or warping on firing. They will appear quite satisfactory after glazing, even when thick.

In making a bell-shaped type of petal, such as a morning glory, the pattern is a circle with one sector cut away-like a pie with one piece cut out. The clay is brought up to form a cone with the edges of the pie cut overlapping. These overlaps are slip-pasted together and pressed and smoothed by hand or the wooden orange stick to make a perfect cone. The cone may then be flared out, trimmed, and vein-marked to imitate the real flower shape.

For smaller bell or conical shaped flowers, the pointed end of the orange stick may be inserted in the center of a small piece of clay, and the stick rotated from the upper end, meanwhile pressing up the clay with the fingers to form a small cone. The upper edges are tapered by hand (never squeezed), trimmed to size, flared, and veined as in the larger flower. The centre is slip pasted in, and the flower mounted on its leaf or leaves.

For cup-shaped petals, the larger flowers may be made in the same way as the bell-shaped, except that the base is flattened and rounded out, before flaring, trimming, and veining. For the smaller cup-shaped flowers, instead of using a pointed orange stick, a rounded-end stick is used, over which the clay is moulded, then trimmed and veined.

Leaves should always be gently veined to look natural; avoid deep cutting to prevent splitting during shaping, drying, or firing. In nature, leaves are seldom seen perfectly flat, and thus, after tapering and veining, they should be waved, or indented by hand to resemble the real leaf as nearly as possible. Where flowers are to be mounted on top of leaves, the area on the leaf where these will be slip-pasted together should not be veined, but should be scored (not too deeply) with the knife to provide for more contact surface.

The edges of certain type leaves should be trimmed and notched to correspond to the natural leaf while the leaves are still flat, prior to waving.

Part IV. Applications of flower ornaments

Ceramic flowers may be used as pins and earrings as mentioned before. They may be made and slip-pasted while moist to ceramic cigarette, candy, or cosmetic boxes; to ash trays, open bonbon dishes, bases of statuettes, and the tops or sides of vases. Large assemblies of flower groups may be made for table centrepieces and candlesticks.

In making certain types of ceramic buttons, a circle the size of the desired button is cut in clay, upon which the flower assembly is slip-pasted. After bisque firing, the back side of the button is not glazed; only the front parts are glazed. After the second or glaze firing, a metal loop is cemented on the back side of the button, for sewing to the dress or coat. Another method for making certain types of ceramic buttons is explained in part IV, Lesson VIII.

Fastening bar pins, ear screws, and ear clip to ceramic ornaments. Bar pins for ceramic pins and ear screws or ear clips for ceramic earrings are sold in ceramic supply houses. They are either of metal or plastic material. These items have a flat portion by which they can be cemented to the ornament, using any of the various kinds of metal, china, or similar household plastic or composition cement. Do not use mucilage.

hen the ceramic pieces are in bisque form, locate the position on the ceramic pieces where these items are to be cemented, and draw larger circles in pencil thereon. When glazing, do not apply glaze inside these circles. After the glaze firing, apply a drop of plastic cement inside the bisque circles and to the flat portion of the pin, clip, or screw. Wait until the cement becomes somewhat "tacky." Then press the flat portions against the bisque and hold for about 5 minutes. Let the pieces dry. These "backs" will adhere very strongly to the ceramic pieces.

The reason the areas are left unglazed is-plastic or composition cement adheres very strongly to bisque, but very little to glaze.


Ceramics:
  • Index
  • Coil method
  • Decoration
  • Glaze decoration
  • Glossary
  • Hand pressing
  • Kiln & firing
  • Mould making
  • Plastic & flower
  • Potters wheel
  • Slab method
  • Slip casting

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