The wooden modelling tools,
The rectangular tool of sheet steel,
A large hoe-shaped tool,
A large kitchen spoon.
Having chosen the bowl that you wish to copy, dust it with a cotton cloth in which ground flint is tied, and roll out a piece of clay two or more inches larger in diameter than the bottom of the bowl, and about an inch thick. Press this carefully into the bottom, making sure that it touches everywhere. Now roll out several other pieces of the same thickness, large enough to reach from the upper edge of the bottom piece to the rim of the bowl, and four or five inches wide. The upper edge of the bottom piece having been cut even and wet with slip, these pieces are pressed down firmly and joined to it with the nail stroke before mentioned. Great care is also taken to press these pieces against the sides of the bowl. When the bowl is lined in this way with a coating of clay an inch or more in thickness at every point close against its walls, the clay is smoothed evenly on top, on a line with the rim of the bowl (using the rectangular tool of sheet steel) and set outside to harden.
When somewhat firm, the bowl is filled in with clay until only a space the size of a man’s hand is left in the middle. It is then set away, this time over night, to harden.
The next day the clay will have dried and shrunk sufficiently to enable the potter to slip it out of the mould. Any cracks or hollows that may be found on the outside are wet with slip and filled in with clay of the consistency of the piece. After the clay is quite dry, the form of the mould should be made perfectly true by hand (using the oval sheet-steel tools) or on the wheel. If the latter method is chosen, place the clay mould bottom side up on the wheel, centre it (according to the directions in Chapter III), and, taking a large hoe-shaped tool, hold it firmly, bracing the hand still better with a stick laid across from a plaster mould, or other convenient object, on the table, to one’s lap. Having set the wheel in motion, hold the dull point of the tool so that it just touches the wall of the mould, near the wheel. Move the point up very slightly with each revolution of the wheel—this will trim and perfect the sides. The bottom is made even in the same way. Now wash the wheel outside of the mould carefully and oil it with olive oil. Take a piece of heavy oilcloth, about eight inches wide and long enough to reach around the wheel, overlapping about a foot. Placing it with the right side in, draw it tightly and fasten with clothes pins (see [Fig. 33]). Next tie a rope or stout cord around the oilcloth, about on a level with the wheel, and, to make it more secure, wedge it with a piece of wood. Roll strips of clay about the diameter of a lead pencil, and stop the cracks where the oilcloth overlaps, also between the oilcloth and the wheel, very carefully, so as not to touch the clay mould. Be careful, from now on, not to move the wheel until the mould is made. Now mix your plaster of paris, as follows: Have an empty basin or dishpan, large enough to hold the quantity necessary for the mould—you will learn to judge this pretty well by eye. Put in as much water as you will need, and sift gradually into it, by the handfuls, the dry plaster, pressing out all lumps; in this way the water will reach every particle. When there is a small island of plaster, about an inch above the surface of the water, there will be enough. Let the plaster get thoroughly saturated by the water, as it will in a few minutes; then mix with the hands or a large spoon until it is the consistency of thick cream. Pour it gradually around and over the clay mould, not all in one place, until it is about an inch and a half or two inches above the bottom of it. Let it set for an hour or more until it seems perfectly hard. The oilcloth is then taken off, and with the dull point of the hoe-shaped tool the bottom is trimmed true on the wheel, in the same way as the wheel-made pottery is finished. The sides should also be smoothed and made even with the straight-edged sheet-steel tool. It then looks like a great frosted cake. When the plaster is hard and set, the mould is taken from the wheel and reversed, so that the clay may be removed. To do this, dig out the inside of the clay mould with a large sheet-steel tool, taking care not to come near the plaster, which would be injured by the steel. The shell of clay remaining can be easily lifted out with the fingers.