In the method of building by pieces no rolls are prepared but the clay is taken, pinch by pinch, each morsel being pressed into place as the work goes on. This plan is somewhat more plastic in effect and is well adapted to free-hand work; the resulting pottery, however, is generally thicker and heavier.
The craft of building is not mastered until the lines of a drawing can be successfully followed. The clay is apt to choose its own way and the result will be very different from what the potter intended. The design should be carefully worked out on paper, full size if possible, and the clay form should be compared with the drawing as the building goes on. A profile may be cut in cardboard and this, applied to the clay from time to time, will verify the line, but all such mechanical aids should be used sparingly as the value of this work depends largely upon the sense of freedom and self-expression which belongs to it.
The thickness of the clay walls is a matter of great importance. A small piece should not be so thick as to feel clumsy and heavy, nor should a large piece be so thin as to lose the sense of strength and solidity.
It may be found on drying the ware, that cracks, especially in the bottom, are developed. The cause of this may be in the clay. A clay which is too plastic or too fine in the grain will surely crack. Such a clay may be opened or meagered by the addition of ground flint or fine grog. The cause may, on the other hand, be in the building. If the welding of the coils or pieces be imperfectly done, cracks are sure to result. If the bottom be too thick it will crack. A great strain is put upon the bottom in drying. The clay must be able to shrink and while the side walls are able to settle down on themselves, the bottom is pulled in every direction by the sides. The bottom should be made quite thin in the center and thicker toward the edges. This will help to avoid cracks. A bad crack cannot be successfully mended. It is best to break the piece and begin again. To burn it means the loss of the clay but the clay will be saved if the damaged work be withheld from the kiln. A small crack on the edge is also hopeless. A crack showing on the edge of a piece is a bad fault. A small crack in the bottom may be mended by dampening the place carefully and pressing in a little stiff clay.