As soon as the plaster has become warm the whole may be turned over and the templates and end plates removed. The four half spheres of clay will be found embedded in the face of the plaster and these, being removed, will leave four hemispherical depressions. The vase can now be gently detached from its bed and the first half of the mold is completed. A little dressing will be necessary. All overhanging edges and rough places should be finished off and the hollow natches smoothed with a piece of muslin on the end of a finger.
The second half is simple. Replace the vase in the half mold, set the foot piece in its place, replace the end plates with the diameter on the line as before but with the semi-circular edges upward, and set two or three clay natches on the bottom one. Size, bind up, pour and scrape off as before, thus completing the two halves of the mold in cylindrical form. It only now remains to make the bottom for, at present, the mold is open at both ends.
The two halves with the vase inside are bound very tightly together with twine and set on the table bottom upwards. The clay natches in the bottom are taken out and the hollows smoothed. The foot piece is taken out and the rough places dressed. The bottom end of the vase is now visible and this, together with the end of the mold, is sized. A strip of stout paper is bound around the mold, projecting about an inch above the end and plaster is poured to fill it. When this is set the paper is peeled off and the edges of the mold are dressed smooth. The bottom may now be detached by inserting a thin knife at the junction, the mold opened and the form taken out. The mold is now in three parts which may be put together at will and used for casting the vase in clay.
The mold described in the previous chapter is called, technically, a "block mold" and is not, as a rule, used for making the clay ware. The reason for this is that molds will wear out more or less rapidly and to repeat the process of making new ones from the original form would be tedious and expensive.
From the block mold a reverse is made, called a "case," and from this, in turn, working molds are made in any required number. While it is possible to use the block mold as a working mold, and, if only a few pieces are required this is quite sufficient, yet, as it is often necessary to have a number of molds, the student should understand how to make a case.