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| CHAPTER 2 The Making of Plaster Molds | ||
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THE SUCCESSFUL USE OF PLASTER is such an important part in the making of color cement tiles and pottery that as a preliminary step or auxiliary to the cement craft it should be well accomplished by the student before using the cement. It is not at all difficult and for those who have not used plaster, there awaits an interesting medium for all forms of plastic applications or adaptations. Our concern with it will be in the making of successful molds for the producing or reproducing of our cement tiles and pottery, but a whole book could be written upon the making of plaster objects. The uses of plaster form a large industry and many art objects are produced in plaster for many forms of applied art.
PLASTER IS SENSITIVE to moisture, and should be kept in a dry place. If plaster does not set within a short time it probably is old and even if it does set in time it will have a tendency to pulverize. It is always safer to purchase an entire sack than to purchase a small lot from the hardware dealer, grocer, or druggist, for the chances are that his plaster has been exposed in a bin so long that its strength has vanished. This is mentioned because instances have been known where trouble in cast making was traced to just such conditions.
ON RECEIVING THE SACKS OF PLASTER AND CEMENT the tendency will be to let contents remain in the sacks. It will be found much more convenient and economical to empty the sacks into a small barrel or box to which a cover has been made. A tin tray under the box or barrel will catch all waste that may drop around the edge, preventing the material from being tracked over the floor. A nail or hook on the side of the barrel for holding the ladle or spoon used for taking out the plaster will enable you to find it when you need it.
THERE ARE VARIOUS GRADES OF PLASTER, but the best for this purpose is molding plaster. The plaster should always be kept in a good dry location.