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life of that mold can be increased by a protective coating. This is given in the ordinary shellac, several coats of same are painted over the molding surface of the mold, after baking, allowing each one to dry before applying the next, this if properly applied makes a very smooth finish and also increases the life of the mold.

As is often demanded, the work should have a rough cast finish or the effect of tool dressed stone and in such event the smooth surface of the shellac must be roughened; this is accomplished by applying three coats, having the first one heavy and over same while yet fresh or sticky, sprinkle sand using care to have it evenly distributed and just to cover the surface; with the second coat you can remedy any places where the sand in first coat is not perfect, or to your liking, and with the third coat of shellac make a coating over all that is impervious to water and so capable of making a large number of casts, each with the true effect of tool dressed stone. Thin glue may be employed instead of the shellac with success, if it is more convenient.

CHAPTER IV

MAKING SAND MOLDS FROM WOOD AND METAL PATTERNS

THE method of making the mold must depend on the shape and condition of the pattern; if from a wood baluster, as shown in Fig. 2, the pattern may be divided in the center and the mold made to part along this division line. Where the pattern is to be simply a face plate as with a bas-relief design, but one section of the flask is required, and it is a simple matter to make the mold; in event the pattern cannot be divided there are several ways of securing the desired results, as will be explained in the following chapters.

The manner of making a sand mold from a pattern in two sections is illustrated in Fig. 2, which also applies to the making of bas-relief designs as well. The flask is built in two sec

tions so that it will be several inches larger each way than the pattern, and a cover or board slightly larger than the flask is laid upon the molding table; upon this the pattern is laid in the center, or in event of a sectional pattern one-half of same is placed on this board as shown at (c) in Fig. 2. The pattern is covered with fine dry sand, lightly sifted over same; this is in addition to the coating placed on pattern to prevent sticking; the molding sand or mixture of clay and sand is now placed in the box or flask in the same manner as filling a mold with concrete, using care not to disturb the position in which the pattern lays; the sand mixture is now rammed down tightly all over the surface and more sand added and tamped until it is solid, and the tamper will not make any decided impression on the surface of the sand; the top is then leveled off with a straightedged piece of board, and it is then ready to be reversed or turned over.

It is difficult to direct exactly how much the mold must be tamped, to enable it to lift without the sand falling out; the worker can easily

learn this with a few attempts, as the mold that is too loosely tamped will not lift without injury; there is little danger from over-tamping for this work, which is a decided difference from the sand molds of the metal worker, who must guard against tamping too tightly as much as against not tamping the mold enough.

The rods of 1/4" iron laid into the sand, across from one side of the flask to the other, as shown in illustration, are placed at the same time the sand is placed and the material packed tightly around same; these are a great aid in holding the sand into the flask when being lifted, and for the beginner or less experienced worker are invaluable, for they save many molds from breaking in the necessary handling. The rods must not touch the pattern and there should be at least 11⁄2" of sand between the pattern and the nearest rod; by having the flask large enough this can be arranged and the rods placed so that they will be even, between the top of pattern and the top edge of flask; where they will do the most service.

The tamper shown at (b) is easily made from

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