A device to aid the mold-er to obtain quickly and easily a "parting line" in the mold is called a match. It supports the pattern and consists of a false part of the flask on which the drag is rammed. The match is about 3 in. deep and is made of some material confined within a wooden box or part of a flask to which a bottom board is securely fastened, the pattern or patterns being partly embedded.
Many different compositions are used to make up the hard support for the pattern. Sand, mixed with linseed oil and baked after shaping, is a very good mixture. Sand mixed with litharge also gives a very hard match, as does plaster of Paris. While this latter composition is more brittle than the other mixtures, an addition of litharge will tend to toughen it.
Since the invention of the molding machine, the match is not so much used as formerly. The great advantage of the molding machine is its facility in the production of small castings in which the patterns are of metal, mounted, or "gated," as it is termed, on a runner. Several castings may be obtained in each mold with no more labor than is needed to obtain one casting if only a single pattern is used.
The making and preparation of the patterns for match-molding are usually the work of the metal pattern-maker. The first pattern is usually of wood and is called the master-pattern. From it the metal patterns are obtained.