FIRE-BRICK MANUFACTURE See FIRE-CLAYS, under head of CLAY in Chapter II. The details of manufacture and the equipment of plants for the pro duction of fire-brick vary with circumstances and the kind and variety of brick to be made, which may range from the smallest nine-inch shape, weighing three pounds, to the largest glass house shapes, weighing 3,500 pounds or more.
The manufacture of fire-brick, from the mining of the crude clay to the delivery of the finished goods from the kiln, is a succession of processes simple enough in themselves, and easy enough to those who are thoroughly skilled in the trade, yet involving great care and incessant vigilance in order to insure continued success.
Both a practical and theoretical knowledge of the business is highly desirable, if not absolutely necessary, in the person who assumes the active management, be he proprietor or hired manager. By practical knowledge is not meant that he should have the physical ability to go and take a moulder's or presser's or setter's place and do a day's work. But a man in this posi tion should be so practical as to be able to tell at a glance whether a brick or piece of shape-work is made properly or not, and if not, what is the matter with it. He should be able to tell as soon as he feels of the tempered clay whether it is too soft for the work for which it is being used, whether the kiln men are setting the brick and shapes to the best advantage, whether the, firemen are firing a kiln right or only putting in the time, whether a kiln has heat enough or needs to go twelve hours longer. He should be able to tell when he comes into the works by the sound of the machinery whether it is running all right or not. These, and a hundred other things, to the "practical" manager should come as natural as life. If the works are of any extent, so that he has a foreman under him, he may not have to notice some of these things once a month, or longer, but he should possess the knowledge, and when least expected it will serve him in good stead. He may or may not be able to handle men to advantage ; if not, he will see to it that he gets a foreman who has the knack of doing so, for it is a gift all men do not possess. Theoretical knowledge means a
great deal more than might at first thought be supposed. If a man as manager or general superintendent is ambitious of at taining the highest results he needs to become acquainted with the following branches of science : Chemistry, geology, mining, mineralogy, metallurgy and mathematics. Chemistry will teach him the composition of clays, the specific influence for good or evil of one element upon another, the correct selection and mixing of clays to make fire-brick suited to different uses. Geology will teach him all that can be known of the formation and origin of clay beds, and also where to prospect for the clay he may be seeking, according to the different formations. Mining will teach him how the clay can be mined profitably, economically and without waste of clay territory. This depart ment, however, is often taken out of the hands of the manager of the works and given in charge of a competent mining engineer, especially where, as in many cases, the miners are at some distance from the works. Metallurgy teaches the dif ferent processes used for extracting metals from their ores and the mode of manufacture of the various metals, and thus shows the requirements, sometimes special and extraordinary, of fire brick for use in different processes, with the effect upon them in various positions and at different temperatures. Mathe matics is of great use to the manager in calculating the sizes and shrinkages of difficult shapes.
These subjects enter into the theoretical knowledge which a manager does well to have. Some are of less importance than others. Chemistry and metallurgy are almost invaluable, show ing as they do on the one hand the causes which tend to the destruction of the brick under diverse conditions, and on the other hand how to make brick that will present the greatest resistance to destruction, by a proper selection and mixing of clays. Such knowledge will save a man from many costly mistakes into which he may otherwise fall.