PRESSED or front brick are produced by a combination of the hand-made and the machine processes. The finishing of brick of this class is sometimes done in a press run by steam-power. The usual way is to mould the brick by hand and make them slightly larger than the size of the press-box in which they are to be finished.
The moulding, drying, and pressing of front brick are con ducted entirely under shelter ; the hand-press gang is composed of three members : the moulder, who also does the pressing ; the temperer, who also does the wheeling of the clay ; and the off-bearer, who also rubs the finished brick with very fine moulding sand.
A day's work for the press-gang is to temper the clay, mould, press, and finish one thousand one hundred and sixty seven brick. Pressed brick are seldom hacked on edge in the sheds, but are laid flatwise, each pile being a separate one, and a space of about three inches is left around each hack ; they hold shape better in this manner of drying than if hacked on edge, and after they have been pressed they are hacked differ ently, as will be explained.
For the information of brick-makers in distant places, where pressed brick have not been made, we elaborate further upon the general plan of making them by hand.
It is important that the clay should be well tempered, the clay-tempering-wheel producing the best. The brick should be moulded free from flaws or sand-cracks, and the mould, when in use, should be kept well cleaned. Those in general use in Philadelphia are known as the " single cast-iron moulds." The moulding sand is an important item in making pressed brick, as the color and smoothness of the brick depend on it. A sieve having about sixty meshes to the lineal inch is used for preparing the sand for moulding the brick. The brick are placed flat on the floor, and when pretty dry, a light sieving of sand is put over the faces. They are then turned over that they may dry more regularly. Sheds built expressly for the purpose are also used for pressed brick. The roof is made to open so as to admit wind and sun when required. Where the
brick dry too fast, a piece of damp carpet can be laid over them and sprinkled occasionally with water. When the brick are in a proper state for pressing—say, when they can be handled without finger-marks—the press is taken to the brick by placing the press on boards, the brick are carefully put into the mould, great care being exercised that they are not marked in dropping them in. There must be no finger-marks on them, and all " crumbs" must be wiped off the face of the mould ; also off the lid. After the brick are pressed they are generally laid flat, five or six high, and when partly dry they are slightly rubbed with the hand and piled pigeon-hole shape, which al lows further drying. In some cases they are piled in squares, edgewise, five or six high. When dry enough, they are placed on barrows, with strips of wood or soft blankets between each course, and taken to the shed to remain until required for burning. It is highly important that the mould lid and plate of the press shall be kept clean when in use. Occasionally raise the plunger plate, and wipe off any dirt that may have ac cumulated on it, and apply a slight oiling to all the parts. When the day's work of pressing is ended, make it a fixed rule that the presser shall take out the plunger, clean the mould lid and plate, oil the surfaces and replace. Occasionally, while working, the presser should clean the plunger and keep it al ways well oiled, as should be all the wearing parts of the press.
The pressed brick are usually set eight courses high in the kilns, but we have seen them carried ten or twelve courses in height in the city of Philadelphia. The top course does not usually extend closer than the fourth course from the top. They are also set differently from the way in which common brick are placed, the desire being to preserve the faces which are to be exposed in the wall of a building. There is not the same amount of crossing or "checkering" of this class of brick as in the common stock.