We love this Stuff! - One of our favorite things to do- visit a manufacturing plant! Having a clear understanding of what it takes to make the materials we use sparks a further interest in how we could exploit that particular material. Our friends at Glen Gery Brick provided an excellent tour of their plant which is right in our back yard.
The oldest manufactured module of construction in the history of building.
It all starts with the raw material preparation. The manufacturing of brick begins with the gathering of surface clays and shales from the Pennsylvania quarry. The raw material is then prepared and crushed to a fine consistency. Water is added to provide the proper plasticity and materials, such as manganese, are added to change the body color.
Handmade, machine molded or extruded, each manufacturing method imparts a different look. In the handmade method, a soft mixture is forced through an extruder, cut into slugs and conveyed to work stations. The slugs are then individually picked up, rolled in sand and thrown into a pre-sanded wooden mold by a worker. Excess raw material is removed by a wire and endless belt. As the filled mold boxes continue on their journey, they are mechanically bumped on their ends to loosen the brick from the mold prior to dumping.
The setting and drying process is next in line. After the brick unit is formed, the units are hand or mechanically set onto kiln cars.
The next step is burning or firing the green brick. The green brick pass through the long length of the kiln on a continuous procession of cars moving on rails. The continuous tunnel kiln employs a combination of vertical and horizontal drafts. The preheating, burning and cooling is done in zones varying in temperatures. The type of firing influences the range of color. The color variations being the extremes of dark color nearest the fire or in the crown on the kiln and the light color at the bottom where the brick have the lowest temperature.