One of the most widely used was an open clamp, in which bricks were placed on a fire beneath a layer of dirt and used bricks. Prior to the mid-1800s, people made bricks in small batches, relying on relatively inefficient firing methods. of fresh mortar on each course of face brick into place, leaving a 1/4-in. Generally, a traditional brick made of natural fire clay is nearly as good as a brick, but when more acid resistance is required, a further amount of silica is added to the fire clay, which increases its composition, up to 97%. Francine. I think you can make a fire brick from plaster of Paris and sand then place in a mould and allow to set. Nowadays they are called heavy and dense Firebricks but old masters still call them fire clay bricks just because they are made of simple fireclay (which actually is the most ordinary mud. gap between the firebrick and the face brick. )Fire clay can be easily located out in the nature but it must containing the right refractory properties, suitable content ratio of silica and alumina. Check the level of each course and tap down the bricks … Need to know if these bricks … November 10, 2019. Working on one-third of this easy fire pit at a time, lay 3/8 in. Acid bricks are burnt at high temperatures for a very long time. 2. Some shops call these bricks fireplace bricks. Reply. But work fast because it can set fast. A Brick with Many Faces Fire brick is a generic term that encompasses any brick … Fire brick, ceramic fiber and castable refractories are the three forms of refractories used in kilns, but fire brick is the most significant. Basic Fire Bricks: As the fire died down over the course of several weeks, the bricks … Very interesting. Like Like.