Slang for insulating firebrick, used by kiln builders, potters, heat treaters and furnace crews. Soft brick is so light and porous that it can be cut with a hand saw and gouged with a fingernail, and it saves fuel by storing and conducting little heat. It is easily damaged by impact, abrasion and slag, so it lines the inside of clean kilns or sits behind hard brick in industrial furnaces.
Kiln walls are soft brick so don't lean on them, and keep glaze drips off the floor.
Also heard as
- soft firebrick
- insulating brick
Related terms
IFB
Insulating firebrick: light, porous brick rated by the maximum temperature it can face, such as group 23 or 26.
Hard brick
Shop name for dense firebrick, as opposed to lightweight insulating soft brick.
Thermal conductivity
How readily a material conducts heat, the number used to size lining layers and predict shell temperature.