Kiln builder, potter and furnace crew slang for dense refractory brick, usually fireclay or high-alumina, heavy at roughly 3.5 kg or more per 9-inch straight and strong enough to take load, abrasion and flame. It conducts heat far better than insulating firebrick, so it goes on hot faces, floors, burner zones and anywhere that takes a beating, with soft brick behind it.
Hard brick on the floor and around the burner ports, soft brick everywhere else.
Also heard as
- dense brick
- dense firebrick
Related terms
Soft brick
Shop and kiln builder name for insulating firebrick, light enough to carve with a hand saw.
Fireclay
Alumina-silica clay refractory, the classic firebrick, graded from low duty to super duty.
IFB
Insulating firebrick: light, porous brick rated by the maximum temperature it can face, such as group 23 or 26.
Thermal conductivity
How readily a material conducts heat, the number used to size lining layers and predict shell temperature.