The History Of Fire Bricks
(Contributed by John Cooksey)
The Manufacture of Refractories
First the term ‘refractories' must be explained. The use of
the word ‘firebrick' is preferable but this would not be technically
correct. If brick is taken as the shape and size of a normal
house brick, i.e. 9”x 4.5” x 3”, these would only represent
about 15% of all refractories made. The rest would be made
up of articles ranging in weight from a few kilos to several
The making of bricks has been an industry for over 5,000 years,
but the making of fireclay related articles only about 250
The way in which refractories and building bricks are made
have a few important differences, mainly the clay and the way
it is extracted. Black Country fireclay, with one exception,
was always mined, blasted out between and below the coal measures
normally between 90 and 400 feet, The exception was Doultons
opencast at Saltwells near Netherton where nearly a million
tons were opencast in 52 years. It is now a fine nature reserve..
Red brick clay for this area is called Etruria marl and that
was and still is extracted by the opencast method. Big holes
in the ground were always referred to as Marl Holes in the
Black Country . The area has just one marl Hole left; any other
works that require marl have it brought in. Blue bricks are
also made using Etruria marl, their hard solid blue colour
is achieved during their firing using a reducing atmosphere
cutting down on oxygen in the kiln.
Another big difference between refractory and red brick manufacture
is the amounts of clays or materials used in their making.
Building brick would require three at the most, the number
used making refractories could be a mixture of as much as 38.
This was the case at Harris & Pearson's yard at Silver
End Works, and this does not include the slip casting of large
heavy blocks for the container and float glass industries that
required additional clays and chemicals.
The ways in which bricks and blocks are made are many: hand
moulded with either slop moulding or semi stiff clay, pressed
singly or multi pressed, wirecut, slipcast, or compressed air