Skilful operation of Hoffman kiln
Skilful operation of Hoffman kiln
It is clear that a Hoffmann kiln required a skilful and careful operation. If the temperaturewas too high, the bricks would come out
misshapen. If the temperature was too low, the bricks would be weak and porous. If the bricks were heated up or cooled down too fast,
this would result in cracked, warped or twisted goods. The man in charge of the kiln ascertained the completion of the burning by means
of trials,shrinkage measurements and Seger cones (picture on the right). In a well operated Hoffmann kiln, on average only 3 percent of
bricks were spoiled, but with inferior management this could be 50 percent.