FACTORY FIRING AND GLAZING
The pipes were packed in round stoneware crocks or saggers made from fireclay, and the saggers were stacked alternately around the kiln. The saggers were some eight inches high and 16 to 18 inches in diameter ([Plate 7]). There was an opening in the top of the kiln through which, in glazing, salt was put when the pipes were hot. They were fired some 24 or 48 hours (Miss Thornton’s statement).
Mrs. Maddox said: “As a child I used to go with a colored man who worked with us and also for the factory, and watch him throw salt down a hole in the top of the kiln on the pipes to make a glaze.”
At a high temperature the salt vaporized and combined with the silica in the body of the clay to form a glassy or ‘silicate glaze’. The kiln was fired 32 to 36 hours before maximum temperature was reached; it was cooled the same period to prevent crazing (minute cracking) of the glaze (Blair, 1965:15). This description of glazing refers to stoneware in the mid-nineteenth century potteries near Akron, Ohio. However since the Pamplin kiln was the same sort of “walk-in” kiln, the detail would fit, and it is substantiated by Miss Thornton’s statement of firing time.
From the scarcity of glazed pipes among the many that we examined, we conclude that the majority were finished without glazing.