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Image ID: 302
Title:Fire clay tubes in the “muffle” kiln used for firing paint onto glass
Source:Raymond and Mildred Pitcairn Archives, Bryn Athyn, PA
Medium:35mm slide
Description: The details on a stained glass window (such as faces) were painted directly onto the glass and then fired in a special kiln. The painted glass was put into a kiln and fired at high temperatures until the paint bonded chemically with the glass: “The old factory building was still standing and from time to time I fired some glass for the windows for Mr. Hyatt in the old Denver kiln [Denver Fire Clay Company “Keramic Pottery Kiln no. 103”]” (Gunther, Ariel C. Opportunity, Challenge and Privilege. Bryn Athyn, 1973, p. 124). This is called a muffle, because we have to be very careful that the flame does not come in contact with the glass itself. If the flame were to come into contact with it, the oil which is used to paint those lines would fry up, and instead of having a solid line you would have a perforated line. And here you can see the kiln, with these tubes made of fire clay, through which the flame itself passes, and only the heat, is transferred to the glass itself” (Gunther, Ariel. Transcript of Bryn Athyn glassmaking lecture. Raymond and Mildred Pitcairn Archives, Bryn Athyn, Pennsylvania).