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Owners of older homes appreciate the beauty of stained glass. In some cases, the stained glass windows may have been the emotional “reason” that prompted you to buy your house. But as with so many other aspects of old house ownership, stained glass needs maintenance and care. Below are some suggestions on how to care for your windows — and how to recognize when to call in an expert.
A stained glass panel is constructed of 1) individually cut pieces of clear or colored glass, or bevels; 2) held together by a matrix of lead came or copper foil. Lead came dates to mediaeval times and is the traditional method of assembling leaded glass panels. Zinc came is associated with the prairie designs of Frank Lloyd Wright and his contemporaries. Copper foiling is the method introduced by Louis Comfort Tiffany, and is the preferred method for constructing intricately designed art glass panels and lampshades. An additional step in the construction of leaded glass panels is the application of cement to fill the space between the glass and the inside surface of the lead or zinc came. Cement is applied to the front and back of the panel to weatherproof and add strength to the panel. Large panels also should be braced with saddle bars or reinforcement bars.
Inspect your windows for age and buckling. To assess the condition of the lead or zinc cames, look for telltale signs of metal fatigue and corrosion. Old lead is still functional if the exposed face of the metal (the flanges) can be lifted and flattened without cracking. Lead covered in a fine white powder has oxidized and has reached the end of its useful life. Zinc covered with small white spots is worn out, too. Examine the metal for hairline cracks near the joints, particularly around the border of the panel. These indicate metal fatigue.
