Tin Side Detector
Short Wave U.V. Light
Window glass has a front and a back side. The back side was in contact with molten tin during the manufacturing process. Enamels placed on the back side will have a yellow shift in color, blues will turn green, red will turn brownish orange. Although this can be used to create a second palette of colors, it is best to know which side of the glass you are working on. When the glass is viewed under a Shortwave U.V. Light, the ‘tin’ side appears to have a white haze on it, the front side is clear.
In the example to the right, two strips of clear are placed on the UV light, one with the tin side up and one with the tine side down. When viewed in a dark room, the strip with the tin side down, shows a slight white cloudiness while the strip with the tine side up is still clear. This effect is subtle, so requires a little practice to get good at reading the glass.
Requires 4 AA Batteries.