lead is another type of came used for glasswork projects. Lead The traditional method of creating "camework glass" uses lead came, which ages into a dark blue-gray patina. In comparison to other came metal strips, like brass, copper and zinc, lead is softer and more flexible, making it easier to cut and bend. It's also inexpensive and durable. A downside is that the finished projects may be prone to sagging due to lead's softness. This can be mitigated somewhat by stretching the lead to make it more rigid before it is used. Special precautions should be taken when working with this metal came to avoid lead contamination. The lead came windows of the medieval churches are sturdier than those of the 19th century and much of the 20th century. The composition of lead came changed over time, at first by removing other metals to make a "pure lead" and then again during war years when lead was needed for ammunition. Since the 1970s a new form of lead, restoration lead, was developed based upon medieval lead's metal composition. Restoration lead is stronger than lead came of the prior 100 years or so. Water tightness is achieved by brushing cement under the flanges of the leads to both faces prior to installation or by applying putty afterwards. Typically the cement consisted of linseed oil, whiting, lamp black and white spirit. Zinc Zinc makes a lightweight, strong and rigid came, which lends itself to glasswork projects that don't have many curved lines, are large, or have a number of straight lines that require greater support than lead would afford. Zinc accepts finishes, such as black and copper. Because of its strength, zinc is often used for border cames, which are U-channel cames for the outside edges. Frank Lloyd Wright used zinc came for his stained glass windows. Beveled glass work is generally done in zinc came, primarily because of its ability to manage the weight of heavy plate glass; whereas beveled glass works made of lead came are much more likely to buckle or sag over time. Copper foil Copper foil is an easy, versatile alternative to came and is particularly useful for small projects. Using copper foil, the edges of the glass pieces are wrapped with adhesive copper tape and soldered together along the adjacent copper strips. A patent for the method of "Joining Glass Mosaics" was issued to Sanford Bray