Liquid flame spraying for glass coloring

The liquid flame spraying process has been developed to uniformly color hot glass objects. A solution consisting of a metal nitrate dissolved in alcoh ol or water is fed to an oxyfuel torch and atomized in the flame. The liqui d evaporates from the droplet, and subsequent reactions produce metals or m etallic oxides that impact the hot glass surface. Flame spraying of Co, Cu, and Ag solutions onto soda-lime silica glass at 900 to 1000 degrees C have produced blue, blue-green, and yellow colors. Typical spraying times are 5 to 20 s. Other colors have been produced by using a combination of transit ion metal ions, This method has found application in studio production and in volume manufacturing of glassware.