For controlling surface oxidation on your workpiece and to speed the flow of solder. Pour a small amount of water (distilled water is ideal) into the unglazed Ceramic Borax Dish and rub the bottom of the dish with the Borax Cone to form a paste. Using a small brush, apply the borax to the joint where solder is being applied. The dish will tend to soak up the water, but this tendency will diminish considerably over time. A very economical way to produce soldering flux. The dish has an inside diameter of 4” (103 mm).