Ruby Fluid® soldering and tinning paste flux 1.69 oz (47.91 g). Plumbers, workers in brass, copper, tin, steel and stained glass will achieve great results with this easy-to-use product. Produce strong, neat and durable joints. Ruby Fluid® allows solder to flow in a thin film. Adheres quickly and stays where it is applied. Also available in liquid (Forney 60301). Bulk version is Forney 38125.