called apparent viscosity. This is the feature of many solidified colloids for becoming predominately liquid under the influence of mechanical forces (sol-gel transition). Provided lacquers applied with thixotrpoic agents are in motion, i.e. being shaken or stirred or, as may apply, sprayed, they are relatively fluid (sol state), but if they are at rest they solidify immediately. A gel is formed. In order to prevent the polyester lacquer film from running off or tearing off on standing surfaces, thixotropic agents are added to the lacquer either before spraying or even at the manufacturer. Thixotropic lacquers are certainly easier to work with on standing surfaces and when working above head-height, but do not level very well on horizontal surfaces, which involves increased effort when sanding the lacquer