Assessment of Selected Properties of Varnish Coating of Motor Vehicles

The technology and methods of testing the properties of varnish coatings used in motor vehicles are constantly and successfully developed. However, in the case of automotive varnish renovation coatings used in the repair of car bodies, the problem of fitting the quality of these coatings to the quality and current condition of the coating applied to undamaged vehicle components is not definitely solved. The main goal of the research was to determine the thickness and gloss distribution of the varnish coatings. The thickness and gloss of the varnish coating on the entire body of the vehicle were measured. Classical methods of assessing these properties were used. Defects in the renovation coating were also simulated, to show their negative impact on the varnish quality. The performed tests allowed for development of a procedure and algorithm for evaluation of the quality of the car’s renovation coating after the repair of the car body. The proposed procedure, expressed with the presented algorithm, allows to fit the obtained renovation coating to the quality and condition of the coating manufactured in factory on the car body in the range of its thickness up to 270 µm and gloss in the range of 5–90 GU. The developed procedure for the assessment of renovation coatings can be used in workshops that repair vehicle bodies. This will allow to improve the quality of renovation coatings and bring their properties, such as thickness or gloss, closer to those applied to the vehicle’s body at the factory.