Defeitos e danos na pintura

501-36-14 Paint - General Information 501-36-14 DESCRIPTION AND OPERATION Paintwork Defects and Damage Diagnosis and Damage Assessment Paint concerns, regardless of their causes, are part of the everyday work in the paint shop. Correct damage assessment and determination of the cause are preconditions for a professional resolution of a paint concern. Paint concerns can still occur through a variety of causes, despite improved paint materials and new spray methods. NOTE: A first appraisal of the paint damage should be done before cleaning. External factors such as rust, droppings, incorrect or insufficient paint care can then be more easily detected. Diagnosis is best done in daylight but not in direct sunlight. Exact evaluation can also be done under artificial light from special luminescent lamps. Paint damage guide The most important paint damage concerns which make a paint repair necessary are: ‡ Damage from biological paint contamination such as bird or insect droppings, tree resin and aphids. ‡ Chemical paint damage caused by industrial contaminants such as smoke, fuel, acids, oils. ‡ Mechanical damage caused by stone impact during operation, scratches in the car wash and parking. ‡ Damage caused by faults in treatment. Application defects such as paint runs or orange peel. ‡ Dirt inclusions in the paint layer, e.g. caused by dust in top coat or textile lint. ‡ Damage due to corrosion. Before repair of such paint concerns, exact diagnosis must be performed to determine the cause exactly. On the spot diagnoses using simple aids and processes are often enough. Diagnosis without disturbing the paint is done by: ‡ Optical inspection without visual aids, under suitable light conditions from a suitable angle and correct distance. ‡ Optical inspection with the help of a magnifying glass. ‡ pH paper. ‡ Measurement of the thickness using FE / NFE coating thickness meters for ferrous (FE) and non-ferrous metals and non-magnetic steel (NFE) - magnetic process on steel panels, eddy current process on non-metals. A test method where the traces of testing can be easily removed again is the finger nail test. With suitable experience the existing hardness of the paint can be determined. Test methods where the paint is partially destroyed are: ‡ Pencil hardness test. ‡ Adhesion test using adhesive tape. ‡ Lattice cut test process to check the strength of adhesion. Under certain circumstances these test methods are not enough for a certain diagnosis. In this case, paint diagnosis under laboratory conditions must be performed. Measuring and testing equipment for painted surfaces Coating thickness measuring devices Magnifying glass pH paper (together with water) Suitable photographic equipment with macro lens Shine measuring equipment Paint damage caused by environmental factors ‡ Bee droppings ‡ Bird droppings ‡ Insects ‡ Tree resin and sap ‡ Aphid secretions ‡ Tar spots ‡ Cement, plaster and slaked lime ‡ Rust film/deposits from industrial fallout ‡ Battery acid ‡ Brake fluid