Putty or primer cracking
In the paint repair area, the putty-filled area or the primer layer cracks, resulting in cracking of the topcoat layer.
(1) Cause:
① The putty layer or the primer layer is too thick, and the drying time between each layer is insufficient, so that the surface of the putty layer or the primer layer is dry and the bottom layer is soft, resulting in cracking of the putty layer or the primer layer. Therefore, in the putty scraping or primer spraying, the method of multiple constructions in thin layers should be adopted, and sufficient drying time should be allowed according to the climatic conditions.
②The transition area between the putty or middle coat primer layer and the old paint layer, that is, insufficient treatment around the feather edge, resulting in the loose combination of the putty coating and cracking, 600 grit sandpaper should be used to avoid bringing the solvent into the The deep scraping layer of the lower layer.
③ The use of unsatisfactory thinners in the primer makes the primer layer not easy to dry or shrink excessively and crack.
(2) Correction method:
Sand the cracked area thoroughly, re-scrape putty and apply primer and topcoat, taking care to allow sufficient drying time between coats.
