① The wrong diluent was used. The use of volatile paint thinner in enamel will promote the uplift of inner paint layer and eventually lead to the uplift of top paint layer.
② Incompatible raw materials were used. The newly sprayed paint layer reacts chemically with the original paint layer, or the defects of the original paint layer are not handled well, and the paint layer is separated, resulting in the uplift of the top paint layer.
(3) the bottom cleaning is not complete, such as the bottom surface grease or wax is not completely removed, repainted paint cannot be attached due to interlayer effect.
(4) The interval of secondary spraying is too short, and the primer is not given enough drying time, which causes the solvent on the surface of wet paint to corrode the primer or topcoat and soften it.