Heavy-duty anti-corrosion paint in the painting process, the common problems often occur in the quality of the project, such as the bottom of the coating, the foaming of some areas, etc. This is caused by the fact that the paint film will appear in a short time after the topcoat is applied. Automatic expansion, displacement, shrinkage, wrinkling, partial area bubbles, and even the underlying paint film loses adhesion, and the underlying coating is bitten off. The matching performance of the coating is not good, and the primer and topcoat are not matched. A coating containing a strong polar solvent is applied to the upper layer of the coating made of a less polar solvent. For example, if the rosin-containing resin is coated with a lacquer, the rosin-containing resin is coated with a lacquer; the anti-corrosive lacquer is coated with an alkyd paint; and the alkyd or varnish is coated with an oxidized rubber coating. Polyurethane coatings, etc. The penetration and swelling of the paint film by the strong solvent causes the undercoat film to bite. Apply the next coat when the coating is not dry. If the vinyl chloride varnish or varnish is not dry, apply a second coat. When applying a top coat or a down coat, use an excessively strong thinner to swell the primer.
The control measures are to prevent the anti-corrosive paint from drying out and to perform at the optimum coating interval, and the minimum coating interval must be reached. In the winter construction, the coating interval can be extended appropriately to ensure the smudge of the primer. For special varieties of coatings, the "wet-on-wet" coating process can be applied. When the first layer is not dried, a layer is applied to improve the adhesion of the coating. Paint in strict accordance with the paint instructions. Generally, similar anti-corrosive paints can be matched with each other. Different types of coatings are supported by the principle of hard and soft; for example, the primer is made of strong solvent paint, and the top coat is made of weakly soluble paint. It is not suitable to apply lacquer on the rosin resin film. If it is to be painted, it must be polished, brushed with a filter layer, dried and then cleaned with a clean rag to remove coarse particles. After sanding, repaint Large paint. For coatings that have the problem of "biting the bottom", they can no longer protect and decorate. The coating at the bottom position should be shoveled. Make up and improve the package. In the case where the primer is not dry, apply the top coat after the primer has dried out.
In order to prevent the bite, the first coat should be thinner, and the second coat should be applied after it is completely dried. It cannot be coated too thick at one time, so that the internal solvent cannot be volatilized and the drying time is prolonged. The thinner used in the coating of anti-corrosive paint should not exceed 5% of the total coating amount. The variety should be fixed during the coating process. The weak polar diluent should not be used in the bottom layer. The upper coating is made of strong polar solvent such as acetone and ester. Classes and high boiling aromatic solvents and the like.
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