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Preface: In the actual process of corrosion prevention management, attention is sometimes overlooked regarding \"preparations before painting and precautions during painting,\" or insufficient preparation for certain steps, which leads to problems with the quality of the work. So it would be good if the two issues introduced this time are helpful to us managers. I. Preparations before painting 1. Before painting, it is necessary to check whether all types, models, and specifications of paint meet the requirements specified in the construction technical conditions. Paint that is of substandard quality or has deteriorated cannot be used. 2. Before painting, it is necessary to understand the basic composition and properties of the paint as well as the application methods; appropriate painting tools should be selected based on the specific requirements of each type of paint. 3. Due to the different densities of various components in paint, varying degrees of sedimentation generally occur in paint after storage. Therefore, the paint must be stirred until it is completely uniform before painting. If paint flakes or particles are found, they should be filtered using an 80–120 mesh sieve. 4. Epoxy primers, epoxy asphalt paints, epoxy coatings, polyurethane topcoats, etc., are all coatings that come in two separate components: Component A and Component B. It must be mixed evenly according to the specified weight ratio before use; if the mixing ratio is incorrect, it will affect the drying properties and rust resistance. Epoxy paints and polyurethane paints belong to the cross-linked curing type; after mixing the component A and component B, they need to be allowed to mature for 30 minutes before they can be used. At 20°C, they will gradually gel over a period of 12–20 hours until they can no longer be used, or until the valid usage period specified in the product instructions is reached. Therefore, it should be calculated based on the painting area before mixing. 5. Ordinary paints are already adjusted to a viscosity suitable for application at the time of manufacture, so there is no need to dilute them. However, in conditions of excessively high or low temperatures, an appropriate amount of thinner can also be added to achieve the desired coating viscosity; yet the amount of thinner used should generally not exceed 5% of the weight of the paint itself. II. Precautions for Painting 1. Brushing: When applying paint with a brush, the brushing direction should be from top to bottom first, followed by left to right; the brush should not be dipped in too much paint to avoid dripping. When applying a heavy-duty anti-corrosion coating, the brush should not be held too far away to prevent the paint film from becoming too thin. Special attention should be paid to areas with a rough surface, edges, corners, and protrusions; it is best to apply a preliminary coat first. 2. Roll coating: When using a roller for painting, the paint on the roller should be distributed evenly. During painting, the rolling speed must be kept at a constant level and should not be too fast. Be careful not to apply too much force when pressing the roller. Special care should be taken with protruding parts such as welds and notches; it is best to apply a pre-coating first. 3. High-pressure airless spraying: This is the fastest coating method, and it allows for the creation of very thick paint coats. Therefore, to achieve the specified film thickness, it is best to use airless spraying as the application method. During actual painting, a vertical and horizontal spraying method should be used, applying paint first from top to bottom and then from left to right, or first from left to right and then from top to bottom. Using airless spraying requires higher skill; the spray gun should be kept at a horizontal distance from the surface to be painted, and care must be taken to avoid swinging the gun over long distances or in arcs during operation. 4. Control of paint film thickness: The thickness of each paint film listed in these instructions refers to the thickness achieved through airless high-pressure spraying. To enable heavy-duty anti-corrosion coatings to perform at their best, an adequate paint film thickness is extremely important. Therefore, the thickness of the paint film must be strictly controlled. During construction, painting should be carried out according to the required amount; a paint film thickness gauge should be used frequently to measure the thickness of the wet paint film, in order to control the thickness of the dry paint film and ensure uniform coating thickness. Determine the density and distribution of thickness measurement points based on the size of the object to be coated, and then measure the thickness of the dry paint film. Areas where the paint film thickness does not meet the requirements must be repainted. 5. The intervals between different types of coatings vary; during application, each type of coating should be applied according to its own requirements. It is particularly important to note that for products such as epoxy asphalt thick-coat anti-rust paint and epoxy topcoats, the interval between applications must not exceed the maximum interval specified in the instructions; otherwise, it will affect the adhesion between the different layers of the paint film, leading to its peeling off.