Sand inclusion in paint film
Any dust or other contamination from blasting and mechanical preparation methods will need to be removed prior to painting. If not removed, slag and dust will blend with the freshly applied coating. Pay special attention to abrasives and dust from scaffolding, which can deposit on freshly painted surfaces. These contaminants can be removed manually or mechanically. Blow dry thoroughly with compressed air before painting. Pay special attention to the joints of scaffolding, which are prone to dust accumulation and are not easy to remove.
dry spray
It means that the liquid paint is semi-dry before reaching the surface of the object to be coated, but there is still a certain amount of humidity that can just adhere to the surface to form a film, but it cannot form a continuous and effective paint film. Because the dry spray particles will lose some solvent when they are sprayed on the material to be coated, then semi-dry paint dust will be formed, with poor or even no adhesion.
The reason for dry spraying is poor construction technology: the distance when spraying paint is too far; the gun is arc-shaped or inclined; the temperature is too high; the pressure of the paint pump is too high;
When spraying the topcoat on the freeboard of the ship, due to the strong wind when working at high altitudes, it is easy to cause dry spraying on the waterline and straight bottom.
Existing overspray on the surface shall be removed. Dry and stuck particles can be swept or shoveled away. If overspray particles are allowed to settle on the surface, the next coat of paint will form a discontinuous film, pin corrosion will occur, or there will be poor adhesion between coats.
