How to prevent the surface of paint construction from falling?

Sometimes the grass surface of the coating appears like water droplets, and some places on the surface there are sand-like bulges, what is going on? How can I prevent it?
paint construction common two phenomena: one is paint drop, one is paint film surface rough
The main reasons are:
1. the preparation of the paint is too thin, poor adhesion, part of the paint under the action of gravity to produce flow;
2. brushing or painting too thick, paint film too heavy fall, construction environment temperature is too low, paint film dry slowly;
3. There are too many heavy pigments in the paint, part of the paint drooping, the surface of the object is uneven, the paint film thickness is not uniform, the drying speed is different, the paint film is too thick part of the easy to fall;
4. the surface of the object has oil, water and other dirt and paint incompatible, affecting mucous knots, resulting in the paint film sagging.
what can be done to prevent paint falling?
first we have to select good quality coatings and dilutors with the right volatilization speed, and control their infiltration

. Secondly, the surface of the object should be treated smooth, smooth, remove surface oil, water and other dirt. The ambient temperature of the re-construction should meet the standard requirements of the coating type, such as varnish should be 20 to 27 degrees Celsius, and within 3 hours to complete the brushing. Paint again should be carried out according to the process procedure: first vertical, horizontal, oblique, and finally vertical to level the coating, so that the thickness of the coating film is uniform. Finally, when spraying the gun movement speed and distance from the object to control uniform, according to the prescribed process procedures, first vertical spray, ring spray, and then horizontal spray, so that the paint film forms a uniform, thick and consistent.
surface roughness of the coating film is reflected in the coating film, the surface is uneven, with sand grain-like bulge or small bubble-like. The main reasons are:
1. paint pigment too much or particles too thick, paint itself is not clean, mixed with debris, not screened to use;
2. when the ambient temperature of the paint is low, the bubbles in the paint are not completely dispersed and discharged;
3. The surface of the object is not cleaned, there are sand particles and other debris, mixed into the paint film when painting,
4. the use of the body (brushes, paint barrels, spray guns, etc.) unclean, there are residual debris into the paint,
5. construction environment cleaning and protection is not enough, the brush has dust, sand and other debris glued to the brush or fell on the film.
To prevent the surface of the paint film rough, we also have a few precautions:
first of all to choose a good quality paint material, before use must be too fine sieve, reconcile evenly, no bubbles after use. Next, pay attention to clean the surface of the object, keep it smooth, smooth, dry. Then reasonable arrangement of the construction order of each type of work, to ensure that the paint construction environment without debris, dust-free is very important. Finally, be careful not to reuse appliances that are filled with different models and different properties of lacquer materials, and remove their residues when needed before using them.
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