Youlinsheng Group states that spraying is one of the most important methods for applying water-based paint. By using spraying to coat the surface of an object, a thin and uniform coating film can be obtained. For surfaces with various geometric shapes, small holes, gaps, and unevenness, the paint can be evenly distributed. For large surfaces, spraying is faster and more effective than brushing. Today, our editor will share with you some tips and key points for spraying and applying water-based paint.

 1. Use clean water to adjust the viscosity of the interior and exterior wall paint to a suitable level for spraying, as measured by a Tu 4 viscometer. The appropriate viscosity is generally between 20 and 30 seconds. If a viscometer is not available, a visual method can be used: use a stick (iron or wooden) to stir the paint evenly and lift it to a height of 20 centimeters and observe. If the paint does not break within a short period of time (a few seconds), it is too thick; if it breaks immediately upon leaving the top edge of the bucket, it is too thin. The ideal viscosity is such that when the paint is just lifted to a height of 20 centimeters and stopped, it forms a straight line and instantly breaks into drops falling downwards.

2. The air pressure should ideally be controlled between 0.3-0.4 MPa (3-4 kgf/cm²). If the pressure is too low, the paint will not atomize properly, resulting in pitting on the surface. If the pressure is too high, the paint will sag and the paint mist will be excessive, which not only wastes materials but also affects the operator's health. 3. The spraying sequence is: tackle the difficult areas first, then the easy ones; start from the inside and work outwards; work from high to low areas; and start with small areas before moving to larger ones. This way, the paint mist from later spraying will not splash onto the already sprayed paint film, damaging it.

 The distance between the nozzle and the surface is generally recommended to be 300-400mm. If it is too close, sagging may occur; if it is too far, the paint mist will be uneven, prone to pitting, and the paint mist may scatter en route, resulting in waste. The specific distance should be adjusted according to the type of paint for interior and exterior walls, viscosity, and air pressure. For slow-drying paint, the spraying distance can be longer; for fast-drying paint, the distance can be shorter. When the viscosity is high, the distance can be shorter; when the viscosity is low, the distance can be longer. When the air pressure is high, the distance can be longer; when the pressure is low, the distance can be shorter. The so-called "a little closer, a little farther" refers to adjustments within a small range of 10mm to 50mm. If it exceeds this range, it will be difficult to obtain an ideal paint film.

5. The spray gun can move up and down, left and right, operating uniformly at a speed of 10-12 meters per minute. The nozzle should be kept straight and perpendicular to the surface being sprayed, minimizing oblique spraying. When spraying onto the ends of the surface, the hand pulling the spray gun trigger should quickly release it to reduce paint mist, as the ends of the surface often receive more than two coats of paint, making them the most prone to sagging.

6. When spraying, the next pass should overlap the previous one by 1/3 or 1/4 to avoid missing areas. When spraying quick-drying paint, it is necessary to complete the spraying in one go and in order, as re-spraying may not yield satisfactory results.

When spraying in an open outdoor area, pay attention to the wind direction (it is not advisable to work during strong winds). The operator should stand downwind to prevent paint mist from being blown onto the already sprayed paint film, causing an unsightly granular surface.

  Historically, the Youlin biological physical model has been a primary method for predicting VOC emissions in studying the impact of paint films on environmental pollution. Mainstream physical models include the boundary layer evaporation model (VB model), VBX model, the semi-analytical two-layer model describing evaporation and diffusion, as well as some more complex mathematical models. Most models focus solely on VOC emissions without considering changes in paint film thickness during the process. While such simulation processes can accurately predict TVOC, they may exhibit significant deviations in predicting certain specific types of VOCs. Given the varying potential threats posed by different VOCs to human health, a correct understanding of the emission mechanism can help correct these deviations. In widely used interior latex paints, water, as a solvent, greatly affects the state of the paint film and VOC residuals during evaporation. Therefore, the drying process of latex paint should also take into account water evaporation. On the other hand, after drying, the VOCs in the latex paint will act as slow emitters, causing continuous pollution to the indoor environment. Studying its emission mechanism can help reduce VOC residuals and their impact on the environment. Anhui interior and exterior wall paint manufacturers