Spraying Techniques of Water Based Paint Spray Gun

There are many construction methods of water-based paint, such as roll coating, spraying, brush coating and so on. Among them, spraying method is one of the most important methods of water-based paint construction. Thin and uniform film can be obtained by painting the surface of objects with spraying method. For objects with different shapes, small holes, gaps and uneven places, evenly distributed film can be obtained by spraying method. Moreover, for large-area things need painting, spraying is faster and more effective than brushing.

Next, let's talk about the skills of spraying water-based paint with paint spray gun:

1. Use clean water to adjust the paint to the appropriate viscosity of the high quality spray gun and measure it with a viscometer. The appropriate viscosity is generally 20-30 seconds.

If there is no viscometer at the moment, visual inspection method can be used: stir the paint evenly with a rod (iron rod or wood rod) and lift it to a height of 20cm to stop for observation. If the paint solution is continuously wired in a short time (a few seconds), it will be too thick; If the line breaks as soon as it leaves the upper edge of the barrel, it will be too thin; When stopping at a height of 20cm, the paint liquid will form a straight line, and the flow will be cut off instantly and become dripping. This viscosity is more appropriate.

2. The air pressure of the paint spray gun should preferably be controlled at 0.3-0.4 MPa (3-4 kgf / ㎠). If the pressure is too low, the paint liquid atomization will be poor, and pitting will be formed on the surface; If the pressure is too high, it will be easy to flow and hang, and the paint mist is too large, which not only wastes materials, but also affects the health of the operator.

3. The distance between the spray gun nozzle set and the object surface is generally 300-400mm. If it is too close, it will be easy to hang; If the paint mist is too far away, it will be uneven, prone to pitting, and the nozzle will be far from the object surface, so the paint mist will fly away on the way, resulting in waste.

The distance of spraying shall be properly adjusted according to the type of coating, viscosity and air pressure. The spraying distance of slow drying paint can be farther, and the spraying distance of fast drying paint can be closer; When the viscosity is thick, it can be closer, and when the viscosity is thin, it can be farther; When the air pressure is high, the distance can be farther, and when the pressure is small, it can be closer; The so-called closer and farther means a small range of adjustment between 10mm and 50mm. If it exceeds this range, it is difficult to obtain an ideal paint film.

4. The water based spray gun can move up and down, left and right. It is best to operate evenly at the speed of 10-12m / min. the nozzle shall be straight to the surface of the object for spraying, and oblique spraying shall be minimized. When spraying on both ends of the object surface, the hand holding the trigger of the spray gun should be loosened quickly to reduce the paint mist, because both ends of the object surface often need to be sprayed more than twice, which is the place most likely to cause sagging.

5. When spraying with paint spray gun, the next layer shall be pressed against 1 /3 or 1/4 of the previous one, so as not to miss spraying. When spraying quick-drying paint with water-based paint spray gun, it needs to be sprayed in sequence at one time, and the effect of supplementary spraying is not ideal.