What Are the Usage Methods and Precautions of Painting Spray Gun?

Painting construction plays a decisive role in the final surface effect, anti-corrosion effect, decoration effect and the quality of the paint itself.

The use of spray gun

Add appropriate diluent and adjust to the appropriate viscosity

If the viscosity is too thick, the spraying effect will be too coarse. If it is too thin, it is easy to cause drips, affecting the next process;

The air pressure is best controlled at 0.3-0.4MPa

If the pressure is too low, the paint misting will be poor, and the surface will form pinholes. If the pressure is too high, it is easy to cause drips, and the paint mist is too big, which not only wastes materials, but also affects the operator's health;

The distance between the nozzle and the surface of the object is generally suitable at 200-300mm

If it is too close, it is easy to cause drips. If it is too far, it is easy to form pinholes. If the nozzle is too far away from the surface of the object, the paint is easy to scatter, which causes waste. The specific size of the distance should be adjusted according to the type of paint, viscosity, and air pressure;

The spray gun can move up and down or left and right

It is best to operate it uniformly at a speed of 20-30cm/s. The nozzle should be sprayed straight on the surface of the object, and avoid spraying obliquely.

Precautions of spray gun for coating spray

• Commonly used holding methods are to hold the spray gun with the thumb, little finger, and ring finger, and use the middle finger and index finger to pull the trigger. You can also hold the gun with the thumb, palm and little finger, and use the middle finger to pull the trigger and stabilize the gun with the index finger.

• Keep the gun perpendicular to the surface of the workpiece and maintain a reasonable distance. There are various radii on the surface of the workpiece. The key points for spraying the whole plate is to keep the spray gun and the working surface at 90° and move at the same distance and a stable speed as the surface. Otherwise, it will cause uneven coating, and the location where the coating is too thick may cause drips, while the area where the coating is too thin may cause leveling;
  

• The moving speed of the spray gun is usually 30-60cm/s, which depends on the type of coating and spraying requirements, and is also related to the overlap of the spray range. Generally, when spraying for the first time, the overlap of the spray gun is 1/2, and when it is sprayed for the second and third times, the overlap of the spray gun is 3/4 or 2/3. The moving speed of the spray gun should be moderate and stable. If the speed is too fast, the coating will appear too dry, and the leveling, gloss and clarity will be poor. If the speed is too slow, the coating will become too thick and drips will occur;
  

• When spraying the base color, the gun is often moved quickly with 1/2 overlap to spray a thinner coating. When spraying for the first time, the nozzle position of the spray gun should be aligned with the upper edge, and when moving in the opposite direction for the second time, the nozzle position should be aligned with the lower edge of the first sprayed coating, and the overlap range is 1/2;
  

• The spray route should be carried out in the order from high to low, from right to left, from top to bottom, and from inside to outside. First spray the corners or edges and then start spraying from the top of the workpiece.