How to Use Automotive Spray Gun

It is necessary to adjust the automotive spray gun before using it. Before spraying, the spray gun and related equipment should be clean and in normal working condition, and check whether the spray gun produces ideal spray shape. The ideal spray shape should be symmetrical, the atomization particle size distribution should be uniform and the edge should be clear. Only a small amount of paint mist is allowed to exist outside the spray shape edge. Low atomization pressure helps to generate the correct and uniform spray shape, as well as reduce rebound and over spray.

When holding the automotive spray gun, the spraying track should be vertical to the surface of the workpiece. When spraying, the distance between the spray gun and the sprayed surface is generally 15 to 30 cm according to the angle of the sprayed surface. The distance should be closer to obtain wetter, darker and thicker coatings, and farther to obtain drier, lighter and thinner coatings. During spraying, the angle of the spray gun to the sprayed surface shall be kept at right angles, and the running velocity of the spray gun shall be parallel to the sprayed surface.

The running velocity of the spray gun is generally adjusted between 30 to 60 cm/s, which is also required to be constant. If the spray gun is inclined and running in a circle arc shape or the running velocity is changeable, the paint film with uniform thickness will not be obtained, and stripes and black spots will be easily produced; if the spray gun runs too slowly (less than 30 cm/s), it is easy to produce sagging. There should be an amount of overlap, that is, coincidence rate, between adjacent spraying travels, and it should reach 50% - 60%. It is not easy to get smooth paint film when it runs too fast or the overlap is not enough. When the homogeneity of the paint thickness is required to be high, cross spraying method should be adopted, and after that the horizontal spraying should be carried out.