What are the basic skills of car painting?

2019-11-21 11:48:18

There are three main factors that affect the appearance of the car: the color of the car, the texture of the top coat and the condition of the top coat. Especially the color is the basis of judging the quality.

(1) factors affecting automobile color: the definition and description of color mainly includes three concepts: brightness and hue: brightness refers to the brightness of color; hue refers to the color seen by human eyes; chroma refers to the intensity concentration of color, including intensity, concentration, saturation, gray degree, etc

In fact, different light sources have different effects on the paint, making the color of the paint change. This is because the amount of color light in the light source is different. For example, a certain paint contains blue component, which may not be seen in the sunlight, but it is very obvious in the mercury lamp. Because the content of blue light in the sunlight and mercury lamp is different, it may appear in the workshop light that the repair paint matches the color of the car very well, but it is not good enough in the sunlight. There is a great relationship between the color of the light condition in the workshop and the type of light used in the workshop. For example, incandescent light will make the paint red; different fluorescent powder in fluorescent light will make the paint yellow or blue; cold white light and soft white light can change the color of the paint

Sometimes the paint formula of repair paint is not the same as that of the finish paint formula used by the original automobile manufacturer. Even if the repair paint matches the original finish paint well in sunlight or simulated sunlight, it may not be the same in another light source

(2) identify the color of the original brand automobile: the first step of color matching is to obtain the original color according to the paint code of the automobile manufacturer, so as to reduce the difference between the repair paint formula and the paint formula used by the original automobile manufacturer. The paint code of almost all brands of automobiles can be found on the location map of various automobile brand paint codes. Repair color compilations are available on the market. This kind of book includes almost all color cards and pigment materials of brands and models. First find the paint code of the automobile manufacturer, and the color card is next to the paint code. In order to be safe, compare the color card with the color of the car itself, because some cars may have been painted with other colors

(3) determination of the type of original paint

1) visual inspection. If the skin tissue near the exterior line of the car body is rough, or the "polished tissue" appears after the paint surface friction, it means that the original polished paint is used

2) solvent method. The paint film was rubbed with a white cloth dipped with nitrocellulose paint release agent (banana water) to observe the dissolution degree of the paint film. If the paint film dissolves and leaves a mark on the cloth, it is self drying paint; if not, it may be baking paint or two-component paint. Acrylic polyurethane paint is not as easy to dissolve as self drying paint, but sometimes the solvent can infiltrate and weaken the surface luster

3) heating method. First, use fine sandpaper dipped in water to polish to make the paint film lose luster, and then use infrared lamp to heat. If the passivated surface is glossy again, it means acrylic paint

4) hardness test method. The hardness of paint film is different after drying. Generally speaking, the film hardness of two-component paint and baking paint is higher than that of self drying paint. The commonly used method to determine the hardness and thickness of paint film is to use electromagnetic thickness gauge or mechanical thickness gauge

(4) paint color calibration: according to brightness, tone and chroma, the process of determining the relationship between paint and car color by graphic method is the color calibration. Color calibration is meaningful only when the car itself is compared. Master and apply the color calibration method, and distinguish the differences in brightness, hue and chroma

Color calibration is helpful to understand the paint formula, including those color matching base materials. However, it must be noted that the color matching may not be exactly the same as the actual color of the car, because the finish of all cars will gradually change over time, some will become lighter, some will become darker. For example, the yellow color fades quickly. If it fades to beige, the pigment should be lighter; if it fades to green, which is composed of blue and yellow, the pigment should be bluer, usually darker

Color matching of automotive touch up finish

Due to the different color composition and illumination degree of the original automobile finish, the fading degree of the automobile is very different. For example: the color of cars stored in the garage fades slowly, while the color of cars parked on the roadside and under the trees fades faster; in the Northwest Plateau, the color of cars changes rapidly due to the strong UV radiation in the sunlight; in the industrial and mining cities, the color of cars used due to the strong acid fog has a greater impact. Therefore, in the process of color matching, the change of fading finish should be considered. Generally speaking, the color of the new car fades fast in the first few months, and then it slows down

(1) preparation before color matching: color matching is an important part of color matching for automotive touch up paint. If you understand the color matching theory, understand the influence of the surrounding environment on the color, and draw up a complete mixing procedure, you can make a routine procedure for the spraying process

There are three basic purposes of color matching:

1) adjust the subtle difference between the repair color paint and the original automobile paint to make them match

2) match the touch up paint with the faded car finish

3) in case of no formula or paint code, prepare the car repair color paint.