How to judge the sheet metal or paint with the paint thickness gauge?

The used car price differs a lot due to different factors. And we often see the artifacts in the hands of the appraiser - the paint thickness gauge. The paint thickness gauge, also known as the coating thickness gauge, is a tool specifically designed to detect automotive paint coatings.
     Therefore, we can use the paint thickness gauge to detect the thickness of the car paint surface. The tested paint thickness value can help us judge the sheet metal and paint conditions of a car. It is even possible to help us know whether this car has a serious accident or not.
     How do we judge the sheet metal or paint with a paint thickness gauge?

Linshang LS220 paint thickness gauge

First let's take a look at what is sheet metal? Sheet metal is a cold working process for sheet metal including shearing, punching/cutting/compositing, folding, riveting, splicing, forming, etc. The thickness of the original paint of most cars is between 120-180 microns. Of course, the thickness of the paint film will be different according to the cars of different brands. We generally take a place (car roof) where the scratch collision is not easy to occur as a base point to measure its value. 
   After taking the base point value, we start measuring other positions of the car body. If the measured value is just a little larger than the car roof paint thickness, we will judge it as painting. Because the car surface will only peel off the paint when it is slightly scratched, we only need to make up the paint. If the measured value is larger than the base paint thickness, it may be that the collision has caused the vehicle to deform and use the sheet metal.