We offer epoxy filler primer in our eBay shop. This creates rust protection and a filler structure at the same time. As a rule, these primers or fillers are grey. But that doesn't always work. For example, you should use a white filler for red top coats so that the red tone has a higher brilliance. Likewise, light-colored basecoats or paints with a high pearl content often have low opacity. A primer or the epoxy filler in the subsequent color is required there. Likewise, almost every new car today is already pre-treated on the assembly line with a colored filler, which is also cheaper for small impacts, since the lower layer is the same color as the upper layer of paint. A filler in the color of the car also reduces the amount of final paint required because it covers faster. Vehicle paint.