Keep in mind these types of videos are geared toward collision repair. This technique applies when you are trying to use the absolute minimum amount of materials (collision repair) with a piss thin layer of paint. It doesn't really apply if you are trying to do a quality long lasting paint job. It has no application in restoration work or anything high quality long lasting. In Europe they can get away with this due to the lower temps and less intense sunlight. In places here in the US, this minimum amount of clear would die in just a few years.