Mask priming: sanding and filling

1) Spraying the first layer of primer onto the mask. This highlights the bumps and where needs to be sanded down, or built up a little bit more.
2) Close up of the detailing. The bumps are where I've applied the milliput and it still needs to be smoothed down.
3) After a few layers of sanding and filling: The grey paint mattifies after being sanded and more milliput has been built up in the areas that have dips.
4) After another layer or so of sanding, filling then spray painting, I circled the areas that needed filling to assist myself in remembering what areas needed attention.