Now it´s time for some sanding again. I´m using 120 and 180 grid paper with the orbit sander to clean the MIP front from any glue/leftovers/etc to make the surface smooth. Don´t forget to clean all the cutouts as well (use your hand ;))
As I´m looking for a very nice surface finish, I´ll treat the front with a primer first. The primer fills tiny holes and scratches and also closes the surface of the MDF. MDF tends to soak away color in no time thus it´s really neccessary to use primer or a base coat first, otherwise the surface will not look good and you´ll be disappointed. I found some primer in a spray can and I used it up till the very last drop as the MDF soaked in the primer. It´s important to take care of all the edges and change the spray angle and direction so everything gets covered. While the MDF soaks in the primer it´ll start to raise the wood fibres on the surface and especially on the edges.
It will look and feel ugly but wait for the result after sanding it down. After 6 hours of drying I used 400 grid paper and the orbit sander again and now the surface finally feels smooth. If you sand down too much and you can see the wood again, don´t worry, it´s soaked and shouldn´t be an issue. If you want to do it the safe way, you can apply a second layer of primer and add another round of sanding which will make the surface even more perfect. For the gauges I used 240 grid and the good old hand.
I applied the acrylic paint with the compressed air spray gun and gave it at least 2-3 layers of paint including one in-between sand-down. If you follow this simple steps you´ll end up with a very nice surface.