At the risk of repeating myself. To get the same finish on the edge of MDF as the face you need to sand it through grits 100, 200, 300, 400 (or similar numbers) I use a rotary sander to do this but I guess it works with random orbital.
No need for primers etc. just sand to 400 grit and your good.
I always knock the corners of my mdf stuff before painting, either use a router or a plane or sanding block depending on how accurate you need it to be.
I did some MDF boxes with 45 degree joints, thanks to the festool track accuracy they came together very well. Joined with the tiny dominos. Expensive method in tools though.
At the risk of repeating myself. To get the same finish on the edge of MDF as the face you need to sand it through grits 100, 200, 300, 400 (or similar numbers) I use a rotary sander to do this but I guess it works with random orbital.
No need for primers etc. just sand to 400 grit and your good.
I always knock the corners of my mdf stuff before painting, either use a router or a plane or sanding block depending on how accurate you need it to be.
I did some MDF boxes with 45 degree joints, thanks to the festool track accuracy they came together very well. Joined with the tiny dominos. Expensive method in tools though.