Prepping Ringo's Interior Metal

Last night I spent some time sanding all of Ringo’s interior red surfaces in preparation for priming. I’ve decided I’ll use Rustoleum rusty metal primer and apply it with a foam pad. My hope (and prayer) is that I’ll be able to lay it down smoothly enough to preclude any sanding before spraying the finish coats of satin black Rustoleum. My real hope (and REAL prayer) is that it goes down so nicely with the pad that I’ll be able to put on the finish coats with the pads as well. The masking required to prep for spraying is probably as bad as what I had to do before painting the outside. I truly don’t want to go through that again.