sanding primer before paint?

Daywalker wrote:

I knocked it down a lil' with a worn out scotchbrite pad

Since you have already done it the point may be moot, but make sure the paint is really cured or the Scotch-Brite can really get in there and take it off or leave some nice scratches.  That's how I do my winter camo.... a light wipe with the pad before the paint is fully cured.

Richard-

I am spraying a semi-gloss (Gunze-Sangyo) aqueous paint.  I knocked it down a lil' with a worn out scotchbrite pad (thanks Mike!) and am hoping to start painting it next week.  I'll post how it goes!

I always wet sand my primer with 600-1000 grit if I'm spraying a gloss paint, i.e.  auto models.  It really seems to make a big difference when I apply the topcoats.  Smoother finish,  and rubbing out the finish is easier.  Are you applying a gloss or flat paint,  or something in between?   

Frank, the only time I'll prime anything is if the top/finish coats are acrylics, and I'll use any MM light grey flat enamel I have handy at the time (I've yet to try Mr. Surfacer for priming). With the right thinning ratio & pressure they usually dry quite smooth and I can then proceed right to my top coats, but on occasion I've felt the need to lightly go over some areas with a Scotchbrite pad until I see a dull sheen. If I happen to sand down to the bare plastic (which can happen in the areas you mentioned), then I'll re-prime that area only if I intend on masking it and there is a risk of lifting the subsequent acrylic coats.