The whole car has been sanded to 180 grit, and the surface feels smooth but you can definitely see the small sanding scratches, and the roughness of the crosshatched scratches. There are no bumps or ripples or dips in the paint anywhere. Now it is time to block-sand to 400 grit. The 50 foot roll of sandpaper (the same width as my sanding blocks) is $15. I also had to buy a new rattle can of guide coat ($6) since I put waaay to much of it on the car before blocking to 180.
Here you can (maybe) see the difference between 180 and 400 grit sand scratches. The mirror on the left is sanded to 180, the one on the right is to 400. You can feel a distinct difference.
Here you can see the light just right on the front fender and barely make out the scratches. Most what looks like scratches is actually where dust left on the paper has slightly burnished the primer.
Here is an even closer close-up. in the gap on the hood you can see how big the texture of the primer originally was.
Here is a look at the car well on its way to being sanded to 400 grit all around. You can still see dark gray spots from where I've gone through the primer and etch to bare metal.
Here is the sunroof at 400 grit. You can see how much better it looks than before when it was all scratched and gouged.
Again the work was spread over a few days so here's what was done and how much time was spent.
10-27: 7 hrs (3 hrs: drivers side and hood; 4 hrs: passenger side, pillars and roof)
11-1: 2 hrs (1 hr: tail of car; 1 hr: all the parts - bumpers, mirrors, sunroof, spoiler.)
Blocking from 180 to 400 was really fast. The only hang-ups were that the guide coat, which I put on too heavy again, gummed up the paper pretty badly. I decided to go over most of the car quickly with a big block (12") just to knock off most of the guide-coat, switching quickly, and then went back more carefully with pristine paper. Also the paper would get loaded with dust pretty quickly. Again, I would rub the paper once or twice across the bluejeans on my thigh and the dust would fall right off without creating huge clouds of billowing dust.
Total time spent: 9 hours (over two days)
Total money spent: $15 (for a roll of 400 grit Indasa RhynoDry 2 3/4" x 25 meter PSA paper.)