The right quarter panel took quite a bit more work than the left did. After block sanding, priming, and guide coating, the final sanding to make sure there are no sand scratches or waves in the panel is ready to begin. I’ve chosen to wet sand simply because I think it makes for a cleaner workspace but dry sanding works as well. I’m starting wih 320 grit and moving on to 400 on my way to 600. The second picture on the left shows the panel after the first rinsing. The second down on the right shows what’s left after the second sanding and all the residue has been rinsed away again. Notice how there is less and less of the guide coat as the scratches and low places are sanded out. Finally all of the guide coat is gone and there is a smooth surface ready to accept the finish coats of paint. A couple of notes here: First, if you sand through both the guide coat and the primer, there are a couple of solutions. If there is still guide coat left near the sanded through area, it’s likely more filler is needed. If not, more primer may fill in any low areas after more sanding to take down the high sanded through area. Second, again, now is a really good time to use the water to make the panel shiney and make a final check for straightness. It’s the last chance you’ll have before you paint and it’s a good mimic for the final coat.