I am repairing a plastic bumper gash on a black van and, this being my first attempt at finish work, I primed, painted, and clear coated to the tape. Now I have a hard tape line that looks and feels like a ridge of primer. My plan is to attempt to wet sand the line with 2000 and then progress down to 1000 paper. Is that the right approach? If that doesn't work, what then? If I had it to do again I would have back taped during priming and then removed the tape for base and clear coats.

I suppose I could just sand with 400 down to primer, prime to a backtape line, color spray a larger area than the repair, then clear coat that larger area. But if there is another remedy, please let me know.

The only real professional way is the sand the whole bumper with 1000 grit. Sand your hard lines down with 600 grit and repaint those spots and re clear the whole bumper. However you can do the following if you want to do a spot repair.

Sand a larger area with 2000 grit paper. Then sand your hard lines down with a 1000 grit. Repaint/blend your base slightly past the line you created. Then clear the 2000 grit area with 50% clear 50% reducer. Then Spray your edges with straight reducer lightly.