I've tried to fix some chipping paint and a tiny rust spot... and created myself a bigger problem:
I back-taped everything carefully... and still got these completely obvious lines - no blending at all. But this turned to be the lesser of my problems. I started 1000 grit wet-sending (gently and with a block), and the paint is coming right off. I'm only guessing that we're seeing the primer underneath it.
The paint job included 3 layers of primer, 3 basecoat, and 4 clearcoat (all from Automotive Touchup), with ample drying time between layers. The wet sanding I tried today... that was 3 weeks after the clearcoat. And yet it's coming right off, as if I applied no clearcoat and 1 layer of paint 10 minutes ago.
What is going on?? And how can I mitigate this?