My first impression when reading the original post is that materials were applied too heavily, then sanded too quickly, and after reading the rest, I still think that's it.
Even with the speed of 2K primers, the solvents still need to evaporate out of the paint film, and the heavier the film, the longer the wait to get the solvents out.
The initial 3 coats of primer were only given about 3 hours to dry before sanding, and then 2 more coats were applied, making a total of 5 coats of primer applied within about 4-5 hours of time. Then, a couple hours later, it was sanded again with fine paper for paint application, THEN it was allowed to sit for 2 days.
It's my opinion that the repair shrank over those 2 days, and that's why you're seeing repair rings after paint application.
To me, it would have been better to let it sit for 2 days, and sand it for paint afterward.
Everything posted about cleaning solvents is 100% correct, but I don't think it was the issue this time.
My 2cents
Tim Bowers
Stellar Antique Auto Restorations
