I painted a wrecker for a friend last year, He talked to me early last spring about the bubbling finish so I redid the front fender which is fiberglass. I used feather fill G2 over the fiberglass and sanded it then shot SPI regular build 2k over that then used SPI black base and Euro for clear. I saw the wrecker yesterday and it has another bubble on the same fender so this will be the third time I will have to fix it, I need to fix it right and need your help and advice.