A few years ago I stripped my metal galvanised garage door with a heat gun and repainted it with a coat of Galvafroid followed by grey undercoat.
At this point the door was about 40 years old (house built
1976) and this door had been painted twice since the original builders painted it, firstly by the previous owner who slapped on another coat of black gloss paint which I stripped off to bare metal about 20 years ago. I also used galvanised primer plus undercoat plus gloss back then. It was fine for over 10 years until the paint started cracking along the creases and folds in the door.
I then repeated full metal strip with Galvafroid but left it at the undercoat stage while doing other jobs (and dithering about demolishing the by now detached garage and having an extension).
The extension plans have now been abandoned but I notice that the primer+undercoat has cracked and is flaking off in many places.
I really don't want to strip it again. If I remove all the flaky/cracking bits and carefully feather the paint edges, what are chances of just touching in the bare galvanised spots with the correct primer, plus a new undercoat and gloss ?. Will this stop further flaking, or have I shot myself in the foot leaving it at undercoat for many years ?
Andrew