Ken I am no expert about paint but I did play one on tv. Wait that was someone else. Any way when I sold auto parts we also sold DuPont automotive paint. In my novice opinion the faded and chalky roof almost sound like some of the thinner/reducer is "pulling". This is where the thinner/reducer is the wrong temp for the time when the car was painted. What happens is the thinners/reducers get traped in the paint when it doesn't have time to evaporate normally. Then what happen 6 month to a year later is that the thinners "Pull" to the serface and cloud up the paint job. I don't know if this is really the case because I am thinking you painted the car all at once and used the same thinner/reducer for the whole job. This is just what it sounds like to me.

We had customer that would use the wrong temp reducers on perpose because he could get the paint to "flow" better. Well his paint jobs looked great for the first month or two and then the looked like primer.

As for the imron job I don't know maybe someone else can shed some light on it.

Good luck on your future painting projects.

Brian Moore
1949 3100 5 window Deluxe
"Today is better than yesterday, but not as good as tomorrow"