Kern raises an interesting point. I’ve never thought about paint cracking like that from cold, and had to ponder it for a moment. Here goes another rambling post, just like the old days…
I paint for a living, have for about thirty years. Mostly industrial equipment, but have done semi trucks and a few cars. And as I go to annoying lengths to show, it gets cold here. But we also have strong spring sun, so that a dark vehicle can have water running off it despite it being twenty below. So body panels really expand and contract as the sun then shade hits them.
I’ve only ever seen paint crack like that from poor surface prep, and not as a result of temperature. In one case that I was responsible for it did exactly that sort of cracking over areas of bondo that had a wrong primer applied.
Where extreme temperature shifts seem to screw your paint job is around the edges. The panel shrinks, and exposes metal that wasn’t painted that was under gaskets or masking. Steel doors with a window in them are notorious for this.
On an unrelated note, I’ve seen many metal clad buildings built in the cold. When summer comes along all of the metal cladding goes wavy as it expands in the sun. Looks bad.
It doesn’t seem to happen as frequently now but large sun roofs and back windows on SUV’s used to explode with regularity when those heat traces to defrost them made some parts of the glass expand differently then the glass that didn’t have the heat trace. Sounds like a gun going off and can be disconcerting when your sunroof crumbles onto your head. And then you have to figure out how to seal the opening when it’s dark and forty below.
