I spray paint with gloss using rattle can on a model and it made the car glossy but some part of it was not. Today when i got home I sprayed it again outside and weather was around 65 degree and while drying I noticed that what was once gloss became flat. Only thing I can think of is due to the weather but I could be wrong.
I don’t know about cold, but humidity can cause gloss paint to get a white, flat coating. This is called blushing, and happens mostly with faster drying paints, though enamel can do it too. Usually cold reduces humidity, so blushing is less a problem in the cold weather. Cold can make enamel very slow drying, however.
Sometimes a rough undercoat or un cured base coat will cause the gloss paint to bite in too much and lose its shine. Don’t think it was the temperature.
Blushing is caused by condensation of water on the surface of the paint before it’s cured. Note that it can be exacerbated by painting outdoors (or in an otherwise cold environment) and then taking the painted item indoors (or putting it in a warmer place).
Phil_H that sounds like what happened in my situation. After painting it I brought it in the garage to let it dry and notice when drying that it looks flat but the paint at the bottom edge of the model still has the gloss.
As a followup I heard that you can removed the dull of the paint by heating it. Would that work with a dryer on a model will it affect the plastic?