Hi there pupjoint
It is very adviseable to paint plastics - especially the styrene type. This is because some UV light is found in sunlight and is emitted by electric arcs and specialized lights such as black lights. Most ultraviolet can be classified as non-ionizing radiation, and can cause chemical reactions, by hardening the plastic which then becomes brittle - this also happens with age. So, always best to put a barrier in place to try and prevent this and paint, I feel, is one of the best barriers.
aye
john
