My newer helmets came with instructions against painting them., although sometimes the lawyers force the companies to make policies overly safe. I think one of mine is ABS and other is polycarbonate.
My old Arthur Fulmer from 1980 is fiberglass- I'm sure that one is OK to paint.
Your helmets look really cool! Nice job!
Arthur Fulmer helmets used to be made in Miami FL. You could go to the factory and buy seconds. Nothing safety-wise the matter, of-course. Blemishes in the finish. Unless you looked really-hard, you'd probably never-see it/them. A great way to get a good helmet.
If I were you, that Fulmer would be going on the shelf and replaced with something new. A 41 year-old helmet should have been replaced 8 generations back. So-say the manufacturers. After-all what's at stake? CTE? Or worse.
I have one of these, and when I replace it, I'll buy another. I've had BMW and Shoei modular helmets and the Shark is the best. The way you can wear it as an open-face, and in a couple of seconds, it's a full-face, is an amazing invention, and it's rated for use as either. No-feeling like the hand of God is trying to rip your head-off as you get-up to freeway speeds with it open, like the others would feel/behave.
EVOLINE SERIES 3 Modular Helmets | SHARK Helmets North America (shark-helmets.com)
Another point (no, not my head!) is that while a matte black helmet may give you that menacing look, a plain white helmet makes you highly-visible much further-away. That's a significant safety consideration.
I suggest a comparison. How often/how soon do you replace tires on your motorcycle? On a bike like your VMax, what is the effect of riding on old, hard tires? What happens to the handling in corners? Even if it's not showing cord, riding on old tires on a VMax is scary. Now, what's more-valuable to you, your bike, protected from damage by tires in good-shape, and say, < 5 years old, or your head, protected by a 10 year-old (or much-older) helmet?
