WEll that all really depends on the goggle type. Some..most chem goggles usually are large and cover both eyes (unlike my cup style welding goggles that cover each eye sperately) this would imply that it has a rubber or flexible lining which touches your eyes...which means you wouldnt be able to spray paint it because the paint would just chip off. I would suggest cutting some leather to go around that part and then just staple or rivet it to keep it on.
Then cut some sheet brass to outline the eyelets. Then the rest is up to you...glue on gears...doodads..or w.e you cna find. Then maybe even draw some designs on the leather.
I dont know wether or not that was helpful or confusing...but good luck!