Heat variations are from the different binder platics used. The guncoating product doesn't "need" heat but can take weeks to cure at room temperatures. Not sure how well these products would react to different base metals, aka zamac casting with brass or aluminumum detail parts especially if those were "glued" on and might not do well with the electrostatic applicator.
enamel paints take a long time to cure at room temp. Dry to the touch is not want you really want. Baking the paint drives off any solvents trapped in the paint and cures the actual binder.
