In a bid to update my 90s metal double glazed doors and delay the inevitable replacement I have decided to paint the door frames black. It's going quite well, all areas masked off and have currently done two coats in Rustoleum Universal Paint Matte Black. I would like to have grid lines, Crittal style, but am unsure how I can go about this? I'm think glass paint, wooden trim or even black electrical tape. Anyone got any ideas or had any success they can report back on?