[Dekatron]

I mentioned this problem with cracked dials at work and got a good tip from a colleague who had made fish hooks and other molded things - if you have an item that is cracked or has become rough on the surface you can spray it with clear lacquer and then sand it down with 1200 grade water sandpaper and then repeat lacquering and sanding until you have a smooth surface before making a mold to get a clean result, this is really important when using silicone based molding material he said as they otherwise will copy every crack and the rough surface.