I have a new curbside mailbox made of steel which is painted in a slick enamel (standard mailbox as purchased from Lowe's). I want to put numbers on it, but don't care for any of the "stick on" numbers I've seen, and using stencils to paint on numbers is too much trouble and messy. I want to glue on either metal or plastic numbers. Descriptions of various glues sometimes say "metal," but that doesn't necessarily mean it's the best for my purpose. Does anyone know of the best glue that would work for painted metal and stay on during all kinds of weather?