I'm assuming this is the correct forum for this question, so here goes.
Lately I've taken to constructing dioramas to display my crews at tournaments. I'm still new to this of course, so there are many things I don't yet know. For instance, how to present the display neatly and tidily on the outside. When building mine, I tend to use black foam-core. This means I end up with horrible strips of visible foam along the edges that shows up no matter what I do to cover it. So, I was wondering, for those who do, how do you achieve the lovely solid black on your diorama's outside walls?
For reference, the blacked edges on this marvelous piece is what I'm talking about: