So I am going to try a bottle cap mural this year (hopefully this fall if I can get enough caps collected). Have any of you done this project for an outdoor piece? I am going to have my students work on a 7 ft tall...3ft wide(on all 4 sides) box. This will go around the pole that holds our school reader board sign up (a sign & pole I feel is super boring/unattractive). I was thinking about using caulking?!? Any other thoughts??? I want it to survive the winter...into the spring. Any tips/experiences shared would be welcomed!