Okay, so I feel a bit foolish here but I've got to be missing something. Today I bought some single wall black stove (6" x 24") pipe from Lowe's. The pipe is not connected to itself and it appears as if the one edge just slip into the other edge but it doesn't. Am I supposed to take a flat head screw driver and pry it, then slip the other edge in or is it just supposed to snap in? Anybody have any tips?