An assembly device is disclosed for attaching first and second hollow frame members together. The assembly device includes a hollow base member having a top wall, four sidewalls and an open bottom surface. The base member also has a hollow tube positioned therein. The assembly device also includes first and second hollow coupling members projecting outward from a top wall and a side wall of said hollow base member. Each of the first and second coupling members has four sidewalls and one or more cavities formed therein. The cavities allow an expandable adhesive that is placed therein to contact the inner periphery of one of the first and second hollow frame members once the first and second hollow frame members are slid onto one of the first or second coupling members. The expandable adhesive will hold the first and second hollow frame members secure to the assembly device.