A method and apparatus for forming a joint between a first composite structure and a second composite structure. A number of tab sections may be formed at an end of the first composite structure. The first composite structure may comprise a first skin, a second skin, and a core located between the first skin and the second skin. A tab section in the number of tab sections may comprise a first skin section of the first skin, a second skin section of the second skin, and a core section of the core. A portion of the core section may be removed from each tab section to form a number of tabs at the end of the first composite structure. The first composite structure may be attached to the second composite structure using the number of tabs to form the joint between the first composite structure and the second composite structure.