Abstract: Methods and apparatus for detecting imperfections in adhesive coatings formed on fingers of beams are disclosed. The present invention relates, in one aspect, to a method for preparing a first work piece for joining with a second work piece. The method involves forming a finger in the first work piece, then applying an adhesive coating on the finger. A determination is made to determine whether the adhesive coating is defective through the used of a sensing mechanism which is arranged to scan across a portion of the finger. In one embodiment, a defect in the adhesive coating on the finger is defined as a void.