An investigation of the factors affecting the wedge test performance of aluminum joints, prepared by bonding Al2024-T3 clad with FM300 epoxy adhesive, was conducted. It identified a number of factors whose influence was quantified in a regression model. The wedge test specimens were then machined into simple overlap fatigue specimens and cycled at a maximum stress of 20 MPa in shear and an R-ratio of 0.5. The results show that the log of the fatigue life is negatively correlated with the length of the crack produced in the wedge test. They also show that the scatter in the log(fatigue life) decreases with crack length in the wedge test so that specimens which had the shortest crack in the wedge test had the longest fatigue lives with the least amount of scatter in the fatigue life data. The decrease in the scatter is important in establishing confidence in the bonding process. (C) Koninklijke Brill NV, Leiden, 2009