This paper presents the results of a multidisciplinary investigation of The Armorer's Shop (North Carolina Museum of Art), a 17 th century painting on panel attributed to David Teniers the Younger of Flanders. The study was motivated by x-radiographic observations suggesting an atypical panel construction and by the discovery that the armor depicted in this painting is nearly identical to that of several other works, all but one of which are attributed to Jan Brueghel the Younger, a contemporary Flemish master and relative of Teniers. Stylistic analysis strongly supports the hypothesis that Teniers painted the background, figures and objects depicted around the armor, and that Brueghel completed the armor itself. A broad range of materials analysis techniques, including cross-section microanalysis, dendrochronology, and confocal x-ray fluorescence microscopy (CXRF), were used to establish whether the panel construction and palette composition are consistent with this hypothesis. Dendrochronology shows that the panel was fabricated from three distinct wood planks, and suggests that the smallest of these, the armor plank, was painted approximately twenty years before the other two. CXRF demonstrates that this plank was painted before being attached to the other two. To the authors' knowledge, this is the first report of a painting being re-used in this way, and the first evidence of collaboration between these two painters.