A sticker for spacing wood is extruded from an aluminum alloy. The sticker can have different configurations. In a first configuration, the sticker has a width about the same as its height, with longitudinal ridges on all sides that grip wood when wood is stacked on the sticker. In a second configuration, the sticker has a width significantly greater than its height, with longitudinal ridges on the top and bottom surfaces, and with smooth side surfaces. The longitudinal ridges have a height within a specified range and are spaced at a distance peak-to-peak within a specified range. The ridges provide good grip of lumber stacked on the sticker yet do not easily plug with wood fibers through repeated use. The extruded aluminum sticker is very rugged and can be used for hundreds or even thousands of drying cycles.