A method for making an activatable material having a handling film layer thereon, comprising the steps of providing a continuous mass of a polymeric material having a longitudinal axis and being capable of adhering to a metal surface; applying a handling layer (e.g., film) over at least one side of the mass; forming stress relief indentations in the mass, with the handling layer at least partially extending into the indentations, wherein the stress relief indentations allow a resulting part to be applied in conforming geometry with a surface to which it is applied. The teachings also contemplate parts made by the above method and use thereof to bond to surfaces having a non-planar portion.