3M Impact-Resistant Structural Adhesive (IRSA) is formulated for true automotive OEM specified structural bonding applications, excellent for collision absorption in steel structures and advanced lightweight aluminum alloys. This two-part epoxy adhesive delivers extended work times, up to 1 hr and can be rapidly heat cured. The adhesive changes from silver to purple as the adhesive cures. Engineered to withstand much higher impact vs. traditional bonding adhesives, 3M impact-resistant structural adhesive (IRSA) is excellent for true OEM-specified automotive structural applications. It adheres to properly prepared automotive substrates including mild steel, high-strength steel and automotive aluminum alloys, vital as OEMs strive to achieve high strength in increasingly lightweight structures. Two-part epoxy adhesive is recommended for all weld bonded and rivet bonded joints when specified by an OEM. It provides an extended work time, as long one hr and cures rapidly with heat (30 min at 80 deg C). Adhesive applies in a silver color and changes to purple as it cures, indicating when the process has begun.