Evaluation of Titanium Bonding Surface Preperation Method: Sol-Gel AC-130-2

Testing was performed to compare Sol-gel, AC-130-2, and Picatinny Etch as surface preparation methods for bonding titanium substrates. Sol-gel is considered an environmentally friendly alternative to the Sikorsky Aircraft Corporation (SAC) Picatinny Etch process and is a simpler and more robust process with a larger supply base for manufacturing operations. Single overlap shear, T-Peel, tensile stress durability, double overlap shear fatigue, and force controlled constant amplitude axial ("dogbone") fatigue tests were performed at four environmental conditions using four adhesives. Data presented in this report shows the Sol-gel process to be equivalent or better than the Picatinny Etch process as a bonding surface preparation method. 1. Based on this data, SAC has approved Sol-gel as an alternate for Picatinny Etch on all non-primary structure titanium bonds and has begun work on a plan for phased implementation onto aircraft parts.