Abstract: The invention relates to a low density two-component structural void filling composition that is preferably based on epoxy chemistry. It is designed for use on interior honeycomb sandwich structures as edge close-out and corner reinforcement, as well as local reinforcement for mechanical fixation or complex gap filling. The composition is compatible with metal and non-metal constructions that are typically found in aircraft interiors. The cured material has excellent fire, smoke and toxicity properties. Further, the composition has excellent processing attributes due to easy storage, handling, extrudability, filling, grinding, and painting abilities.