An adhesive composition includes a first part comprising about 15 to about 60 wt % of an epoxy compound, about 35 to about 80 wt % of an epoxy novolac, and about 5 to about 25 wt % of an epoxy-based reactive diluent based on the total weight of epoxy compound, epoxy novolac, and reactive diluent; and a second part comprising less than about 20 wt % of a hydroxyaromatic solvent, about 80 to about 99 wt % of a Mannich base, and about 1 to about 20 wt % of a tertiary amine, based on the total weight of hydroxyaromatic solvent, Mannich base, and tertiary amine, the first and second parts being present in a volume ratio of about 0.8:1 to about 1.2:1. Additives to further enhance the properties may be included. A method of forming an adhesive layer includes applying the adhesive composition to a surface.