CARBOMASTIC 15 PART B 1-GA|Carboline's Carbomastic 15 is an aluminum-pigmented, low-stress, high-solids mastic with outstanding performance properties and a proven field history. It can be applied over minimal surface preparation of steel substrates, as a topcoat over existing coatings or for field touch-up of zinc-rich primers and galvanized steel. Its unique formulation is made with aluminum flakes for exceptional barrier protection.