Suitable for iron, steel, copper, brass, bronze, and other metals, Brush-on Presto Black®, Antique Black®, and Antique Brown® Gels are intended for post processing part touchup or on manufactured metal parts not suitable for traditional processing lines. Applied at room temperature, gels adhere to vertical surfaces and stay where applied without runs, drips, or bleeding onto adjoining surfaces. Chemical reaction takes 5–10 min following surface cleaning to remove oil, oxides, and welding flux.