Gunmetal is similar in appearance to the natural bluing that occurs to metal, including firearms, after years of exposure to heat. Achieving this dark blue, oxidized finish on the metal products around your home, including stair rails and metal sconces, is possible with metal finishing gel. The gel is applied to a clean surface and allowed to react with the metal until the desired depth of color is achieved. Before the first drop of finishing gel is applied, prep your metal to prevent any unwanted discolorations or imperfections.
Wipe down the metal surface with a dry cloth to remove any loose dirt, dust and other debris from its surface. Create a mixture of 1 cup white vinegar, 2 cups water and 2 tablespoons baking soda in a plastic spray bottle.
Replace the bottle's top to incorporate the ingredients before covering the metal with a healthy coating of the homemade cleaner. Work the cleaner into the metal with a plastic scrub brush to remove any oils and other difficult stains from the metal. Dampen a kitchen sponge with water and wipe down the metal to remove the homemade cleaner. Dry the metal with a rag.
Slip on a pair of rubber gloves, safety goggles and a dust mask before applying gunmetal finishing gel to the metal surface with a foam paintbrush. Use even, back and forth motions to apply the product at room temperature.
Allow the product to sit according to the package directions, which is generally five to 10 minutes. Dampen a kitchen sponge with plain water and wipe away the product thoroughly. Allow the metal to dry and examine the piece. If the desired hue isn't achieved, apply an additional coating of the metal finishing gel in the same manner.