The act of turning stainless steel black is called "bluing." Bluing chemicals used to require a heat source to work. Because heating these chemicals was bad for the environment, new chemicals have been developed to turn stainless steel black or brown. A black oxide kit gives anyone the ability to complete oxidation on metal surfaces and achieve a professional quality appearance. Bluing, commonly used to change the colour of gun barrels, is used when the chrome-like colour of stainless steel is not desirable.
Pour 28 ml (1 oz) of black oxide concentrate into a plastic bucket for every 255 ml (9 oz) of distilled water you plan to use. Then pour the distilled water into the plastic bucket maintaining a ratio of 9:1. If you plan to use 4.5 litres (1 gallon) of water, add 404 ml (14.22 oz) of the concentrate per every 3, 636 ml (128 oz) of distilled water. Otherwise, use 28 ml (1 oz) of concentrate per every 255 ml (9 oz) of distilled water. Pouring the water over the black oxide will adequately mix the black oxide and the water together.
Hang the stainless steel off a metal wire and suspend it into the fluid until it turns your desired shade of black. Do not touch the concentrate with your skin. Do not soak the stainless steel for more than three minutes or you can damage the structural integrity of the stainless steel. If you want a shinier finish or a less dramatic black, you can burnish the stainless steel before applying the sealer by buffing it with #0000 steel wool.
Dry off the stainless steel with a lint free cloth. Again, take caution to avoid getting the solution onto your skin. Rubber work gloves will help with this.
Place the penetrating sealant provided with the black oxide kit into a clean bucket. Dip the stainless steel into the liquid. Wipe the stainless steel with a clean, lint-free rag to remove the excess sealant. Allow the stainless steel to dry before using it for its intended purpose.