Black oxide is a finish applied to ferrous metals that provides rust protection. The black oxide finish makes the metal surface porous, enabling it to hold a thin layer of oil. It's the oil that prevents rust from forming on the metal. If you want to make a black oxide finish yourself, the cold-process black oxide system is a safe alternative. This is great for crafters who use iron alloys like stainless steel to make sculptures, statues, furniture, kitchenware, or decorative household items like candle holders and wine racks.
Things You'll Need
Powdered abrasive household cleaner
Rubber or latex gloves
Cold-process black oxide kit
Plastic or glass container
Plastic kitchen tongs
Sealer, penetrating or dry to the touch
Clean the metal piece you want treated with a wire brush or a powdered abrasive household cleaner. The metal piece must not have any traces of grease, oil, rust or paint.
Put on rubber or latex gloves.
Mix the black oxide solution as the product directions require. Mix the solution in a glass or plastic container large enough to hold your metal piece. If the product requires the addition of water, use only distilled water. Keep the mixture at room temperature.
Place the metal piece in the black oxide mixture. Do not drop the piece in the mixture, as this may cause the mixture to splash; instead, use plastic tongs to transfer the metal piece into the mixture.
Remove the metal piece from the black oxide mixture at the end of the recommended time. Follow the black oxide manufacturer's timing recommendation carefully, and do not allow the metal piece to remain in the mixture longer than recommended. Typically, the metal piece should remain in the black oxide mixture from three to ten minutes.
Rinse the metal piece with clean water and dry it with a lint-free cloth.
Apply the sealant recommended by the black oxide finish manufacturer. The traditional finish for black oxide is a penetrating oil-based sealer, and is applied by dipping the part in the oil sealer and wiping off the excess with a lint-free cloth. If you prefer a dry finish, check the manufacturer's recommendations for non-oil sealer options.
Allow the finished metal piece to rest overnight before use.
If you are unsure about the metal you are treating, apply a small amount of the black oxide in an inconspicuous place to gauge the results before treating the whole piece.
Use a gel paint-on black oxide product if your metal piece is too large to dip in the black oxide liquid. This is ideal for large craft projects like furniture or life-sized sculptures and statues.
Do not use black oxide on stainless steel, aluminum or chrome. Instead, use a blackening kit made specifically for these surfaces.