There are several effective ways of removing rust.
When oxygen combines with iron molecules, it forms iron oxide or rust. Since iron oxide molecules are larger than iron molecules, the surface expands and rust particles flake off. This allows more oxygen in, causing more rust to form. To preserve iron-based (ferrous) metal, you must eliminate the rust and protect the metal with a substance that keeps oxygen away from the surface. You can remove rust by physically scouring the metal, dissolve rust chemically or use a process similar to electroplating, called "electrolytic action." Choose the method you wish to use based on the type of metal and amount of rust on it. Does this Spark an idea?
Instructions
1. Scour surface rust off small components and tools with a rubber abrasive sanding block. Steel wool and emery paper also work well, but unlike rubber sanding blocks, these treatments won't remove rust from tiny crevices in the metal. Rub the surface until it shines, then apply a coat of paint or a protective layer of penetrating oil.
2. Rent or buy a sandblasting rig to remove surface rust from large areas such as automobile body parts or metal garage doors. Load the hopper with the grade of sand recommended in the instructions and start the unit. Hold the nozzle 10 to 12 inches away from the material and blast the surface clean with successive passes of the sandblasting wand. Apply a coat of commercially available acid metal wash followed by self-etching primer to prevent further rust from forming.
3. Coat rusted metal surfaces with a liberal amount of phosphoric acid and leave overnight. The acid will remove all traces of rust and etch its way into the metal, leaving a bright matte finish and a fine protective layer of iron phosphate behind. Clean the surface and apply a coat of paint or a thin layer of penetrating oil to prevent further rusting.
4. Coat the rusted article with a commercially available organic rust converter and let it dry thoroughly. These rust converters contain polymers that combine with rust and break the bonds between iron oxide molecules and iron molecules. Protect the newly cleaned article with a coat of paint or a thin film of multi-purpose penetrating oil.
5. Immerse larger convoluted components such as cast iron cylinder heads in a plastic container filled with an alkaline solution made up of 1 tbsp. of sodium carbonate per gallon of water. Place a piece of scrap iron in the bath without allowing it to touch the rusted article. Attach the negative terminal of a 12V battery to the rusted component and the positive terminal to the scrap iron and leave overnight; electrolytic action will transfer all traces of rust from the component to the piece of scrap metal. Hose down the rust-free component to remove all traces of alkaline solution and dry thoroughly. If you plan to assemble the component immediately, there is no need for an added protective layer of penetrating oil or paint.
Tags: rust from, coat paint, iron molecules, iron oxide, layer penetrating
