The lazy way to remove rust : Electrolysis!
Everyone has some rusty items in their garage or workshop. In some cases its tools that have been exposed to damp conditions or in some cases its a car in thousands of pieces (many of which are rusty) as it undergoes a full restoration. Rust removal tends to be a job for wire brushes and elbow grease, but there is an alternative.
Even the most severe rust can easily be removed with some of the rust even being converted back to good metal. all that's left is a layer of black oxide that is easy to remove with just a light rub down. This is all done by the process of using electrolysis, and what's really great about electrolysis is that you don't need a lot of expensive equipment and technical know how to be able to convert a rusty lump into a cleaned up usable part.
Rust removal by electrolysis works by converting the Rust (Ferrous Oxide) into what is commonly called Black Rust (Ferric Oxide). Black rust is actually called magnetite or lodestone when found in its mineral form.
Things you will need
- Large plastic container (preferably square or rectangular and large enough to easily fit your rusted item into)
- 4 sheets of steel cut to the same dimensions as your container sides.
- Battery Charger
- Crocodile clips or other connectors
- Soda Crystals
- Wire/stiff nylon brush
Take your container and arrange the 4 sheets of steel around the sides, (you may want to fix them here with a bolt or glue if you intend to repeat this process a few times).
Connect the four plates together with some wire or other method ensuring a good electrical connection is achieved.
Connect the 4 plates to the POSITIVE side of the battery charger. DO NOT turn the charger on at this point.
Place your rusted item into the center of the tank and connect this to the NEGATIVE side of the charger. You may need to clean up a small area of the unit with a wire brush to ensure a good electrical connection.
Fill the tank with a solution of water and soda crystals. Your should should be of about 1/2 a cup of soda crystals to every 20 liters of water. adding more crystals will not speed up the process but will make the solution more electrically conductive and waste power and possibly blow the fuse on your batter charger.
Turn on the battery charger / power supply.
You should see bubbles forming on the rusted item, these bubbles are a mix of hydrogen and oxygen. This gas is highly flammable. However you shouldn't worry as the process does not produce a sufficient quantity to pose any danger. although it is still recommended that you do not allow any sources of ignition in the vicinity of the tank.
Leave the process running for several hours. after which you can remove the piece and give it a light scrub with a wire or stiff nylon brush under some water to clean off any deposits.
- This process produces highly flammable and explosive hydrogen gas, so it is best done outside, or in some other well ventilated area. Hydrogen is lighter than air, so it will collect near the ceiling - not sink to the floor like some other flammable vapors will . If you have open flames near this (ie. gas appliances like water heaters and furnaces which have pilot lights!) you may risk causing an explosion if the gasses are allowed to build up over time.
- Make sure the battery charger (or whatever source of power you use) stays dry. All of the usual cautions about any electrical device in a wet environment apply .
- The solution is electrically "live" - it is a conductor in this system. Turn off the power before making adjustments or sticking your hands into the solution. You can get a mild shock if you stick your hands into the water with the power on.
- The solution is fairly alkaline and can irritate your skin and eyes. Use gloves and eye protection. Immediately wash off any part of your body the solution comes into contact with with plenty of fresh water.
- Don't use stainless steel for the electrodes. The results are toxic and illegal to pour down your drains.
- Don't use copper for the electrodes and anything else that will be in the solution - the results are messy.