During electrolysis for rust removal, a small electrical charge from a battery is sent through the rusted ferrous metal that is submerged in an electrolyte solution. This simulates the interchange of ions between the negatively-charged metal and a positively-charged anode, eventually getting rid of all iron oxide.
Did You Know?Electrolysis has been used to separate many elements from impurities present in their natural form, since the 17th century. Most notably, Martinus van Marum's electrolytic generator in 1785, which effectively separated tin, antimony, and zinc from their respective salts.
Although removing rust with electrolysis on a large-scale can prove tedious and require complicated machinery, home users who need to clean rusty tools can do the same thing quite easily. This process is good for antique collectors too, as electrolysis does not remove the patina that is very necessary to maintain the appearance and price of the article. Another advantage that electrolysis has over brushing, grinding, or other conventional rust-removal methods, is that none of the original iron or steel gets removed, and the process is usually not caustic or noisy, besides being comparatively inexpensive.
- This process requires the least manual labor.
- If more than one object has fused together by rust, electrolysis can break these bonds of rust and separate them from each other.
- Unlike other methods, electrolysis can clean rust in the smallest of corners and crevices.
- Other chemical treatments, such as acid baths, can damage the metal. However, there is no such risk with electrolysis.
- Most abrasive rust-cleaning techniques cause scratches on the metal surface. There is no such problem with the electrolytic process.
- Wear clothes that cover your body well, and use a thick pair of gloves. You will also need a pair of safety goggles and a face mask.
- Always work in a properly ventilated area. This is because electrolysis can create volatile oxygen and hydrogen gas, and sometimes even toxic fumes.
- Don't touch the liquid electrolytic solution when the power is on, to avoid getting shocked.
- Never leave the area unattended while the process is underway.
- Keep the apparatus away from children and pets.
- Never cover the plastic container, as it can cause overheating and burning.
- Never light a flame or cigarette near the apparatus, to avoid explosions.
- Any spills on the skin or eyes should be washed immediately, and medical treatment should be administered if necessary.
Electrolysis Setup for Rust Removal
- Washing soda
- Car battery/battery charger (12 volts)
- Strong plastic container (big enough to hold the rusted article)
- Plate steel/graphite (large chunk)
- Charger cables,with safety clamps
- Ammeter (if using a car battery and not a charger)
- Wire brush
- Scotch cleaning pads
- Distilled water
- First prepare the electrolyte liquid solution, which is made with the ingredients of washing soda and distilled water. Pour some distilled water inside the plastic container, and add approximately a tablespoon of washing soda for each gallon of water, and mix well.
- Unplug the battery/charger, and use the ammeter to set it at 2 amps.
- Fix the red cable clamp to the plate steel/graphite anode. Affix the other end to the positive terminal of the battery/charger. Similarly, attach the other black clamp to the rusted object, and the negative battery/charger terminal by the other end. Getting the polarity right is extremely important. If the connections are wrong, the rusted object will become the anode, and will cause damage.
- You must make sure that the two wires never connect during this process. Put the anode and the rusted object inside the electrolyte solution. The power clamps should never touch the water, or they will get corroded.
- Plug the battery/charger back and check the ammeter. If the reading is significantly higher than 2 amps, or if you see signs of smoke, unplug it instantly.
- If the reading shows 2 amps, then let the rusted object rest in the solution. You will notice that the object has started to fizz. Depending on the size of the object, it might take an hour or more to stop. If there is a lot of rust, a reddish layer of scum will form on top of the solution. During this period, the anode will slowly transfer its molecules to the other object, and will gradually lose shape or become coated with rust.
- If you find the anode has become too dirty and is disturbing the ammeter reading, disconnect and clean it before fixing it back.
- Once the object stops fizzing, unplug the battery/charger and carefully take the cleaned object out of the solution.
- Use a wire brush and cleaning pad to clean out the black slimy coating.
- You should now have a nicely cleaned rust-free article. However, it needs to be thoroughly wiped dry immediately, or a thin new layer of rust will start forming on it.
- Wax, paint, or oil the object to prevent any future rusting.
- Safely discard the water, and pack up your electric apparatus. Your electrolysis procedure is now complete.
- If the rust is stubborn and remains even after the electrolysis, use some hydrochloric acid, followed by another electrolysis session.
- Most experts believe that graphite is a better alternative than steel to use as an anode.
- If the process suddenly stops working while the rust removal procedure is still underway, check the electric connections. This is the most likely source of the problem.
- Using a larger container will give you a better overall result.
- Don't try to clean the corrosion of copper, bronze, silver, or lead with this procedure. This is because, any rust formed on such objects is not ferrous, and electrolysis will not work on these materials.