Electrolysis is a simple and effective way to remove rust and restore metal without damaging the surface as sanding or scraping would. Electrolysis works best on iron and steel. Do not attempt electrolysis on stainless steel, since it can release toxic chromium gas.
How Electrolysis Works
Electrolysis occurs when a low-voltage, direct (DC) electrical current is passed through two pieces of metal suspended in a chemical (electrolyte) solution. The current causes a transfer of ions between the two pieces of metal which breaks down rust on the metal connected to the negative electrode (cathode) while corroding the metal connected to the positive electrode (anode).
Since electrolysis doesn’t affect the underlying metal, it’s perfect for cleaning tools, restoring antiques, and loosening rusted bolts.
Read on to find out how to remove rust with electrolysis.
Materials Needed for Electrolysis
Electrolysis should be done in an area with plenty of ventilation, since it releases small amounts of hydrogen and oxygen gases, which could be flammable if they build up.
To remove rust using electrolysis, you will need:
- Twine or Plastic Clamps: Used to suspend the tool and anode in the water.
Read on to find out how to set up electrolysis
Step 1: Disassemble Rusty Item
If the object comes apart, disassemble as much as you can. Plastic handles will probably do OK in the bath, but wood and leather should be removed or kept out of the water.
Step 2: Mix Electrolyte Bath
The electrolyte solution should contain one tablespoon of washing soda per gallon of water. Stir until the soda is completely dissolved.
Step 3: Suspend Rusty Item
Suspend the item in the solution so as much of the surface is exposed to the water as possible. I used twine, but you can also lay a board across the top of the container and hang or clamp your tool in place.
Make sure to use nonreactive plastic, wood, or twine. If the object won’t fit completely in the container, leave part of it out of the water and clean it in stages.
Step 4: Position Anode
Place the anode in the container so one end sticks out of the water. Position it a couple of inches from the rusty item, making sure they do not touch! You can also use twine or plastic clamps to hold the anode in place.
Step 5: Connect Negative Electrode
Connect the negative (black) clamp from the battery charger to the rusty item. If the item protrudes from the water, put the clamp on the dry part. While the negative clamp can to be underwater, it might cause it to eventually wear out.
Step 6: Connect Positive Electrode
Connect the positive (red) clamp from the battery charger to the part of the anode that’s protruding from the water, so the red clamp remains dry. Don’t get the two clamps mixed up, or you’ll end up with a really clean piece of rebar and a disintegrated tool!