(This is part of a larger series on cleaning and seasoning cast iron cookware – See the Food Related Section for more information.
Cleaning and de-rusting cast iron cookware has only really two workable methods. The first is to clean in either a self cleaning oven then de-rust with either electrolysis or acid. The Second is to use Electrolysis to clean and de-rust.
Electrolysis for the home owner is a bit foreboding. There is electricity involved, as well as chemicals and hazardous gasses (The electrolysis process splits water into hydrogen and oxygen – each very flammable if not down right explosive). That not withstanding, a home electrolysis rig can be setup and operated safely for little or no capital outlay.
The objective is to immerse the cast iron in an electrolyte solution and to charge a metal object in the solution positively and the cast iron negatively so that rust and impurities are drawn from the cast iron object. Technical terms aside, this is actually very easy to do at home if you have a battery charger (you do don’t you?).
Here is how to make a simple electrolysis rig for about $30.
You need the following items:
- Large plastic tub (large enough to hold any cast iron object you want to clean and de-rust)
- Sheet metal to fit the bottom of the tub
- 1/4″ threaded steel rod
- Two bolts and washers to fit the rod
- A stainless steel hose clamp
- 3 Feet of non-coated steel cable (not galvanized)
- A plastic tray or scrap plastic to set your cast iron on, keeping it off of the steel plate
- Arm and Hammer “Washing Soda” (the basis for your electrolyte)
- A battery charger with at least a 20 Amp setting
- Wear Gloves
- Wear Eye Protection
- Only Perform Electrolysis in a Well Ventilated Area
- Do Not Leave Unattended (at least until you are familiar with the process)
How to Do it (see images for details):
- Use a hack saw to make the steel plate fit in the bottom of your plastic tub (I had to round the corners of mine)
- Drill a hole in the steel plate to allow the rod to pass through
- On each side of the plate, use a washer and nut (I used stainless steel as I would like to be able to take it apart after use)
- Put the assembly into the plastic tub and verify that it is a reasonable fit (adjust as needed)
- Place your plastic tray on the metal plate. If it is solid, drill holes in it so the current will flow around the object you are de-rusting
- Fill the container with water and add one to two table spoons of Washing Soda per gallon of water you use
At this point you are ready to use your Electrolysis setup. All you need to do is connect the positive lead of your battery charger to the rod connected to the base metal and the negative to a steel cable that you attach to the item you are going to de-rust. Be certain to use a length of steel cable that is not vinyl coated or galvanized. I bought a 1/4 thick braided cable at the local hardware store (the type you have cut to length).