April 23rd, 2011, 8:00 AM: I recently acquired three cast iron skillets in need of restoration. Two of them were purchased at antique stores in New York, and these are nearly one hundred years old. The third is a 12-inch skillet given as a gift (wow!); while it's a sturdy pan, there are some rust marks on there that need to be removed. While the vinegar method proved effective in restoring an iron grill recently (see Restoring a Cast Iron Grill with Vinegar), I've been intrigued by a mysterious method used for restoring old iron -- a method using that strange stuff known as "electricity." So, I decided to set up a process to restore these old pans with electrolysis: using an electrical current to remove the corrosion from the pan.
For my first attempt, I'm using a Wagner 6-inch skillet. As you can see from these photos, the surface metal of the pan has a copper color to it -- I presume that's oxidized metal, but the sheen looks more like copper than rust.
- A Wagner cast iron skillet (circa 1922) in need of restoration.
- I presume the copper coloring is oxidation of the metal.
The best document on electrolysis is here: http://www.wag-society.org/Electrolysis/rust_redct_elect_setup.htm Using this method, I went out and found the parts needed:
- Equipment needed for electrolysis: battery charger, washing soda, plastic tub, cheap metal pan. Additional accessories: extra jumper cables, plastic dish rack.
None of this was very expensive. The most expensive item here is the battery charger; but if you wanted to do this on the cheap, I don't see why you couldn't get a 12-volt power transformer plug at Salvation Army or a dollar store, and use jumper cables to attach it to your pan. (If you do this, be sure to use a surge protector.) The washing soda (not baking soda) costs $3 at Stop & Shop and can be found in the laundry detergent aisle. The extra jumper cables ($5 at Family Dollar) are there so I don't have to connect the battery charger directly to the metal; the contact points are going to collect gunk and maybe corrode, so I'll eventually have to replace the jumper cables. The metal plate is the "sacrificial anode:" it's meant to attract corrosion, and eventually it will corrode and be eaten up by the electrolysis process. That cost me all of one dollar at Dollar Tree. The plastic dish rack is also from Dollar Tree; I'm placing the pan in there to keep it from touching the metal plate. The positive (metal plate) and negative (iron pan) contact points must never touch, or else the current will flow through them and eventually ruin the pan.
And so I put it together, added about half a cup of washing soda, filled it with water, attached the clamps, and turned it on. It took a few minutes before the battery charger started giving current; I think it was just because it was a brand-new charger and it needed to build up a charge itself. But once it did, bubbles immediately formed on the pan.
- The jumper cables connected to the battery charger, sitting on the plastic cover of the tub for insulation.
- The actual process is being done outside on my balcony, to provide lots of ventilation. The process produces hydrogen gas, which is VERY flammable!
Here it is on YouTube: http://www.youtube.com/watch?v=C6hpoiGASI4
Now in a few hours, we'll see how it turns out.
3:30 PM: About five hours into the electrolysis treatment, I figured that was enough; the pan wasn't in too bad a condition in the beginning. So I spent a few minutes briskly going at it with steel wool...and THIS is the result!
- Cast iron skillet after five hours in electrolysis, and five minutes with steel wool.
- Bottom of a restored Wagner 6-inch skillet.
Now all that's left is to season it...and cook!