cast iron electrolysis tank for cleaning rusted metal
After acquiring several old rusted up pieces of cast iron cookware we decided to get a cast iron electrolysis tank. Some of the pieces were large, like an old dutch oven, so we wanted a large tank to accommodate it. We had a plastic 33 gallon drum that held syrup for beverages that would be ideal for our job. Any container that is not made from a metal will work. The contain must absolutely be non-conductive!
The sacrificial metal for your electrolysis tank
A quick search of the topic on YouTube will show you lots of different metals being used as the sacrificial metal. You will find everything from pieces of rebar all the way to pieces of old scrap metal.
To maximize the surface area available to attract rust from the item being cleaned I elected to use flat stock material. It increases surface facing the item to be cleaned. It also is easier to clean with a scraper and a wire brush.
Our cage was made so that when it is dropped into the tank it does not touch the sides or the bottom. Admittedly I don’t know if touching hinders the electrolysis process. I’m absolutely a novice at this and you should do your own research. With that said, I liked the idea of the solution being able to freely circulate around our cage. That is why it was built to not touch the container any where inside the solution
Cleaning the rusted item at regular intervals
While running our cast iron electrolysis tank I like to stop it every day to clean everything. My assumption is that using a brush to remove lose pieces of rust from the item being cleaned and the superficial metal will speed up the process.
I’ve been running the electrolysis tank on the old cast iron Dutch oven for awhile. Every day when i stop it for a quick cleaning I am seeing some great results. It still needs some more rust removed but the water was so nasty and rust colored I decided to start over with some clean water.
At the end of each day the Dutch oven has come out of the tank and scrubbed with a brush made for washing drinking glasses. The crud and rust that has come off after each scrubbing has been impressive.
The cage had a lot of rust built up on it when I removed it and dumped the water. Most of the buildup came off easily with a wire brush. While it was out we went ahead and hit it with the power washer. Hopefully tomorrow the cage will go back in the tank and we will fill it and see how it does with fresh water and sodium carbonate.
Removing crud from the sacrificial metal
This picture of the cage was taken AFTER it was quickly attacked with the wire brush. The bottom two steel bands looked just like the top one when this Dutch oven went into the tank.
This was taken at the end of the first day of removing rust from the Dutch oven. You should have seen the water at the end of day 3. That heavy number nine wire is suspending the oven in the tank and off the bottom. The negative connector goes on that wire.
While there is a lot of carbon on the bottom of oven in the next picture it is far better now than at the beginning. When we started the entire bottom and most of the sides were covered with it.
And finally here you can see the inside of the old cast iron. You can see the bottom of this old cast iron again! When you compare it the picture that was taken at the beginning you get an idea of how much rust was removed. There is still more work to be done, but I am satisfied with my setup. The battery charger has been running at 2 amps during the process so far. We could kick it up to 10 amp but I’m satisfied with doing this slow and easy.
The Dutch oven is out and I’ve dropped in a rough and rusted number 8 skillet. After an hour in the tank I found this on the top of the water.
You will need an automotive battery charger
Fortunately an inexpensive 12 volt battery charger works well for electrolysis. My go to battery charger is a dual amp capable of 2 or 6 amps. There are models available for less than $25 that will work for your electrolysis system.
You do not need a big and expensive battery charger to remove rust through electrolysis. However, if you already have one it can certainly be used.