Category: Cast Iron Restoration

Cast iron restoration techniques

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Electrolysis Tank-Cleaning Rusty Cast Iron

What is an electrolysis tank anyway? This is a method using a manual battery charger, sacrificial stainless steel, and an electrolyte solution that will clean rusty cast iron and steel items. An Electrolysis Tank uses the following materials:

  • A Manual Battery Charger, typically a 2/10/40/200 model. Make sure it’s Manual, and does not have the “-CA” designation after the model number, as that is not a true manual charger. You may have to order online. Do not bother with cheaper models or other power supplies, you want a battery charger with an internal cooling fan and enough power to run with stainless plates. DO NOT RUN YOUR TANK ON THE 200 SETTING. The 200 setting is only for starting a car.
  • A Rubbermaid or other plastic tub. More advanced users may find some kind of stainless tub and use that as the sacrificial anode. Plan carefully for what size you intend to use. Some simple math will calculate how many gallons of water you will be using . Also plan for what size anodes you will need for the tub.
  • Sacrificial stainless steel for anodes. Get some non-magnetic stainless steel sheets to fit your tub at a scrapyard, or purchase pre-cut online. 304 and 316 are recommended. Magnetic stainless will also work. Note that 316 is perfect for a corrosive environment. Note: I do not recommend regular steel. It wears out too quickly, requires frequent cleaning, and is not as effective as stainless. DO NOT USE GALVANIZED or COATED.
  • Arm & Hammer Washing Soda or other Sodium Carbonate product such as Ph+ for pools. Note this is not the same as baking soda. You can find this on the laundry aisle in most grocery stores.
  • Jumper Cables, or other means of connecting the plates. I simply purchased four sets of 4-gauge cables (try to get shorter lengths) and connected each plate that way. I’m not an expert in electrolysis, so I suggest you join this group on Facebook for other setups and more expertise: ElectrolysisTanks. Special thanks to Dru Humphrey and Wayne Boughan for answering all my questions.
  • And finally, some means of hanging and suspending the pieces, typically a 2×2 piece of wood for example from which to hang the piece; and coat hangers, stainless wire, etc., along with some C-clamps with no coating to hold the piece.
  1. Put together your tub and set your anodes in place, and fill with water and keep track of how many gallons you are using. You need to add 1/2 Cup washing soda per 5 Gallons of water. Warm water helps the washing soda dissolve. Add water periodically to your tank as it evaporates, you don’t need to add any more washing soda.
  2. Hook up your jumper cables, first connect your master positive red jumper on the battery charger to the first plate (red goes to sacrificial anodes). Next take another red positive jumper cable and put on the first plate, and then onto the second plate. Repeat procedure all around. Or connect plates in a more advanced manner.

  3. IMPORTANT

    Take the master negative black cable from the charger and attach it to the black negative end of one of the jumper cables, you’ll use the other black end to attach to the piece. This protects your battery charger cables from wearing out. Make sure when you connect the piece, you are using the other end of the black negative cable that is jumped to the main battery cable.

  4. Connecting the Piece

    Ensure your piece is not touching any of the anodes. Connect the correct black negative jumper to the piece, I use a DIRECT CONNECTION ONLY. Some people will connect the jumper to a wire, but I do not recommend it. It’s okay if the jumper goes in the water a little. Ensure everything is secure, then put the battery charger on 10 or 40, whatever your charger has, and use the Hold setting. If there are no noises, sparks, etc., you’re good! (If anything suspicious happens, turn off charger immediately.) You should see some bubbles and swirling nearly right away. Monitor it for a bit, and you should be able to let it go on its own once set up properly. A good setup is only going to take a few hours to clean most pans that have say, light rust. I usually start any gunky pans off in the Lye bath. See https://castironcookingandrestoration.com//clean-cast-iron-lye/.

FAQ and tips:

  • Is the tank going to attract mosquitoes? No, the larvae cannot grow in the electrolyte solution (washing soda).
  • How often should I change the water? Once the water gets goopy and doesn’t swirl easily, time to change out the solution. Otherwise, just add water as it evaporates. Might want to mark your original water line. No need to add more soda. It stays in concentration.
  • Could I electrocute myself? Not likely, and I haven’t tried the following, but many experts have put their hand in the water while the tank is running and only feel a slight tingle.
  • Why can’t I use an automatic battery charger? This would require that you put a dead battery between the battery and the tank so that the charger does not cycle off. The experts do not recommend it, please buy a manual charger.
  • What about computer power supplies? Due to the nature of the best tank build using stainless plates, you need a more powerful charger with a cooling fan. The experts don’t bother with these smaller power supplies and instead buy a nice manual battery charger with an internal cooling fan, plus it will last longer.
  • Strain out your tank with a pool skimmer or kitchen strainer to keep the water cleaner.
  • Do not use more washing soda than recommended. This can cause your charger to have too heavy of a load and short out.
  • Do not e-tank Aluminum, Brass, Copper, anything plated or coated including tin cans, galvanized sheet metal etc…The things mentioned here should not be in an E-Tank AT ALL in the form of anode or cathode!
  • DO NOT run your tank on the 200 setting, this is only for starting a car!
  • Use a well-ventilated area, preferably outside for your tank, and no smoking around the tank.
  • Once you take your pan out of the tank, be prepared to at least clean it with Dawn soap and get it oiled and ready to season. See https://castironcookingandrestoration.com//seasoning-cast-iron/.
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Seasoning Cast Iron-What Does It mean?

One might hear the phrase “seasoning cast iron” and think, “what do I salt it or something?”

Seasoning is the application of oil to bare cast iron, then going beyond the smoke point of said oil to create a polymerized layer; a protective coating commonly referred to as seasoning.

And old friend of mine might say, “Is this seasoning process really necessary?” I say wholeheartedly yes. A good seasoning creates a non-stick layer to your cookware, makes it easier to cook and clean your cookware, and protects the cast iron from rusting.

So what do we use for seasoning? Really, anything you want. Most professionals I see use Crisco , and I personally prefer it for seasoning. You can use Crisbee Pucks, Canola, Safflower, Avocado oil, lard, beef tallow, and the list goes on. I suggest you Google “oil smoke points” to obtain a chart of smoke points for different oils.

So how to we begin the seasoning process? First, you need a clean piece of bare iron, meaning any previous gunk, or seasoning layers will be removed. First the piece is cleaned in lye, and possibly also through an electrolysis tank to remove rust. Then, clean the piece with Dawn Soap and cold water (hot is okay as long as the piece is not flash rusting), Scotch Brite Stainless, and Mr. Clean Magic Erasers, Extra Durable version. Additionally, you can use stainless steel brushes for tough pieces, or crevices such as waffle irons. I personally do not recommend using any power tools or wire wheeling. Never clean cast iron in a fire. I do not recommend using the self-clean oven method because this method can do damage to both your oven, and the iron by cracking it or causing heat warping, and/or rendering the iron unable to hold a seasoning layer. Once you start cleaning the iron, you’ll need to at least get to the point of putting the oil on the iron, or you’ll need to put the piece back in the tank to prevent rust.

Once the initial dirt comes off, use the magic eraser and some Dawn to go over the piece until no more visible dirt is coming off, and you see greenish tint on your sponge. Then quickly dry the piece with paper towels or shop towels. If you have a gas stovetop, quickly heat the piece just enough to get a layer of Crisco or oil on the piece. I really like the blue shop towels for glass. I recommend oiling the piece before heating if you have an electric stovetop, because you’ll need to heat your pan initially in the oven, and that may be just enough time to start flash rust.

Seasoning in a Gas Oven Vs. Electric

Here’s where it gets tricky. Gas ovens put off moisture, and this can be a problem at lower temperatures, as it can cause the piece to have spotting and rusting in the oven. I recommend starting a gas oven off at around 275F. Once it’s heated, take a heavy towel and wipe any visible moisture off the glass, be careful and use a pot holder. Also, pop the door open periodically to let any excess moisture out. Gas ovens tend to climb in temperature quickly, therefore, a graduated temperature approach is recommended, commonly referred to as the 200/300/400 method, but we’re going to go higher and do 275/375/475-500 at the end.

Also, you’ll heat your piece on the stove-top and apply a liberal layer of Crisco with a pastry brush or paper towel. Let it sit until it cools completely, preheat the oven to 275F in the meantime. Once the piece cools down, you are going to wipe, wipe, wipe all the Crisco off with the blue shop towels until the piece looks dry. Then wipe it a few more times… Place in the 275F oven for 15-20 minutes. Then gradually raise the temperature by putting the dial on 375. Heat for another 20 minutes. Then put the dial to 475 and that’s where you’ll do the pan for about 30-45 minutes. Sometimes I’ll finish off at 500. Let the piece cool down in the oven. Do the process over again for additional coats. I usually do 2-3 coats.

Electric Oven:

You’ll need to oil your piece cold, then heat it in the oven at about 250 for 15 minutes, this will be an additional step. Once you take it out of the oven, you’ll let it cool down. Once it cools down, you are going to wipe, wipe, wipe all the Crisco off with the blue shop towels until the piece looks dry. Then wipe it a few more times…

Start off around 250. Nothing additional needs to be done, as electric ovens heat more slowly and do not produce moisture. Once the pan has heated for about 15 minutes, increase the dial to 450-475 and monitor. Graduated temperature method is optional. Once the oven is up to 475, season the pan for 30-45 minutes. Sometimes I’ll finish off at 500. Let the piece cool down in the oven. Do the process over again for additional coats. I usually do 2-3 coats.

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