Cast Iron Pan Electrolysis Stripping

Our cast iron pans need seasoning, so I decided to start with full-metal-jacket electrolysis stripping, rather than soaking them in oven cleaner / smogging the kitchen with the self-cleaning oven / actually doing any work. The electrolysis setup involves the big battery charger and a bucket of sodium carbonate solution:

Cast iron pan electrolysis - setup

Cast iron pan electrolysis – setup

Although the charger has a 40 A capacity, the small pan bubbles along merrily at a self-limited 7 A:

Cast iron pan electrolysis - bucket

Cast iron pan electrolysis – bucket

The anode is a big sheet of steel that was once an EMI shield in a big PC case. The side facing the pan corroded very quickly, but the outside remains in good shape and I think it’ll suffice for the medium and large pans.

After two hours, only the crustiest bits of the crust remained:

Cast iron pan electrolysis - 2 hours

Cast iron pan electrolysis – 2 hours

Those flakes fell right off after a few pokes from my demolition scraper; definite anticlimax, that.

Another hour in the tank cleaned the handle and removed a few other spots; it now sports a layer of flash rust that’ll require another pass after I strip the other two pans…

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  1. #1 by Hexley Ball on 2016-09-05 - 12:59

    Great info in this post, Ed. Thanks for the tips. I have a hand-me-down cast iron skillet from my late mother-in-law that really needs the full treatment — it has 50 years of crud buildup.

    What oil are you going to use for seasoning?

    • #2 by Ed on 2016-09-05 - 19:42

      Half a century of crust will fill your bucket with a truly disgusting mess. Give it most of the day, scrape the pan occasionally, and it’ll be all good.

      I’m following the flaxseed oil process in the first link, as it seems to have far less woo than most of the nonsense I’ve read over the years. As nearly as I can tell, thoroughly heating the pan before adding the oil just dries it out: “opening the pores” is nonsense. I’m skeptical of forming magnetite in the kitchen, too.

      More later… [grin]

  2. #3 by solaandjin on 2016-09-05 - 23:46

    Holy cow, that’s awesome. I may need to try that. I don’t have a battery charger, but I do have a battery! A jump starter, rather, which is rated for 18 Ah. That should be good for 2+ hours, right?

    Did you do a comparative test vs oven cleaner + trash bag? If I didn’t see this post, that would be my #1 choice, or possibly just set it on a lit pile of charcoal in a grill until it burns out. In fact, as I think on matters, I can’t think of a good sacrificial plate I have on hand, so….

    Currently, all the seasoning on all my cast iron happens to be fine, so this is more a matter of intellectual interest. I agree with you on the high level of pseudo-scientific speculation regarding cast iron and seasoning. The bottom line from my reading would be, “form a layer of polymerized oil.” It’s not hard. Flaxseed oil does seem to have better characteristics for polymerization than other oils.

    • #4 by Ed on 2016-09-06 - 07:40

      I think “jump start” batteries expect to produce a gazillion amps for maybe 10 seconds and can’t handle relatively high current for hours. The pans required half a dozen hours each, so you’re definitely looking at many charge cycles.

      Hosing the pans down with oven cleaner, scraping them, and iterating until clean fills me with dread: that stuff is nasty and I hate getting all dressed up for work. The high-temperature options involve pillars of tell-tale smoke, not to mention maybe warping the pan.

      All in all, electricity seemed the least exciting choice. Anything metallic will serve as the anode, with surface area counting for more than anything else. Sacrifice the lawn furniture!

      Granted, buying a new charger specifically to strip your pans makes no sense. They tend to be $10 items at yard sales around here; ya gotta have stuff, right? [grin]

  1. Cast Iron Pan Seasoning | The Smell of Molten Projects in the Morning
  2. Cast Iron Pan Electrolysis: Anode Fragment | The Smell of Molten Projects in the Morning