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Fire Damage to Cast Iron Cookware

Fire Damage to Cast Iron Cookware

Fire Damage: What is it?

Sometimes I hear people recommend placing a cast iron piece in a blazing fire to “clean” it. I also hear people recommend cleaning a cast iron piece by running it through the self-cleaning cycle of an oven.

I don’t recommend either method. Both methods can damage your valuable cast iron piece, resulting in warpage, cracking, or both. While the high heat will surely burn off crud on your pan, it may also alter the composition of the metal.

Here is a video I made of an otherwise beautiful Griswold no. 8 cast iron skillet that was damaged by fire. How can I tell? The significant warpage – this pan even spins – and the tell-tale red coloration on the pan. Take a look:

You can see and hear the results of the extreme heat to which this pan was subjected. Once it’s warped, you can’t bring it back. Just say “NO” to cleaning your pan by placing it in a fire!

How hot is too hot?

I don’t know – as I’ve said many times before, I am not a scientist. I do know, however, that a cast iron pan can warp or crack when exposed to very high heat; especially when the heat is suddenly applied. The thermal shock to the pan can cause it to crack. 1

According to information gleaned from the wild and wooly web, cast iron will melt at 2200 degrees Fahrenheit; 1204 degrees Celsius. Another source puts the temperature range at 2060 – 2200 Fahrenheit and 1127 – 1204 Celsius.

A bonfire can reach temperatures as hot as 2,012 degrees Fahrenheit; 1,100 degrees CelsiusA self-cleaning oven can reach temperatures up to 1000 degrees Fahrenheit

Well, now we know how much heat it will take to melt the iron; but how much heat to simply warp the iron? It’s a different question, and I don’t have the answer. If you do, write to me and explain it so that I can supplement this post!

Some folks swear by using the self-cleaning oven and/or fire to clean the crust off of their cast iron pans. Would you want risk damaging a valuable piece of history for the sake of an “easy” clean?

I hope not. Please don’t.

Additional photos of fire damage:

Photo courtesy Joe Zawadowski. Note the dark reddish-orange area; that is tell-tale for fire damage. This pan also has scaling on the surface as a result of the high heat to which it must have been subjected.
Photo courtesy Joe Zawadowski.
Photo courtesy Shelley Moore. This old Wagner pan went through a house fire. You can see the tell-tale red/orange coloration. In this case, the heat was so intense that it actually began to melt the iron.
Photo courtesy Shelley Moore.
  1. For more information on damage to cast iron pans, check out this page.

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