Thursday, December 24, 2009

Understanding Cast Iron

Understanding Cast Iron -The Pots and Pans that last lifetimes

When iron ore has been smelted in a furnace, the initial product is called pig iron. It can be further refined for wrought iron or steel, or it can be cast to make cast iron dutch ovens, skillets, vats, so on and so forth.

I took a tour of a cast iron factory in Tennessee quite a few years ago. The raw iron is melted in a furnace at a temperature ranging from 2800-3000 degrees. The iron glows a yellowish orange when it is hot, the pig iron then flows from the furnace into vats made of steel and then cast in molds made of sand. When the cast iron has cooled, they chip away the sand and recycle it for use in future molds. During this process a lot of sand fuses together with the casted iron. It is sent to a blasting machine, which blasts the casted iron with a steel blast.

The sand molds explain why cast iron has the rough feel to it. The pots are then sent to be inspected then grinded by a worker to insure that there are no sharp edges to the product and if so, he grinds them off. Then it goes into some kind of bath (I don't recall what chemical composition was in the bath) that takes away the sandpapery roughness and leaves a smooth grain. In the final step they take the cast iron tool and it is dipped in wax to prevent rusting and then "you're outta here!!!!!" chungachungabam!!! Cast iron cookery.

Being that cast iron is a relatively porous metal, unlike that of steel, it is difficult to forge, has no real strength, and is the reason why they are so brittle and so damn heavy. For example a 12 inch skillet weighs 7 lbs. while an 8 quart dutch oven with lid weighs 16!!!! Some heavy stuff. Definitely nothing you want to carry in your backpack.

Some disadvantages to cast iron are:
* They are really heavy!!!
* They are brittle. If heated too fast the vessel can crack or split. Usually this is caused by heating the cast iron too rapidly. I recommend that if using a dutch oven or a larger piece of cast iron to fill it with a some water, lard or some kind of fat when you first put it on your fire.
* Cracking is not usually a problem with the smaller vessels, but safe is better than sorry.
* If properly cared for, cast iron will outlast us and perhaps our namesake.

1 comment:

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