As a metals guy, I get a little irrational over the way that metals are used in movies. Case in point: Disney’s October Sky. Based on the true story of a West Virginia coal miner’s kid named Homer H. Hickam Jr. who is inspired by the launch of Sputnik 1 in October, 1957, to get into rocketry. He and his friends overcome all sorts of challenge and personal tragedies, build a rocket, and Homer even winds up becoming a NASA engineer. A pretty solid movie overall despite Laura Dern’s… interesting… attempt at a West Virginia accent.
But what I can’t handle is this exchange where Homer, his friends, and an instructor are discussing what to use to build the rocket’s exhaust nozzle:
Mr. Bolden: Son, you can call it whatever you wanna call it…but you’re gonna have to have a better steel that can take the heat. Now, I’d say S.A.E. 1018 bar stock ought to do you fine, and I can order it for you.
Homer: Well, that’d be great, Mr. Bolden.
Mr. Bolden: But it’s kind of expensive.
Okay, so I respect all metals, they all have their purposes. But, to hold up 1018 as an expensive high-end engineering steel is just pushing things too far. Seriously, it looks like they were using a 6″ long piece of 3″ Round 1018 Bar.
If only there was a place where we could check and see how much that costs! Oh, wait, you can right here! Looks like, at the time of this writing, a 6″ piece runs $34.67 plus shipping. If you figure that prices have gone up 15 times since the late-1950s in which October Sky was set, you’re talking about $2.50 worth of metal, or roughly a half a tank of gas at that time. Sure, that’s expensive for some kids growing up in a West Virginia coal town, but hardly bank-breaking.
But back to 1018. Nice try, October Sky. As a steel, it is pretty good for general-purpose uses, but probably not the best for a rocket exhaust nozzle. You want stuff that can deal with heat, like one of the higher end alloy steels such as 4130 or 8620. If you really want to do it right, get your hands on some stainless, which is the most commercially available high temperature material.
Now you can build better rockets, and be annoyed by trivial bits of metal dialogue like I am.