LATE ECLIPSES open thread. Have a party.

Fishy tells me that iron in modern usage is more of an alloy, closer to a steel.

I think the phrase "cold iron" refers more to wrought or cast iron (and only wrought iron, if it's before about 1500 in Europe).

Wrought iron doesn't even exist anymore except in scrap, he says. Cast iron is still manufactured, but is WAY too brittle to be used in car parts. Mostly used for old school frying pans and decorative castings.

The composition of wrought iron is pretty different from modern iron, he is telling me. (I will paste more detail if you're interested, but I don't know if everyone else wants to geek out at quite this level.) :)

I'm interested. :D

I can't answer definitively for why it hurts them *specific* to Seanan's books, but here's what Fishy says about iron in general (edited from IM)...

[13:07] Fishy: Wrought iron is a weird composite of higher and lower levels of carbon.
[13:07] Fishy: Cast iron is very high carbon, 2-3%, which is why it is so brittle.

[13:09] vixyish: I'm just wondering if the wrought or cast iron is pretty far in composition from modern usage.
[13:10] Fishy: Wrought is. It basically does not exist anymore, except in scrap form.
[13:10] Fishy: Hasn't been commercially made since the late 60s
[13:10] Fishy: and even that was a tiny little holdout
[13:10] Fishy: Cast iron is still a modern material
[13:11] vixyish: but is brittle, right?
[13:11] Fishy: Yup
[13:11] Fishy: hence only really used for old school frying pans, that kind of thing.
[13:11] Fishy: Decorative castings.
[13:12] Fishy: Your best bet, metallurgically speaking, to explain why old iron was special was to focus on the composite nature of wrought iron.

[13:13] Fishy: So, you get it from an iron bloom, a smelting process where nothing really quite melts, as that takes some very advanced furnace designs for iron. Instead it just kind of aglomerates into a big spongy mass in the bottom of the furnace.
[13:13] Fishy: With lots of unsmelted slag and unburnt carbon mixed in
[13:13] Fishy: You pull that out and hit it with big hammers while still glowing
[13:13] Fishy: This forced out a lot of the crap and compresses the mass into wrought iron.
[13:13] Fishy: You get a very distinct banding from all the different layers
[13:14] Fishy: It has a grain, basically.
[13:14] Fishy: In modern terms, it is a composite, just like fiberglass or wood.
[13:15] Fishy: You've even seen this layering effect, in like old rusty anchors: http://farm3.static.flickr.com/2644/3854292982_9f82bfe9b1.jpg
[13:15] Fishy: Looks like wood grain!
[13:15] Fishy: Different layers corrode at different rates, resulting in that effect
[13:16] Fishy: Makes the iron stronger in some directions than others. again, just like wood.
[13:16] Fishy: You ask me, faeries and vamps share a common aversion to composite materials.

[13:17] Fishy: Here's a better pic: http://www.faqs.org/photo-dict/photofiles/list/3200/4257rusty_anchor.jpg
[13:17] vixyish: so modern iron is not a composite like that?
[13:18] vixyish: I'm not sure the composite explanation would work or the fae, since they are basically medieval tech level and thus use wood for all sorts of things.
[13:18] Fishy: Nope. That only happened because we couldn't get furnaces hot enough, or when we did because we couldn't control the carbon content, resulting in brittle cast iron.
[13:18] vixyish: and they don't seem to mind furniture in the modern world
[13:18] Fishy: Now we can make homogenous steel of any alloy percentages you care to name in vast, vast quantities.
[13:19] Fishy: Well, it could be something specific to iron composites. High carbon hurts in one way, lower in another, but the combination of the two next to each other is the real problem.
[13:19] Fishy: *handwaves*
[13:19] vixyish: *nodnod*
[13:19] Fishy: Prevents blood clotting, maybe.
[13:19] Fishy: Or acts as a nerve agent.
[13:20] Fishy: Sure, sets up a feedback loop between two different pain receptors.
[13:21] Fishy: Choose any delicate biochemical system that is plot-convenient, really :)

So, there y'go. Some *possible* explanations of why, based on the composite nature of iron.

Would also be consistent with why being in a car with modern alloys in the engine is okay (it's only low-carbon iron) but being in a room banded with *wrought* iron (both high and low carbon) is something they can feel in the air.

And why you still wouldn't want to be a fae mechanic, because maybe *touching* the stuff is worse than just having it near you.

*nod* Makes sense.

Though I'm curious about Danny's Gremlin mechanic.

Thanks!

Well, the mechanic part of that was speculation on my part. It could be that only composite iron (the oldest kind) hurts them at all. A mechanic wouldn't be touching that; they'd be touching modern, low-carbon "iron".

This is all fascinating!

I'm also curious *why* iron things hurt the fae so much.

Historically, it's always been that way, and it probably hasn't been especially researched as to *why* - although we've clearly seen that others have researched how to use it to their advantage (elf-shot, the doors to the prison cell, the cell itself). (Both in the series context, and in the fairy tale context in general.)

From a purely scientific aspect, you can theorize that the magnetic properties of iron are disruptive to the powers of the fae. Perhaps the fae have a component that reacts to magnetic fields (the way birds and other migratory animals are theorized to have), and so iron is disruptive in that regard. It kinda makes me wonder how a fae would react to a large dynamo or other EM-generator.

But, again, short of having actual fae to experiment *with* (not on), there's no way to be certain.

That's pretty much the theory that Pratchett uses in explaining how iron affects his elves.

Which may well be where I got it from.

Steal well.

I have a theory about wrought iron being a symbol of humanity taming nature (without wrought iron, axes and shovels are kind of a bust), while the fae, being more naturey, find that in opposition to their philosophical being on a physical level. Sort of. Like vampires and religious symbols, almost.

There are other things fey aren't "allergic" to, though, that are as much a symbol of humanity taming nature, to my mind.