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October 2008
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corvi [userpic]
Dali Dreams of Butterflies, II

By request, smelting pictures. These are not from the recent smelting party, where I was too busy playing host, but I am pleased to announce we actually got copper (in usable forms) from the recent one.

We went out to Spokane to build a furnace. I'm only posting this picture because I love the area, love the way the scent of sage gets into your hair and everything you touch, basalt crystallized into six-sided columns, stars bright and clear and true as the ring of an anvil, and the way the heat pulls against your skin. The ground is written differently there, the marks of fire and flood and ice, cryoturbation and erosion and metamorphosis.

How to build a furnace:

First, dig a hole.

You want rocks to line the hole with. Ideally, they should be rocks that don't melt, crack, shatter, or metamorphose in the heat. Let me know if you turn up any; I've had no such luck. We used a landscaping rock called 'Montana Red,' which appears to be landscaper-speak for 'kind of reddish sandstone'. We broke it into large sheets and lined the pit with it.

The rock had sheets of mica in it, which was a neat effect. The mica has different thermal properties than the sandstone, and glowed more brightly, so that when the rocks were in the pit and the furnace was burning, you could see the sheets of mica laid through them like a shining skeleton.

You need some refectory. This is insulation; it reflects heat back into the furnace. Certain types of clays are traditional, but we used powdered basalt left over from digging a well. It was a bit glassy and holographic; if you leaned over so your shadow fell on the pile of basalt dust, you got the distinct impression your shadow was in the wrong place by a few centimeters.

The furnace right after ignition. Actual charcoal (as opposed to processed and chemically-enhanced briquettes) is hard to find, so we ended up purchasing gourmet mesquite charcoal, scented sharp and smoky. At one point, I spilled soda across the stones, and it carmelized instantly, cracklesharp and sweet-smelling, like creme brulee. There was also a sharp subtle hot-metal scent, familiar to anyone who's worked in a machine shop. I would not have predicted that smelting would smell so wonderful.

Ore mixed with iron oxide for flux. The general idea here is that the iron is supposed to combine with the silica in the copper ore to make a compound with a much lower melting point. We mixed it with our hands, and then wandered around being red-handed zombies for a while. They we tried to wash it off. Then we resigned ourselves to being red-handed zombies for the rest of the day. I think I finally got the last of the ochre off my hands nearly a week later.

It makes very good cave paintings, though. :) I hope future archeologists wonder why there's a cave painting of an armadillo in a tophat in Eastern Washington.

This was a reducing fire - that is, we worked very hard not to let extra oxygen into the pit to steal our copper away into copper oxide. Using charcoal instead of wood helps, since charcoal is pure carbon and grabs any extra oxygen that happens to wander into its territory for carbon dioxide. Covering the pit also helps. A strange thing about the reducing fire is that the sparks did not come out of the fire itself, they appeared suddenly about a foot above it where they could get oxygen. From a distance, it looked like the fire was hovering ghostly over the ground with no apparent fuel source.

Making marshmellows over a furnace is a moral obligation. Luckily, we are all good, upright, ethical citizens. Note some cave painting in the background.

All magic is fire, I wrote once in a story I was too embarrassed to post. :) But everything we touch has a hidden color that only fire can find, a light that cannot be seen without unmaking. I wish I was good enough with a camera to show all the little rivulets and puddles of color in smeltfire - dyes from paper used as kindling, blue and red, and little tongues of copper-green like snakescales, edged in gold, and a strange pale yellow like sunset through water.

That was a lot of heat. The red-brown rocks cracked crosswise into thin layers, translucent and pale as paper, laid into unbound books the shape of a hole in the ground. They were strange colors, blue grey purple white, and crumbled into knife-edged shards as we were digging at them, so thin you could see the heat of your fingertips through them.

Glass we made, too, in bubbles and bumps, mostly jet black, but shot with gold and green and copper, and heavier than glass should be.

The strangest things were the dream-butterflies, thin sheets of translucent white marble, sketched in copper and greengold glass by vapor deposition, stuck askew in pairs and chains and jagged DNA-spirals by shimmering black. Fragile and impossible, like three-dimensional calligraphy, or the weight of flight.

Dissected butterfly wings, marble and copper and greengold glass.


Wowowow! Super neat!

Next, pictures from the one that produced copper?

Unfortunately, I don't have pictures from that one! It was at a smelting/forging party, and I spent most of my time instructing people in blacksmithing at the forge, rather than tending the furnace. Most of my pictures are of people who wanted documentation of themselves hammering on glowing metal.

We'll probably throw another forging/smelting party soon, though - it was a success in every way imaginable.

huh; the red ochre looks just like the raspberries i had with my shortcake the other day.

thanks for the pics!

That is completely awesome and I'm sorry I missed it. Do let me know if/when you do it again.

neat! the glazed copper is particularly cool.

as to rocks that can take the heat, what about firebrick? or does it not take that much heat?

Thank you!

There are several kinds of firebrick. They can be insulative, suitably high melting point, or appropriate to the chalcolithic period, any two. :) But yeah, we're thinking of building an aboveground firebrick furnace next time, and thickly coating the whole thing in clay for insulation.

Wow - the dissected butterfly wings look beautiful - what scale are they? Would they survive becoming jewelry and the wear that entails?

Spokane - I had never seen a picture of the area, thank you. It seems much drier and related to the west than the green drizzly image I have of Seattle.

Glad to hear you had a lot of fun - sounds like a wonderful time! How were the marshmallows?

The Cascade Mountains run up through Oregon and Washington. The ocean side of them is green and wet, with mild, rainy winters (no snow), and, uh, mild rainy springs and falls and summers too. :) But the rain can't get over the mountains, and the East side is dry as dust. There are deserts where nothing at all grows (one area near Ellensburg is frequently referred to as 'the moonscape'), but most of it is like the picture, scrub and sage. They get buried under feet of snow in winter, too. It's lovely, but very different than Seattle/Portland/Hoh Rain Forest/etc.

The butterfly wings are about an inch long, I think. I imagine the redpale copper would become verdigris green over time, and they're kind of sharp edged, so I don't know how well they'd work for jewelry.