(no subject)

[gfish]

Over the last few weeks I've blown glass. I've welded (gas and stick). I added an outlet in the basement and I've handled hot video lights. I moved flammable liquids galore to the new house. I even biked 102 miles under a unusually bright and hot sun.

So how, exactly, did I get a nice inch long burn on my hand? The worst burn I've had in several years? By reaching into an oven -- a boring, electric kitchen oven -- to remove a pie. I suck.

It was a really yummy pie, at least.

Edit: Nice. Not nine. If it was a nine inch burn I'd be posting pictures or something.

Comments

I'm gonna do it, I swear.

[dannison.livejournal.com]

Just about to leave Mexico, and I don't have enough money to go back to Coyoacan and buy a Mahuaquitl. So I've resigned myself to making one myself.
I've already purchased a significant amount of obsidian through e-bay, so there's no point in trying to talk me out of it.
Essentially, it's a large, flat wooden sword with three inch long pieces of obsidian set lengthwise up the two edges, to create a very sharp "glass" edge.
This requires knapping obsidian.
I know next to nothing about stonecarving, and I need someone to help me figure stuff out.
The obsidian pieces don't need to be pretty, just uniform and roughly the same size.
I've already figured out how I'm going to set them in the wood, that's taken care of. There is nearly no information on the web about knapping obsidian and I'm about at my wit's end. I know it to be extremely dangerous due to the molecule-thick, lung-bound flakes that fly everywhere.
Essentially, I need a list of inexpensive tools that I can use (preferably primitive tools, chisels, that sort of thing.) My wife won't let me spend more that $150 on this little pet-project. If this first one works out well I might do others.
From my experience, banging on solid glass with sharp objects usually doesn't yield the desired results.
Thanks a ton.

Re: I'm gonna do it, I swear.

[gfish.livejournal.com]

The great thing about flintknapping is that all you really need for a tool is a rock. A round river rock would be good. Fairly symetrical, moderately dense and hard. If you want to get fancy you can use a hefty section of antler instead, but not everyone bothers. You'll also want protective gear -- saftey glasses and a leather pad or two. Obsidian really is amazingly sharp, freshly spalled, and small bits can fly out on random trajectories at very high speed. All the equipment you'll need should only cost $30-$50. I'll assume you have a supply of obsidian to work with.

You aren't chiselling the obsidian when you're shaping it. You're hitting it, sending a shockwave through the material which removes a roughly cone-shaped section from the opposite side. Ever seen a little cone missing from a plateglass window, where it was hit by a BB? Same principle.

The concept is simple, the excution takes some practice. The angle you strike at is very important and needs to be fairly precise. There is also a lot fidly constraints on how to prepare a good platform (the bit you're striking) and up what circumstances the spall ends up being decidedly not cone-shaped. You're going to go through several good sized chunks of obsidian just getting the hang of it.

I believe that the blades in maquahuitls were formed with a more advanced punch technique, where you press into the obsidian using a crutch-like device. I've never tried it, so I can't say how hard it is to get right. But I recently saw a cute batleth-style maquahuitl made with the kind of random large flakes you'll get from percusive flaking. Depending on the level of historical accuracy you require, that might be good enough.

There are several good sites on the web for better descriptions of how to do it as well as sources for equipment and materials.