Note: if you're going to do this yourself, consider buying or borrowing real tools instead of the ones we describe below. After helping with another dome-style building project, it's *much* nicer to have a drill press plus jig, an arbor press to flatten, and last but not least a Makita worm drive circular saw with a metal cut-off abrasive disk to cut the pipes. You can see pictures of all of these in action on Howard's Nose-building Party page. I'm making lots of sparks with the Makita about halfway down. See also Howard's Home Dome page for detailed power tools advice.
Bill of Materials
We cut two sizes of struts: the long ones were 76.3 inches, and the short ones were 67.6 inches. (See the Desert Dome Calculator page for how to get these numbers given that we want a 2-frequency 20-foot diameter dome.)
A pipe cutter looks like this:
You just twist the knob until the blade eats all the way through the conduit. There's enough mechanical advantage that it's not too much work to do one pipe.
Some people use PVC or ABS plastic pipe, which is not nearly as strong as the metal 3/4-inch electrical conduit that we chose. I've seen many structures built out of PVC that didn't make it through the storms. Remember, there can be gale-force winds on the playa - that's 70+ miles per hour. The mental image to keep in mind: how well would your structure fare if you strapped it to the top of a van and drove it around a highway for a few hours?
In our early experiments we tried using 1/2-inch conduit, but found that the struts were much too bendable. Our struts can't support the weight of a human hanging from the middle, but the vertices can. (And we do in fact use some of the lower vertices as hammock tie points.) If we had wanted a climbing dome instead of a living dome, we would have had to use real steel pipe, which is stronger, heavier, and more difficult to cut than electrical conduit.
We tried flattening the ends of the conduit with a heavy-duty vise, but it took much more time: several minutes instead of 30 seconds. Also, the vise mechanism clearly would not have stood up to doing all the pipes. In this case, the mechanical advantage of the long sledgehammer handle outweighed that of the vise screws.
We bent straight 3-foot pieces of rebar into giant U-shaped staples. In 1999 we went overboard, and used two staples per strut. Getting them out took forever.
In 2000 we started with only four staples total. This was underkill, and we were afraid the dome would fly away during the first windstorm. We ended up pounding in four more staples with a small hammer during the storm, since our sledgehammer was broken by then. (Before Burning Man, I had no idea that it was even *possible* to use up a sledgehammer!) This was not a win either. I think one staple per vertex is probably a good compromise.
I'm also not convinced that the full U shape is the way to go, since hammering on the bend of the U often just flattens the bend instead of driving the shafts into the ground. Other people swear by candy canes, I'm pondering whether to try that next year.