R. Buckminster Fuller was a visionary born near the end of the nineteenth century. As a man concerned about the world’s shortages, he invented the geodesic dome as a means of enclosing large volumes with a minimum of material.

   I first built this dome in the early seventies for about $50. Since then this structure has served as:

* Tent in various campgrounds

* $200 instant cash when a passing stranger wanted it bad enough.

   A solid object with all its surfaces the same shape and size is called a regular polyhedron. A few examples of regular polyhedrons are shown here:

   

   A geodesic dome is usually created by adding additional faces to a polyhedron. Since the icosahedron comes the closest to being a sphere, it is the one most often used for this purpose.

   Picture a sphere just big enough to surround a polyhedron.  Now stretch the center-point of each line so it touches the sphere, and connect these points with additional straight lines. It is important to note that length of these additional lines will be longer than the others (The darker lines in the dome illustration below represent the shorter lengths). Also notice, that their ends connect six lines, instead of the five-point connections of the original icosahedron.

   We have just created the simplest form of geodesic dome. If we wanted to get more complicated, we could now take the centers of each of these lines and project them to the sphere, and so on. For our dome, however, we’ll keep it simple.

   The frame for this 16'8” diameter dome can be built for about $120 (as of March 2010). Properly covered it can be weather-proof and easy to heat. The cost of the coverings varies widely, but is typically less than the cost of the frame. It breaks down to a bundle of struts a little over 5 feet long with a weight of less than 150 lbs.

   On the interior left, you can see the partition curtain that separates the master bedroom and bathroom from the living-dining area.

    Various sections of the covering could be temporarily removed or installed to optimize the momentary preferences of sun, shade, and ventilation.

   The entire camp loaded nicely into the 6'-long bed of a compact pickup, and you could still see over the load through the rear-view mirror.

   When we would rent a campsite for a week at a time the appointments of this cabin included a self-contained flush toilet, and a bath pan we would use for hot solar-heated baths every afternoon. This of course included the usual kitchen, wood stove space heating, lighting, chairs and hammocks as desired.

   From this cabin-campsite base we would tour an area with all the convenience of a nearby home (using the economy vehicle that carried it).

   The dome frame is made from 3/4" thin-wall conduit. It's 16' 8-1/2" in diameter, about 215 sq.ft. in area, and weighs about 130 lbs. Disassembled, it packs into a bundle of struts about 11" in diameter by a little over 5' long.

   Twenty-six 1/4" X 1-1/2" bolts plus nuts are needed to bolt it together.

   It requires two different strut lengths so I calculated where to cut a 10' piece of conduit so you would get a long one and a short one out of each stick (that is how it came out to 16' 8-1/2" diameter). You need five more long ones than short ones, so for the 65 struts required, you'll need to buy 35 10' sticks.

   Cut each one 63-9/16" from one end, and flatten about 2" on each end of the two resulting pieces. I have found that about a 3-pound hammer and a stump or “biscuit” of wood makes an ideal pounder and anvil for this application.

    MAKE SURE that the flattened ends are in line with each other, rather than twisted into different planes.

   DO NOT use a driveway, concrete floor, or concrete anything else as an anvil. The repeated shock of even this hammer will begin to produce cracks far sooner than you might imagine. If you do happen to have a steel anvil available, make sure it’s in the middle of a wooden table, or otherwise isolated from any concrete slab.

   Use a center-punch to mark a drill position in the center of each flattened area, about ½ inch in from each end. I have found that if you use a wooden backing, and drive the punch hard (almost through the metal) it takes a whole lot less time to drill the holes.

   Drill a 5/32” hole in each end of each piece.

   Bend the ends about 15 degrees in the same direction, so they will be tangent to the same 16’ sphere.

   Coverings for this dome have included various forms of plastic, a parachute, wood, and even cement. One I’ve found surprisingly satisfactory is 6-mil black plastic lightly sprayed on both sides with aluminum paint. The aluminizing radically reduces the heating of the sun on summer days, and helps trap the radiant heat of a camp stove and bodies on a cool mountain morning.

   The method I find most versatile is to divide a covering of plastic or tarp into six pieces – one for the top, and five around the sides. The boundaries of these pieces are outlined by the heavier lines on the sketch below.

   The covering pieces are attached by pulling their edges around the struts indicated by the heavy lines above, and hooking them on #10 x 3/4” sheet metal screws spaced 8” apart. Seven screws per strut, with the middle one centered, work out nicely for these lengths. The screws should be installed in the same plane as the flattened ends.

   Five long struts will need these screws to secure the top cover, and ten short struts with screws will be required to run down the sides.

   The edges of temporary coverings of plastic sheeting may be simply impaled on the heads of the screws. More substantial materials can be fitted with grommets.

   When forming a two-dimensional sheet to a three dimensional surface, you’ll need to take up some slack around the edges. Fold the excess along one of the struts and secure on both sides with duct tape (unless you feel like sewing).

   By overlapping the edges of the coverings as shown below, you can get a pretty good measure of protection from the elements.

  

   In taking another look at the illustration below, notice that five short struts (indicated by the heavier lines) will join at the original points of the icosahedron. The other ends of these struts are joined by four long struts and one other short strut.

                

    may be a hundred different sequences for bolting this thing together, but here are couple suggestions to get you started.

   Besides the struts – some with sheet metal screws preferably – nuts & bolts, it’s nice to have a few tools. Although a pair of 7/16 end wrenches can do this, a ratchet fitted with a 7/16” deep socket is a great help. If you bought carriage bolts instead of hex-head (as I prefer), you’ll need a pair of vice-grips to grasp the heads. Vice-grips are handy anyway, to help adjust errant strut ends, and to compress stacks of them while bolting. You should also have a hammer, something to stand on, and a friend.

5. Once everything is together, walk around the frame a couple of times adjusting the position of each of the ten connections on the ground to relieve stresses and conform to any irregularities.

   As you build it, aim the screws in the five long struts around the top, inward, and the screws on the short struts all towards the right. This will give you consistency and a water-shedding overlap when it comes to applying the covering.

   This structure has quite a bit of volume for its weight, so under windy conditions so you might prefer to tie it down to terrorizing the neighborhood with an exceptionally large tumbleweed.

   One very secure way of doing this is to flatten and drill one end of short (about a foot) pieces of tubing. Dig small holes under the connections on the ground, bolt on the short pieces, and cast them in concrete.

   In one case, I dug a ditch about 6” deep around the perimeter and laid the bottom of the plastic in it. When this “skirt” was covered with dirt, it made a secure, draft-free seal.