here's a DIY method of making cheap, flexible dome connectors!

when i saw WilliamAAdams' simple tetrahedron http://www.thingiverse.com/thing:8306 it reminded me of the tubing connectors i saw in the great domebook 2 http://www.scribd.com/doc/37419493/Domebook-2

the advantage of a flexible connector is that it doesn't require absolute precision in strut lengths. this makes for easier domeraising and allows the structure to equalize gracefully.

for a similar approach not involving nuts and bolts, see: http://simplydifferently.org/Geodesic_Dome_Notes?page=17

you'll need some vinyl tubing and some nuts, bolts, and washers in addition to dowels or poles cut to the appropriate lengths. these instructions are adapted from WilliamAAdams' excellent documentation.

1) decide on the type of struts you'll be using. we used 3/8" dowels because we had a lot of scrap laying around.
2) get a large quantity of tubing that will snugly fit over the ends of the struts. the dome pictured here required almost 20 feet of tubing.
3) cut the tubing into 2-3" long lengths.
4) drill a hole in the center of each piece of tubing.
5) thread a washer and three lengths of tubing on a bolt, then cap it with another washer and a nut. spread the tubing lengths out to form a hexagonal shape, then tighten the whole assembly.
6) assemble your dome or sphere by sliding the struts into the tubing. whenever a pentagon is needed, simply leave one of the tubes empty.

a 2V icosahedron will require 26 connectors. checkout http://desertdomes.com or http://simplydifferently.org for dome assembly diagrams and strut calculators.