Aluminum Domes

We make aluminum sheet metal dome connectors, machined from standard sheet material.
  This is an example of  a connector plate hub for a 4 frequency icosahedral dome.

Hollow tube struts are used - square, round, or any standard aluminum extrusion.
Also can be used with other profiles such as I beams and H beams. Use inner and/or
  outer connector plate hubs, depending on your dome size and requirements. This example
  uses 1-1/2 inch square tubes with inner and outer plates for maximum strength.

Inner/Outer Connectors
  Round connector plates are formed into a shallow cone, matching angle and strut
  relationships for particular dome type and hub type.
For instance the 4 frequency dome has 4 different hub configurations.

Aluminum 6000 series is best for light weight, low corrosion, high strength, easy to work with, and high-tech appearance.
May be painted with durable coatings for maximum weatherability.
 Test section of the 12 ft sphere:

More details on the 12 ft Geo-Sphere