Definitions first...Geodesic means "the shortest line possible between two points on a sphere or other curved surface".
The Geodesic dome was developed by an American engineer, one Richard Buckminster Fuller. Famously the design boasts a number of unique features: it can be fabricated (somewhere, anywhere) and the entire structure can be placed on the ground and immediately be stable and strong. There are no limits to the size of the structure - no matter how big you make it, it will always be strong enough to support itself and a lot more besides.
Click on the images - right - to see them in more detail. It bears repeating (from elsewhere on this site) that all the seams on this piece and every other piece is created with a 100 W soldering iron . It is the tin/lead alloy of the solder which as it cools from liquid to solid on each side of the glass grips the glass. No more and no less.
Applications of the Geodesic dome have been many and various over the years: It has been used as a simply constructed dwelling to provide cheap and effective shelter, to a protective sphere that contains radar installations on land and sea, to massive exhibition constructions, roofs of stadia etc etc.
This piece was particularly difficult to make. Difficult not just because of the complexity, but as the discrete glass pieces cannot be pulled or tugged in different directions each must be exactly cut to size (see dimensions below). As small alignment errors inevitably creep in it becomes ever more difficult to constrain the errors so that everything else fits as it should. Inevitably there was some run out, but unless you know where to look, it is not obvious !
I should explain that the dome is not simply a lot of of pieces of glass placed together over a semi circular former (rather as Tiffany lamps from the far east are made, where various shapes and colours of glass are randomly put together on a former) but, a true geodesic dome.
There are 105 discrete triangles in the piece and they are of only two different sizes arranged in a very particular way. In this scaled down piece one triangle is of sides 52, 52, 61 mm and used to make 6x pentagons, the other triangle is of sides 62, 62, 61 mm and is used to make 10x hexagons. Since you ask (!!), the trick is to build the hexagons and pentagons (as individual items ) first and to then assemble them in a manner that mitigates run out and error. Approximate diameter of the finished piece is 300 mm.
Once you have "got your eye in" you will see that the top of the dome is a pentagon, to each face of the pentagon is a placed a hexagon, between the hexagons are five more pentagons, then more hexagons and so on....
The base is some old and genuine mahogany. It is a sandwich of two layers running at 90 deg to each other. This will prevent the base distorting. The base was routed out and finished with "brushing french polish" wire wool and wax polish.
Click on the image to the right for more photographs ...