After all the design particulars were sorted out and the size and shape and general arrangement of the red, yellow and orange pieces were chosen, we were ready to move forward. Now it would be my job to figure out how to make everything work. My biggest issue would be weight. Each 15 foot sphere had to be less than 5,000 lbs. I made a plan for each sphere to have an internal metal structure that would be 9 foot in diameter. Individual glass pieces would attach to the outer surface and vary between 24″ and 36″ in length. The final sphere would be 9 feet of internal metal framework and then 3 feet on each side of blown glass pieces. This would give me the final dimensions of 15 feet.
The internal sphere would be built like a geodesic dome, with twenty individual triangular, curved panels that would bolt together onsite to create the sphere. The sphere design had come to us through the work of a local engineer named Olaf Pederson. The engineering was worth every penny, instead of attempting a design and hoping it would work, Olaf ran the numbers and proved it. And, as it turned out the design would have withstood an increase in weights by a factor of eight before there was any deflection. Through much trial and error we had determined that each individual panel would hold 100 individual pieces of glass of varying lengths and widths. This would create the fullness on the surface that we were looking for. So each panel was fitted with 100 pins of steel welded in place to hold the glass in position. Again I did the math: 20 Panels x 100 pieces of glass = 2,000 pieces of glass per sphere. Up until this point all of the larger pieces of glass I had made had each weighed upwards of 5 pounds. The metal spheres were weighing in at 800 lbs. That weight plus 2000 pieces of glass weighing 5 lbs each would have left me with a total weight of 10,800 lbs per sphere! This was more than twice as heavy as the limit set by the engineers for the building. Even if I thinned the glass mounted to each sphere by 50% -it would still be too heavy. This was so depressing; I had gotten the job of a lifetime and I couldn’t figure out how to pull it off.
After losing a couple of nights sleep from worry I finally slept a solid eight hours from sheer exhaustion. Waking up I finally felt refreshed and rested and I determined to see what I could do to get the weight of the glass down. Slowly but surely, over the next week or so and after a few hundred pieces of glass I began to make 3 foot long pieces of glass that weighed less than 2 pounds! We kept practicing and they began to look better and better until we had a form I found really pleasing. Now the 2,000 glass pieces and the metal frame came in at a svelte 4,800 lbs! It was truly a great day for me and once again- no sleep! But, this time it was just that I was too excited.
The next day, I began another set of calculations… We needed a total of 6,000 pieces of glass for all three spheres. We would have to cut and weld 15,000 individual pieces of metal for each of the three spheres. Each piece of glass was going to need to be firmly attached to the sphere. I did not like the idea of tying each piece off to the sphere with wire. And, although I felt considerable pressure of time, I believed it would be best to take a moment and come up with an elegant solution. While we moved other areas of the project forward I kept trying new ideas Thomas Edison style. After many prototypes of wire and forms I finally found an elegant solution. I made a little clip that reminds me of a grasshoppers leg. With a loop at each end of an L shape spring that will hold the glass at one end and the sphere at the other while tensioning the glass up into the sphere. Adding a neoprene washer and a protective polyethylene sleeve to each metal pin we greatly reduced any stress on the glass. And with each piece of glass firmly in place on its own designated pin we ensured that the glass at the bottom of the sphere would not bear the weight of the glass at the top of the sphere.
Next we began to puzzle out the different diameters and lengths of glass. It was important to me that at any angle a person would see the glass and not through to the metal sphere. Through trial and error we adjusted a pattern of placing the glass. Because of its shape each of the curved triangular panels has pins that are closer together at the edges and further way as you near the center of the panel. Adjusting the fit using different diameters and lengths of glass we created a layout. Once that was done it was simple work to replicate it over the other panels, creating the uniform appearance I was determined to achieve.
One of the things that helped Acuity in their decision to hire me, an unknown, for this project, was my willingness to do a full scale mock-up sphere for their approval. With all of the above questions settled I started to work on that first sphere. This after all, would be when the project was really secured.