progress

the bamboo
The bamboo has arrived! On Monday, I unloaded my bamboo shipment from a large shipping container at Andy Royer's warehouse space on Harbor Island. The poles are now resting in my carport awaiting the arrival of the weekend when they'll be unwrapped and welcomed to the Pacific Northwest with a little ceremony. Then I'll start building!

structural experiments
On Saturday I experimented with a couple of connection ideas - both were somewhat of a failure but not without benefit. The first idea was to use 1" flat nylon webbing straps with ladderlocks to connect the vertical sections with the horizontal frames. The webbing is extremely strong but the ladderlocks were not up to the test. It was annoyingly easy to break the plastic connectors when they were cinched down tight enough to do their job. Dang! So instead of webbing straps I'll use 1/2" black poly rope with a trucker's hitch to cinch it down. I've used that rope on the Playa for a couple of years and it's never let me down.

The second experiment was with the cross sections that bow the verticals. I was unhappy with the double curve that was generated when two poles were lashed to one another at their crossing point. I thought I could brace them with a short length of bamboo that would allow the gentle curve from their compression to remain. It probably would have worked but I never got that far. As I removed the cross sections to reorient them I discovered an inherent instability in the structure: if the vertical sections are not restrained at their mid-point where the cross sections connect, the entire structure is free to twist and loses all its rigidity! Fortunately the problem is easy to overcome by first lashing the verticals together where they cross at the midpoint and placing the cross sections at the end of the assembly process.

I've dis-assembled the mock-up in anticipation of some new building this weekend.

basic geometry
So all this got me thinking about the viability of using a four sided geometry for this tower. It's much more difficult to create a rigid structure from this geometry and it relies on many more connection points than a three sided structure, which by its nature is already triangulated. I've decided to build a couple of sections of the three sided version and see how it looks. It should have no problem reaching the same height as the four sided geometry and will certainly be more structurally efficient - I'm hoping it will be just as beautiful!

lights
I'm planning to light the project with LED string lights and I've been searching the web for a few months looking for a good supplier. Prices vary wildly on these lights, anywhere from $8 to $30 for the exact same product! For the last few weeks I've been trading email with a company that looked like a promising source. They were very helpful in supplying me with information on power consumption and brightness levels for the different lenses configurations. Apparently the smaller the lens cover the brighter the light. I'll be using strings of 70 LEDs at a 4" spacing with a G12 lens (the G12 lens is a 1/2" round shape). On Monday I placed the order for 62 of these strings - the majority of them green. About an hour later I received an email explaining that after actually looking at their inventory, they realized they don't have any green and won't until after summer. Shit! Off to search the Internet again. The company who manufactures these lights had a long list of dealers, many with websites that I began wading through in search of inventory and a good price. Most were out of green. That evening I sent out a few emails requesting quotes from the most promising vendors and was pleasantly surprised by the quick response I received the following morning. I found someone with all the lights I needed for about 30 percent less than I would have payed the first company. Hooray! The lights are ordered and should arrive by this weekend.

shade cloth
I'm considering using knitted shade cloth instead of Aluminet on the base shade structure. I don't have access to a large industrial sewing machine that would allow me to bind the edges of the Aluminet and I'm a little worried about the the edges on the diagonally cut portions. The knitted shade cloth will not unravel and has the additional benefit of coming in different colors. I'm thinking of using a combination of black, tan and white. I may also incorporate some of the white shade cloth in the tower and top in hopes that it will give the tower a little more presence during the day and catch the light from the LEDs in the evening.