Dome build: Shutters: Lifting and fitting the outer ribs.

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Friday: Bright start but risk of showers. Getting the spaced pair of shutter ribs up the ladder was a real struggle. The bottom crossbar kept hooking under the second ladder. Then it all blew sideways as the gusty wind really picked up.

That actually helped because I needed the rib assembly to slide inside the top of the outside ladder. In the end I had to add another crossbar midway. Then lift and re-screw the top crossbar repeatedly to allow the shutter ribs to sink down to the dome surface. Which meant my plywood reinforcing patches were now in the way.

Another crossbar was needed to tie off the ribs to the top of the outside ladder with the ribs tipped well outwards. Just so I could rout the patches away to clear the slit ribs. All the while dangling off assorted ladders with squally, light showers @ 59F passing through.

Stopped for lunch at 2pm with routing to follow. No chance. As soon as I climbed up to the dome it started raining hard. The tarpaulins would not pull up over the dome because they were wet and the friction was too high on the slightly roughened surface. So everything is thoroughly soaked and I needed a complete change of clothes. The temperature has dropped to 56F.

At least the shutter ribs are proving to be about the correct length. With overlap above and below the dome.

Later in the afternoon, under a grey and threatening sky, I completed the routing of the oversized plywood patches. I simply screwed a curved scrap of plywood rib above the required cut and made a groove. Then used a hammer and chisel to break the bond of the remaining 4cm wide strip. Even after only 24 hours the bond was strong. Leaving a thin veneer rather than breaking cleanly back to the glue layer.

I could then adjust the top crossbar so that the ribs draped closely over the dome's angular tiers. It now occurs to me that there is really no need to notch the ribs tightly over the dome. Once they fit against the upstand of the slit's ribs, a seal is achieved.

I had no chance to build the two center ribs because of the weather today. I have to work outside because of their sheer size. If I put up the summer flysheet/awning as a temporary workshop, which I used in the heat wave, the rain would just blow straight under it. It proved very sensitive to wind and sprays moisture everywhere.

Click on any image for an enlargement.

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