23.08.2021 More thinking aloud.

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Monday 23rd. Misty start to a sunny day. Heavy dew.

I have timed it badly to have no resin left as two warm and sunny days mark the end of summer. So I had better do something useful while it is dry and sunny. Not wait until the grass and everything else is soaking wet.

The base ring needs the ends of the arcs trimmed to make accurate joints. The sliding mitre saw is the best tool for this. I need to lay out the complete ring on the ground. Then mark each joint clearly ready for gluing and laminating.

The shutters are easily accessible now they are lying on the ground. So I can fit the rubber washers under the heads of the bolts to weatherproof them.

I need to cut out and laminate the shutter top boards in readiness for the drawer slides. I finally have suitable brackets to fit them securely to the GRP shutters now. The top, inner brackets need the GRP lifting to fix the screws. Better done now than with the entire weight resting on top of the ribs.

The drawer slides could be fitted to the zenith board. I have a safe and proven support system for the open shutters. Which means I can more easily fit the drawer slides to the shutters once they are back in position. This would be more sensible than fitting the drawer slides to the shutters first. Then fixing them to the zenith board afterwards. 

The alignment of the drawer slides is critical for the shutters to slide properly. I might need to compensate for shutter weight causing some sag or twist. This should be done invisibly inside the top shutter boards. Not by adjusting the level at the zenith board. Which might cause bias in the opening and closing of the shutters. Not to mention looking completely wrong if they are slanting.

09.46 [CET] I started with some imaging while I wait for the heavy dew to disperse. 

10.09 Retuned the PST etalon repeatedly to get it on band across the frame. Only partially successful.

10.52 Now relying on a rubber band to tilt the etalon.

11.03 More fiddling with rubber bands.

 

 

11.09 It is a struggle to balance the entire frame on band.

 

 

 

 

11.18

 

The sun was finally on the dome. So I removed the tarpaulin from the slit and was soaked by dew! There must have been pints pouring off it!

 

 

 

13.00 Paused for lunch having laid out the 4.3m base ring on the ground. It is huge! It seems far larger than the dome itself. 

One tent peg in the middle and a surveyors tape led to more tent pegs. The arcs could then be snuggled up against the pegs as a perimeter. 

Image taken from a stepladder. The poor man's drone. 😉 And a handy, tiered stand for displaying my wife's potted plants.

After lunch I shall put a single screw at each arc overlap. This will provide a reference point for marking out the skewed and staggered joints. The exercise will then be repeated for the second layer.

Joints sawn and lots of stakes hammered into the heart of the dome. The arcs did not want to remain level. So I am waiting until it is darker. Then I will mark all the stakes using the 360° laser level. I'll drill the stakes and push supporting nails through. If I try to drive screws through the stakes they might split.

 

 

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