October 1st: Dome build continued.

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Monday: I'm going around sorting out the bolts and hinges on the doors. Replacing the protruding, sharp wood screws with M5 nuts and bolts. I also stretched and stapled the clear tarpaulin to the shutter doors individually.

The spring clamps were causing puddles, working loose or flying off in the wind. If I rotated the dome the shutter ribs would strike the outside ladder. Which could stop it rotating or cause the clamp to fly off. Now the ladder is adjusted for clearance and the shutters bereft of protruding, spring clamps.

I had the idea of buying some clear polycarbonate for the dome skirt. That would allow some uniform light in while blocking rain and wind. I would also be able to see if anyone was calling without having to go down to confirm it. Plywood and rubber would both be heavier than polycarbonate and both block the light and view below. All three materials have their pros and cons. Polycarbonate is expensive!

This afternoon I should continue widening out the gaps between some of the the trapezium panels. There just wasn't enough room for a good bead of sealer on some seams. Another hour and a half were spent beveling and widening the gaps between panels. Two more cartridges of Sikaflex 591 marine sealant are in the post. I have also ordered two more packets of Safe-Way wood treatment.

Two ratchet straps are now being used to guy the cantilevered ladder to the horizontal, bracing ladder. It wasn't a dangerous setup without them. The ladder just felt more wobbly, the higher I climbed.

I prefer to be able to rotate the dome under me as I work my way all over the outer surface. Having to come down and reset the ladder, just to move the dome, would be a bore and slow me right down. I had planned to extend the ladder with a 4-fold one but it won't bend into an arc without modification to the central, locking hinge. So there is now no point in having a post sticking out of the top of the dome to support such a ladder. I can access the very top of the dome from the open slit when the shutters are opened.

Tuesday: The rain is sheeting down and it is blowing hard but the observatory floor is dry except cfor directly under the slit. I had forgotten to clamp the shutters together so there was an open gap in places. When the shutters are covered an overlap should end this local leakage.The inside of the dome is certainly wet in places but it hasn't dripped onto the floor. Merely [?] run down the inside from panel to panel. Having opened out many of the gaps between panels yesterday this is quite a surprise. I had imagined a flood. The sealant should be delivered this morning but it will be a day or three before the dome is dry enough again to apply more sealant.

Checking Danish suppliers online proved that having polycarbonate cut to a suitable size for the skirt would be ridiculously expensive. Well over £200 equivalent just for a row about two feet wide and a foot deep to go right around the dome skirt. So much for ambient light and an earlier view of callers. I need to progress with the widened skirt to put an end the rain being blown under the skirt. Not to mention the eye-level, eye watering gale through the midriff gap!

I made a pattern of the skirt flashing and a second example to check the length and angles. Then marked the other lengths of flashing ready for cutting. It is not difficult to cut with the tin snips but needs care on the bends. Very heavy showers put an end to today's efforts. The sealer has arrived.

Click on any image for an enlargement.

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