1st April 2021 Grr?

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Thursday 1st April. Heavy overcast and much cooler with wind.

Last night, at dusk, I spent over an hour clambering all over the dome with umpteen assorted ladders, moving paving slabs and foam pads. Having the laser mounted high up finally allowed the lines to be seen on "the summit." So I went round [and round] with a pencil and drew over the projected, green, laser lines. 

The main problem was in seeing what I had done. So I repeated the entire exercise using a fine, marker pen. I still could not see the marks in the semi-darkness but continued anyway. So, today, I hope I have an accurate rectangle drawn on the outside of the dome. I shall use this as reference to align an inner "scribing frame" to mark out and cut the dome's observation slit. Without the exterior markings I'd have no reference for the inside work. 

In a moment, I shall see how well I did. I want to follow the moulded "facets" to keep everything aligned and not look horribly askew. Having marks inside and out should help this cause. I still have to mark out the spare roof panel for the shutters. I am still thinking how best to go about that. 

Well, the marker pen went completely unnoticed! Washed away by the overnight rain? Who knows? I could just about make out a few, faint pencil marks. Though I'd need a ladder to see them beyond the first foot above the doorway. Did the marker pen rub out the pencil marks? Then itself vanish overnight? 

I couldn't see, by laser light, whether I was actually doing anything useful last night. It would seem not. Even the central line wandered off the top ridge in the moulding. The central bolt over the doorway was an inch off-centre when I checked with a tape measure.

I decided to use my remaining strength and willpower to cut the cladding plywood to size. The frames varied slightly between 89cm and 88cm in width. So I cut the eight sheets to 90cm and will trim one edge to match the needs of each panel. 

It is hard work lifting full sheets of 12mm ply up onto the saw table. Then pushing them through the table saw. Then carrying the remains away for storage. I used long planks set on edge in B&D folding workbenches for edge support. The roller stands were arranged on the other side to support the off-cut strip.

I managed to trim and fix seven, lower sheets of the eight I bought. It was very windy from the north. So was a struggle controlling the sheets at times. I marked the cross brace positions onto the upright posts. To save searching for them once each sheet was in place. I even used a level to draw lines for extra screw fixings onto the cross braces. 

Placing the eighth sheet in the NE would have denied me access to the fixing screws of the old, octagon cladding. Though I could always remove the new sheet, later on, to get at the screws if needed. There is only a few inches of extra space involved just there. So I could just leave that part of the octagon untouched for extra strength and stability. 

Now I have to gather my strength to fetch another eight sheets of cladding ply. To be fixed "upstairs" as the newly expanded, observatory walls. I already have the Z-profile, aluminium flashing to go between the upper and lower sheets. This introduces a slight problem in that the upper sheets cannot be rested directly on top of the lower. I shall have to fix stop screws to have something on which to rest the upper sheets. With a small gap between the upper and lower sheets to allow for the angular "fall" of the flashing.  

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