15.05.2021 Lift that rib. Tote that glue.

 *

Saturday 15th 50-52F, heavy overcast becoming breezy from the west. The constant overcast and endless bad news are making me depressed.

I erected a central shutter rib again to confirm the required length and depth. The underside of the top of the rib needs to be notched to fit over the top of the dome. Then I need to shorten the lower end of the rib so that it sits on the base ring. Though some clearance will be required so that the shutter can open and close. Supported by the drawer slides.

I am struggling to decide on using 3x8mm ply instead of 2x12mm for the ribs. Both would be equally thick. Three lamination allow more staggered joints. Unless I make a decision soon I can't progress. 

There is no point in trimming the existing rib just to prove that my measurements would work. Not if I will immediately remake it in 3x8mm ply. Though I can re-use the rib as material for the roller, base ring. It just needs to be slightly trimmed to match the dome radius.  

The building can't have a new door unless I move the massive pier. If I move the pier I lose the ability to image the sun. [What sun?] I can't build the cross axis mounting until I have the new dome in place. I wouldn't want to lift it over a towering northern pier! 

It all feels a bit Catch22. When I really should be maximising my efforts in the cool weather. Whenever it is dry, of course. 

Well, I notched the top end of the rib and it slid inwards by the desired 100mm. The notch would only have cost me 100mm or 4" of plywood rib. So I went ahead anyway. It fitted nicely into the mock-up of the extended base ring in front of the doorway. 

It is good to confirm that I haven't completely lost my grip on the simplest geometry. The lower image [left] shows the rib in the centre of the slit cut-out. [Though not trimmed to length] The doorway, support posts are actually upright but the TZ7 camera lens has barrel distortion.

I should go ahead and cut some more ribs in 12mm ply. Then trim them accurately with the router and trammel bar. 

I bought some Gorilla, wood glue for laminating the ribs. Now I find I can't use it at ambient temperatures! The forecast is for it to remain cool [cold!] right through to the end of May. With maximum temperatures down to 4C. I was wearing my scruffy, old, winter down jacket all day today. Bought in a charity shop over 20 years ago and still leaking feathers.

*