1st August 2021 Prioritize! Shutter Progress!

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A mostly dry, breezy day with some sunshine is promised. What, or where, should I prioritize? Time is passing and temperatures are dropping towards autumn levels. 

Do some solar imaging? The sun is spotless in White Light. Worth it in H-alpha? Gong shows very little of potential interest. Pass.

Or:

Job: The shutter rib levels/heights need immediate attention to straighten the gap between them. I  really need a profile pattern to quickly confirm shutter rib levels. This would save guesswork and pointless "fiddling."

Progress: After much "fiddling" I finally managed this step. The central shutter ribs were simply too high above the dome surface. Not helped by my fitting identical packing pieces between the ribs and tops of the temporary slit cross braces. I removed all the packing pieces and pushed the bottom of the ribs in towards the dome by about an inch [25mm.] 

The central edges of the shutters now fit in a straight line over the central ribs. I had to screw the ribs to the cross braces to stop them moving from side to side. It was a huge relief when the shutters settled down onto the outer ribs. 

I have used multiple ratchet strap to keep the shutter covers tight against the ribs. The shutter covers want to bow out at the bottom. Then slide down due to their flexibility and considerable weight.

I now need to fix the shutters securely to their ribs. I bought a lot of metal brackets in anticipation of this job. However, they will need a rubber washer under the domed bolt heads to stop rain leaking though the holes. Fitting these washers can take place at any time. I shall use the same galvanized bolts as those used to hold the dome together. So they will all match nicely and look as if they are meant to be there. I need to decide on suitable spacing to carry the "rivet" theme over from the earlier bolts. They have the appearance of rivets used on Victorian, wrought iron bridges and other metalwork.

I plan to use fibreglass to bond the ribs to the GRP shutter covers as well. I had no plans to use fibreglass when I started this project. In fact I wanted to avoid it. 

Fibreglass will spread the loads far better than bolted brackets. Not to mention providing greater rigidity and a far better seal against wind and rain. I shall dye the new GRP work green to hide the worst cosmetic issues.

Job: Make more zenith board laminations from 15mm ply. I already have two zenith profiles in 12mm Baltic Birch ply. I can draw around one of these to make more.

Job: Mark out and laminate top board profiles for the shutters from 15mm ply. These hold the drawer slides and close off the tops of the shutters against the weather. These boards are just half the width of the zenith boards and have the same profile.

The open slit would provide easy access and plenty of light only once the shutters are properly mounted on their slides. This will save ducking through the low triangles beside the slit. I am now banging my head on the ribs above the triangles. As I shuffle in while bent over double. The ribs weren't there before. So I keep forgetting to duck even lower.

Job: Order polyester resin and glass matt online.

Job: Start laminating base ring arcs.  These will support the slit ribs at their base. So their height is critical. The red line in this latest, interior view shows the shutters aren't quite long enough. Easily fixed with some extensions cut from spare, GRP dome material.

Job: Tidy the accumulated off-cuts of timber and plywood in the dome. They are useful for quick and strong props for mock-ups but can get in the way. I could use some of them them around the dome skirt for increased support.

Progress: Much tidier now. I can't walk upright near the inner edge of the dome. Because the roof curves over. So I have stacked things neatly in No-man's land.

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