Dome build: Top tier panels.

Wednesday: Drove to the builders' merchants for 3 sheets of 12mm birch ply but only available in 5'x5'. Went on making top tier panels. They are all the same base width but with different lengths and angles at the narrow ends.

Thursday: Very wet all day! Tidied the shed so I can have the miter saw ready and out of the rain. I fitted some large, heavy duty, shelf brackets to get stuff up and out of the way. The saw now sits happily underneath.

I realised the other day that my dome could be duplicated with much less effort in aluminium. Using square section for the ribs they need only to be V-notched precisely and bent to the closing angle. A dihedral plate will then be fixed over the inner side of the joint for the horizontal members to be attached.

The dome could then be covered in thin aluminium sheet. Hopefully a local engineer would guillotine the shapes to order from drawings or patterns. Each tier of panels would be identical to each other.

Pop riveting and/or gluing the covering to the skeleton will make the dome incredibly strong yet light. The panels could even be cut as a long tapering strip if there is enough guillotine capacity. They only need a gentle bend to be applied where they meet the joints.

Friday: Quite a pleasant day peaking at 65F.  I trimmed and fitted the first three 15mm birch top panels. They are so pale the dome now looks like a snow capped mountain. I haven't routed the underneath edges to lower their visible profile. They form the backbone of the dome where it joins the slit frame. I'll life with them for now to see if I'm feeling obsessive about it. I have a sheet of 12mm birch ply marked out for a lot more panels but need to confirm their lengths first. No point in wasting materials unnecessarily. I can use the previous panel to measure the edge length of the next.

It has been suggested that I undercut the lower edges of the top tier panels with the table saw. Which sounds like a far better way of doing it than routing. I can even set the saw blade over to achieve an angle to allow the boards to rest flat on top of the next lower tier.

Click on any image for an enlargement.

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