Geodesic sphere

[Michael]

Has anyone made a geodesic sphere? I am considering making one and wondered if it was as easy as making two geodesic domes with one atop the other? 

Would I need to consider doubling the size of the struts or is there more to it than that? 

[Charles Lasater]

I made a 30 ft dia sphere with 2x4s and 3/4" hubs. After 5 years lower hubs deformed. 

On Mon, May 5, 2025 at 2:43 PM Michael <flood...@gmail.com> wrote:

Has anyone made a geodesic sphere? I am considering making one and wondered if it was as easy as making two geodesic domes with one atop the other? 

Would I need to consider doubling the size of the struts or is there more to it than that? 

--
--
You received this message because you are subscribed to the "Geodesic Help" Google Group
--
To unsubscribe from this group, send email to GeodesicHelp...@googlegroups.com
--
To post to this group, send email to geodes...@googlegroups.com
--
For more options, visit http://groups.google.com/group/geodesichelp?hl=en

---
You received this message because you are subscribed to the Google Groups "Geodesic Help Group" group.
To unsubscribe from this group and stop receiving emails from it, send an email to geodesichelp...@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/geodesichelp/f274c141-73cc-4e8d-8a79-f74a35526a7en%40googlegroups.com.

[Levente Likhanecz]

those deformed hub plates are plywood? 

To view this discussion visit https://groups.google.com/d/msgid/geodesichelp/CADgTqM4WGKTAhvgUDH03xCJahU0sARGGX%3DCr_As1BuhdMRxaJA%40mail.gmail.com.

[Paul Kranz]

Michael: What might be fun is to dig a hole and roll your geodesic sphere into it and then cover up the hole.

Paul sends...

[Levente Likhanecz]

someone made this video. they may have questions. the boy was quite excited to visit your site.

https://youtu.be/rnglBgFZ3hs

On Tue, May 6, 2025 at 12:54 AM Charles Lasater <charles...@gmail.com> wrote:

To view this discussion visit https://groups.google.com/d/msgid/geodesichelp/CADgTqM4WGKTAhvgUDH03xCJahU0sARGGX%3DCr_As1BuhdMRxaJA%40mail.gmail.com.

[Levente Likhanecz]

ohhh, i found it:

https://www.google.com/maps/@40.4989738,-122.3342584,3a,75y,268.61h,89.54t/data=!3m7!1e1!3m5!1sS18UrQB898o0dBZcN2qBSQ!2e0!6shttps:%2F%2Fstreetviewpixels-pa.googleapis.com%2Fv1%2Fthumbnail%3Fcb_client%3Dmaps_sv.tactile%26w%3D900%26h%3D600%26pitch%3D0.45952989441818204%26panoid%3DS18UrQB898o0dBZcN2qBSQ%26yaw%3D268.60504422720123!7i16384!8i8192?entry=ttu&g_ep=EgoyMDI1MDQzMC4xIKXMDSoASAFQAw%3D%3D

[Dx G]

Charles,

 It looked like the struts connected to the hubs at individual points, perhaps at points being those of a pent or hexagon, if connected by drawn lines.  Do the struts actually join anywhere inside the hub?  If they had, do you think the deformation would have still occurred, or was it more likely a softening of the hub material upon weathering?  It seems to me that struts connecting at a single point, like one sees in domes with flattened end conduit, would not be as prone to deform unless they were overcome by weight.  Just wondered if you had thoughts on this anything post-mortem.

Michael - many famous domes are spheres, with some of the larger ones being one sphere enclosed by a larger one, with struts connecting both spheres to each other. 

 thx

Dx G

[Charles Lasater]

The sphere is a double Darwin Dome.  Home | Darwin Domes

Robert Lassiter's answer to D.I.Y. domes.

--

--
You received this message because you are subscribed to the "Geodesic Help" Google Group
--
To unsubscribe from this group, send email to GeodesicHelp...@googlegroups.com
--
To post to this group, send email to geodes...@googlegroups.com
--
For more options, visit http://groups.google.com/group/geodesichelp?hl=en

---
You received this message because you are subscribed to the Google Groups "Geodesic Help Group" group.
To unsubscribe from this group and stop receiving emails from it, send an email to geodesichelp...@googlegroups.com.

To view this discussion visit https://groups.google.com/d/msgid/geodesichelp/f2360d5e-693f-4471-9fc3-bee40bff2457n%40googlegroups.com.

[Dx G]

Charles -

 Very nice dome.  However, a few technical fine-points.  As far as hub deformation - the hub areas, where struts connect, are 2 points per panel. So with a total of 4 points per panel, one could say that the panels are trapezoids with a very small top, being those two point inside the hub very close together. Unlike a true 3 point triangle, this does leave some room for movement, and deformation, even if the materials are stable.  In order for a triangle panel to move to the same degree, it would require bending, stretching, etc. or some deformation of the material itself. 

Actually, in mechanical engineering a lot is discussed about "4-bar linkages" that is quite preoccupied with how a trapezoid of sorts can move.

  So any thoughts on what actually led to the deformation of the dome at the park?

thx 

Dx G

[Robert Clark]

I think over 5 years, the weather just seeped in and the parts got mushy.