Dome assembly question

DoctorIknow · Post by **DoctorIknow** » Mon Jul 31, 2006 1:01 am

Thanks to eplaya posts, I suddenly grasped that my 4 frequency dome was actually five sections (28 triangles each) with five other sections "at the bottom" of 4 triangles each.

I've assembled this dome from ground up two times, it sucks, and I can't rely on playa volunteers to build it from the top down (and don't have a sky hook LOL)....

I thought this time I'd make the five (28 triangle) sections on the ground, then set my ladder and have all pieces join at the top and sides. (Bottoms won't touch yet...that's where the small 4 triangle pieces go...)

I will need 30 extra spars to build out the 5 sections (since where the sections join will now have two spars instead of one) and these extra spars will be removed once the five sections are "up" and it should be easy to loosen and tighten just six joints on each side, as everything should be pretty well lined up. Then I'll fill in the small sections (4 triangles) at the bottom. BTW, it's a 30' diameter.

Any problems I haven't thought of?

Here is one section on the ground (The photo looks weird 'cause I outlined the spars):

falk · Post by **falk** » Mon Jul 31, 2006 1:52 pm

I think it's an excellent idea, and definately worth trying out. (Of course, I can also think of a couple ways it could go horribly wrong.)

If you can, do a test assembly at home before the burn. Let us know how it works out. Will the simplicity of setup (plus the fact that 5 teams can work independantly), outweigh the hassle factor of undoing so many bolts and dropping so many struts? I for one am looking forward to finding out.

DoctorIknow · Post by **DoctorIknow** » Tue Aug 08, 2006 5:42 am

I took the section in the picture, staked the "bottom" of that dome section (on the right of the photo) and with a rope, hoisted it up to nearly verticle. I was real excited seeing it standing, until I thought "What if a strong wind came up while it's standing" so I shook it some and it collapsed, slowly and silently.

The stress was just too much for the pounded conduit ends. Heavier conduit (meaning stronger ends) would only add more weight, and those ends are just so inherently weak that this idea is totally dead....

Bucky had it right. Top down construction most logical...

capjbadger · Post by **capjbadger** » Tue Aug 08, 2006 11:39 am

Hell.. yeah, I can see how a section by itself just isn't stable with out the rest of the network to help it out.
I've always said smaller domes you can build bottom-up, but for larger ones (yours looks pretty big) Top-down is the only way to go as long as you build balanced so it doesn't "taco" from the uneven hanging weight.

How tall is it? Can you have it hang on some sort of scaffolding while you build?

DoctorIknow · Post by **DoctorIknow** » Tue Aug 08, 2006 5:15 pm

It's a 30' diameter, and today I bought a scrap sailboat mast, about 35', which I'm going to saw into a 16' usable piece. I've thought of a way to stabilize it from outside the circumferance of the final assembledge, and the mast base will be stable also. I'm getting a gang of pulleys and a long piece of line to hoist it up. Mast even has a huge cleat at its bottom! (haven't figured out if it's going to make it OUT of the dome without some spar disassembly LOL)

Fortunately, I have enough time to do this rube goldberg at home.... I made a promise to myself never to build the dome from ground up again, and don't want the easy way out with a material lifter, which also cost a fortune, even to rent...