Anyone looking to get rid of a dome?

[alt12]

My camp is looking to add another dome to our set-up and we are hoping to procure one from someone who's camp may be disbanding or perhaps are burnt out on the dome thing (I know I am). We've built 2 mediums sized (16ft and 24ft) domes from scratch with the help of the BM community but would really like to have a much larger one for throwing larger parties and hosting DJs. We are looking for anything between 30 and 60 feet. Contact me if interested. We might be able to throw some money your way from our reserve funds.... thanks...
alt

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I don't have a dome to offer, but my camp made a 28' diameter 2v dome out of 1" EMT. 1" EMT is about 4 times as strong as 3/4" EMT. The triangles are pretty big, but it is quick to set up and still very strong. And, with triangles that large, any one of the ones pointing "up" can be your door. 1" conduit sticks cost about $10 each and you'd need 65. So, you're looking at about $650 plus the cost of covering it. That is actually pretty cheap for a dome that large... And with only 65 struts to cut, you can build it in one day if you have tools and a couple people to help.

Building domes is pretty easy. Here are some links:

http://www.desertdomes.com

http://www.timefold.com/dome

http://www.timefold.com/domedeck

Best of luck!

[bburrito]

How sturdy was the 2V dome with the 1" EMT? Is it sturdy enough to hang a hammock from? Sturdy enough for the wind?

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Well, it is actually really, really sturdy! You could hang a hammock from every pair of adjacent vertexes (5 hammocks). You could also hang another 200lbs from the center vertex.

We covered ours in strong canvas and it took all the desert could throw at it two years ago (it was also set up three years ago).

The struts were about 9 feet long -- pretty long. But the 1" EMT is really tough. It is thicker than the 3/4" EMT, and it has a larger diameter. Both of these contribute to its exceptional strength -- over 4 times as strong as the 3/4" EMT.

By the way, the suggestion to build a large 2v came from the person who operates desertdomes.com -- she said it would be easier and cheaper than building an equally large 3v, and would still be plenty strong.

The only "down side" is the very large triangles it forms. We thought they were fine, and they made excellent doors. But, as you know, a 2v is not as close an approximation of a sphere (hemisphere) as a 3v would be. It isn't as "smooth" looking. We didn't care -- we just wanted a big, sturdy dome.

[bburrito]

How were the large triangles in the wind? With such an unsupported area, was there any problem with the covering ripping or anything when the wind blew?

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That is a good question. Yes, because the triangles are large, a lot of force can be applied to them because of the wind. We used very heavy duty tarps made of plasticized canvas (a material called "pyrotone" which used to be used for military tents as it is fire-retardant).

I think that very heavy duty tarps would work, such as the blue/silver tarps sold at Costco in pairs for about $18 a pair. They are extremely durable and are an excellent value -- I own about 20 of them. I think they are 12' by 16' or something like that. They have reinforced grommets. In all my years going to BM with those tarps, they have never torn or failed. The cheapo blue tarps they sell at home depot are worse than worthless! They deteriorate and shed blue fibers all over the playa -- a cleanup nightmare. The grommets tear out and the tarps tear. They simply are not sufficient for the playa.

I've also seen the brown/silver heavy-duty tarps from Lowes that seemed very good and apparently they are not too expensive.

Anyway, yes, you will need to use the best tarps you can find to cover the large triangles.

[capjbadger]

How were the large triangles in the wind? With such an unsupported area, was there any problem with the covering ripping or anything when the wind blew?

You can also tie cords/ropes across each triangle (3 ropes, point to opposite side) to add support for the tarp and prevent it from billowing in and catching wind.

Badger

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I wonder how much that would actually help... You'd end up with more, smaller billowing "cups" to catch the wind, but the same overall area to catch the wind. If I attempted this, I'd attach the ropes to the vertexes, not the middle of the struts. Transferring force to the middle of the struts is not ideal -- that is where they are weakest (they can bend).

If you keep the tarps tight (e.g. use strong bungie cords and bungie balls) then they won't billow much and the wind will mostly slip past.

The worst possible covering would be a parachute... ( http://www.timefold.com/dome -- halfway down the page is my parachute rant )

[capjbadger]

I wonder how much that would actually help... You'd end up with more, smaller billowing "cups" to catch the wind, but the same overall area to catch the wind. If I attempted this, I'd attach the ropes to the vertexes, not the middle of the struts. Transferring force to the middle of the struts is not ideal -- that is where they are weakest (they can bend).

No no... Draw a triangle. Now draw lines from each vertex to the opposite side. It will hold. If it couldn't, it wouldn't be able to hold up in a wind in the first place, ropes or not. I'm well aware were the weak point of a dome is.

Like this:

Black is struts, red is rope.

Building a 2v dome with 9ft struts is pushing things already. You really shouldn't be going much past 5' or 6' in strut length to begin with.

No. You do end up with more "cups", but the actual total "cup" volume is less. 6 one oz cups < 1 one gallon cup.
I've done it. It works.

Badger

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Oh, OK I see what you mean now. Sure, that would be fine. The struts are already bearing that load. But, I wonder if it would be necessary -- we found that as long as the tarps were tight, they didn't billow much at all.

Most people aren't used to how strong the 1" EMT is, so it seems like 9' is long. The 5' to 6' recommendation is most relevant to 3/4" EMT -- not to 1" EMT. The 1" EMT is really very, very strong. You could bend a 6' x 3/4" strut with less force than you could bend a 9' x 1" strut. The 1" EMT is over 4 times stronger according to Tara of desert domes. So, I'm not sure that 9' x 1" is really "pushing things" further than 6' x 3/4" -- I think it is not pushing them as far. Our 28' 2v made of 1" EMT was incredibly strong.

Just for fun, go down to your local Home Depot (or wherever they have EMT) and grab a stick of 3/4" and flex it. Then do the same with the 1". The difference is really startling and enlightening. No need to trust me -- you can feel the difference for yourself.

[capjbadger]

True, a tight tarp takes care of itself for the most part. The extra support is more useful to someone that is using either un-fitted taprs, or large openings.
On the "ideal" 2v dome I have it wouldn't do too much for me.

Oh! 1" EMT. Yes, I was thinking the typical 3/4" stuff. 4 times stronger? Wow... Good to know since I have a new (crazy) dome in the planning stages and it's going to need to be strong.

Now I just need to find a cheap source of 1" stuff. Home Despot is stupid expensive these days. ugg..

Badger