Dome fabric question

[Roark]

We have decided to make a pair of domes for the Playa and our other yuppie-scum camping adventures. The first "test" dome will be 20 feet in diameter, and will let me make my mistakes on a small scale. The second will be 30 feet diameter. Both are the L3 variant of Bucky's 4V (250 struts). The 20 foot will be made from 3/4 inch EMT. The 30 foot I have not done a stress analysis on Yet and dont know what I will be using.

My question is this: what cover fabric is everyone else using? My requirements are:
1). Waterproof
2). Medium stretch
3). White or gloss white
4). Less than $15/yard
5). Prefer low breathability (but not vapor-tight)
6). Looks count.

Comments? Thoughts?

This weekend will be the start of my cut/squish/drill festival, with initial assembly test as soon as the weather permits. We want to take the 20 foot to Flipside in May so I really have to hustle... hence my query as to fabrics.

[trilobyte]

3/4 inch seems thin for a dome that size. My dome experience is limited, I've only directly worked with canvas and tarp panel covers. I'd recommend a heavy duty canvas cover. Single cover, not panels. Very expensive, but worth the cost for the strength, durability, and peace of mind. Speaking of peace of mind, you may want to reconsider your conduit and go with 1 inch to 1 1/4 inch.

[Roark]

Thanks for the thoughts, Trilobyte. It's muchly appreciated, especially from a seasoned Burner.

If this was a 1V, 2V or 3V dome I think you're dead-on with regards to the conduit size. The lower frequency domes have long strut lengths and are very marginal (at best) at 3/4 inch. (I can't imagine being in a 70 mph wind in 3/4-inch based 1V/2V!)

The dome I am building is a 4V variant, which means at a 20 foot diameter the longest strut is less than 3-1/2 feet. There are *250* of these critters, so the degree of triangulation is huge. The math says it not only works... it's climbable... and has a hefty reserve factor even in a 70 mph wind. But the 30-foot dome may indeed need to be considerably heavier stuff. (I need to sit-down and model that critter. My lack of data on this is starting to bug me).

On the fabric aspect, I had been thinking about canvas, specifically treated duck. I will order some samples of 10oz and 16 oz treated duck so I can do the touchy-feely thing. If I use this stuff the cover will weigh nearly as much as the structure itself.

I agree with you completely as to making a shell that isn't layered. I have seen video of the results of trying this approach. One edge caught by the wind and the structure will inflate and become a kite. (Might be fun to watch, but once they figure-out whose dome it was, I don't want to be the subject of a lynch-mob!). We would sew the dome cover into two halves on the 20 foot, 4-halves on the 30-foot, with the sides lacing together corset-style and using elastic cord as the lacing. The "seams" would get covered-over with an integral flap with velcro to hold it tight and keep any loose edges from catching the breeze.

Thanks again for your thoughts!

[MrBeardy]

I'll probably get some disagreement here, but for the last few years I have covered my dome with a spinaker sail that I scored on craigslist for free. it is waterproof and while it doesn't fit perfect over the dome, I have perfected it last year with tarp clips to get a solid form fit. I attach it to the dome with grip clips and rope and it has held up just fine. The most crucial thing is rebar. I have yet to have issues with the wind and I think the 3foot rebar I use, while overboard, let's me rest assured when I am deep playa and see a storm approaching my camp's neck of the woods. As for temps inside, it can get toasty during the day but I have rigged it so i can lift up the sides for airflow, and generally I dont hang at camp during the day anyways , so it is nice to come back to in the cool evenings. My buddy wants to build a swamp cooler for it this year, but frankly I don't think it is worth the effort that could otherwise be used for something more fun and interactive for the community. if you have dome questions, let me know. happy to help out! Dome sweet dome!

[some seeing eye]

I have friends who have had covers fabricated overseas in vinyl. Not breathable, heavy, waterproof. It was white, so some heat gain, it needed a top vent. 24' 3V 5/8 = 500 pound cover. I also have some friends who fabricate them in Dacron sail cloth. Water resistant, good color selection. Some people have been printing on their dome covers before they are sewn, don't know the details.

[MrBeardy]

Went solo last year and only covered the top half and made a loft with an old trampoline and wood sheets to create a flat bed spot. Definitley nice to have shelter and a shade structure in one.

[theCryptofishist]

And what will you be cooking in your oven?

[Roark]

young, nubile virgins.

Seriously however, the idea is to roll the sides downs, cover the top-hole, and use an evaporative cooler during the heat of the day.

I build infrastructure like a demon. There isn't a climatic condition on Earth that cant be tamed given enough motivation, energy, and will. Heck, we now have a full-time presence at the South Pole.

BTW: You're invited if we get this puppy running. Did I mention we're bringing a full-sized, hard-sided, stand-up shower? HEHEHEH

[Sunbeam56]

I will be cooking salmon, steak, cornish hens, and other delectables.
Wanna come?

[theCryptofishist]

I don't think I'll be able to get into your dome. And I hate showers on the playa.

[Roark]

Well Darlin, you have a standing invitation and the doorway is wide.

I'd be offended if you didn't stop by for a drink! Or two. Or dinner....

You sorta get the idea we love you? Yes? GOOD!!!

[theCryptofishist]

... the doorway is wide.

It's been a while since I measured but I think it's 24 for paint scraping and 26 for little-chance-of-"bang!". Maybe 3.5' high... Triangles wont work.

[Roark]

HA!. YOu're out of excuses!!! Doorway is 42 inches at the narrowest.

You are SO going to have breakfast and brewskis... unless of course the thought to hanging with a Nerdian Wunderkin and a few Legal-Beagle Goddesses churns yer stomach!

How many days to BM 2013 again?

[EspressoDude]

Plan on staking your dome to the ground. A few years back a wind came up real early during BM (Sunday?) and a dome along the esplanade was not finished, partially covered when the wind came up. It had to be crushed with a nearby high lift fork lift to keep from causing danger blowing away. Wind loads can be extreme.

[junglesmacks]

Green surplus Army parachute for the top and Tyvek wrap for the spaces down low.

[gibson_]

We used black out shade and it worked really well.

We tried tyvek, which was a BITCH to work with, was expensive, etc.

Black-out drapes were cheap, available locally, and easy to work with.

[cahlm]

I used Tyvek in 2008 and 2009, it held up great. Cut it into 6 or 8 pieces (can't remember) and taped it all together with the Tyvek tape. I still have the pieces from those years too, ready to put back on.

[Sunbeam56]

Had lunch today with a guy who rents tents for a living. He had a lot of input that I'm still churning through. Most of his tents are super canvas, some with sunshade built into the canvas. Of course, his tents have to be really tough to be rented out multiple times.

Shade is one concern.
Rain, it does rain in the desert every so often, is another concern. Canvas doesn't really waterproof a tent, it makes most of it run off, and vaporizes the stuff that makes it through.

Has anyone been in a tent in a desert rainstorm?
What kind of cover?
How did it do?

[ygmir]

Thanks for the thoughts, Trilobyte. It's muchly appreciated, especially from a seasoned Burner.

If this was a 1V, 2V or 3V dome I think you're dead-on with regards to the conduit size. The lower frequency domes have long strut lengths and are very marginal (at best) at 3/4 inch. (I can't imagine being in a 70 mph wind in 3/4-inch based 1V/2V!)

The dome I am building is a 4V variant, which means at a 20 foot diameter the longest strut is less than 3-1/2 feet. There are *250* of these critters, so the degree of triangulation is huge. The math says it not only works... it's climbable... and has a hefty reserve factor even in a 70 mph wind. But the 30-foot dome may indeed need to be considerably heavier stuff. (I need to sit-down and model that critter. My lack of data on this is starting to bug me).

On the fabric aspect, I had been thinking about canvas, specifically treated duck. I will order some samples of 10oz and 16 oz treated duck so I can do the touchy-feely thing. If I use this stuff the cover will weigh nearly as much as the structure itself.

I agree with you completely as to making a shell that isn't layered. I have seen video of the results of trying this approach. One edge caught by the wind and the structure will inflate and become a kite. (Might be fun to watch, but once they figure-out whose dome it was, I don't want to be the subject of a lynch-mob!). We would sew the dome cover into two halves on the 20 foot, 4-halves on the 30-foot, with the sides lacing together corset-style and using elastic cord as the lacing. The "seams" would get covered-over with an integral flap with velcro to hold it tight and keep any loose edges from catching the breeze.

Thanks again for your thoughts!

just be careful with your math..................

[Roark]

Ooops. I guess this is a case of the halves... And halve-nots.

Sorry. Couldnt resist.

[ygmir]

Ooops. I guess this is a case of the halves... And halve-nots.

Sorry. Couldnt resist.

if it's fabric and rope, it may be halves, and halve knots.........

[Roark]

Oh... that's bad. Punny as hell tho!

Maybe we should rename Ygmir. "Loki" fits (Nordic god of fire, chaos and mischief!)

[ygmir]

Oh... that's bad. Punny as hell tho!

Maybe we should rename Ygmir. "Loki" fits (Nordic god of fire, chaos and mischief!)

might be a good one, if not for that whole thing about where Slepnir came from, how and why..........

[Dr Helix]

Okay I'm going to throw an alternative out here. Ever heard of shrink wrap? It's what they cover cars in for transport, boats, etc. I built an 18 ft diameter dome some years ago as a party place and covered it with shrink wrap fabric. You tape it to the base and then use a heat gun to stretch it tight as a drum over the frame. You can buy zippered windows and doors that tape in to let air in and also vents. You can't set fire to it (it just melts slightly and stops) It comes in white or clear so you can have a field day lighting it (I had party lights bounce of of it that could be seen inside AND outside). And it had no problem with 50 mph winds although that's all I can vouch for. Downside? Initial expense is a bit steep as the heat gun is a few hundred dollars. And you can't re-use the fabric. One and done unfortunately. I have never seen it used out on a dome on the playa but if I ever brought my dome out there I sure would try it. Like I said, just another alternative. Good luck.

[Roark]

Doc: I might have to research this. I already have the heatgun. The one-time-use aspect is bothersome, but perhaps for the first year on the small dome it might be interesting to try!

Thanks!

[ygmir]

Doc: I might have to research this. I already have the heatgun. The one-time-use aspect is bothersome, but perhaps for the first year on the small dome it might be interesting to try!

Thanks!

if you do this, please, put a big garbage bag at the very top, for a "reservoir end".

[Dr Helix]

Doc: I might have to research this. I already have the heatgun. The one-time-use aspect is bothersome, but perhaps for the first year on the small dome it might be interesting to try!

Thanks!

If you do, an important tip. Do NOT try to shrink it from the inside. The first year I did it I was working inside with the gun when suddenly small melting spots began to appear, then bigger and bigger and then the whole thing collapsed! The heat had no where to go and accumluated to the point where it melted the top. Lesson learned, rebuilt it, and it turned out fine the next go. Good luck.

[theCryptofishist]

Oh... that's bad. Punny as hell tho!

Maybe we should rename Ygmir. "Loki" fits (Nordic god of fire, chaos and mischief!)

might be a good one, if not for that whole thing about where Slepnir came from, how and why..........

Then you're not a genuine trickster. Tricksters don't go for rigid gender boundaries.

[ygmir]

Oh... that's bad. Punny as hell tho!

Maybe we should rename Ygmir. "Loki" fits (Nordic god of fire, chaos and mischief!)

might be a good one, if not for that whole thing about where Slepnir came from, how and why..........

Then you're not a genuine trickster. Tricksters don't go for rigid gender boundaries.

exactly!! I am not, nor do I claim to be Loki.
I knew Loki, Loki, was a friend of mine. You, Madame, are no Loki.

[theCryptofishist]

Oh... that's bad. Punny as hell tho!

Maybe we should rename Ygmir. "Loki" fits (Nordic god of fire, chaos and mischief!)

might be a good one, if not for that whole thing about where Slepnir came from, how and why..........

Then you're not a genuine trickster. Tricksters don't go for rigid gender boundaries.

exactly!! I am not, nor do I claim to be Loki.
I knew Loki, Loki, was a friend of mine. You, Madame, are no Loki.

Then, is there a Loki on this board?