6V Dome - LARGE Dome Covers (Patterns and Calculators)

[Geobear]

Hey guys! So I most recently built a monster of a dome.
Specifications
6V - 555 Poles [1in EMT Conduit]
Diameter: 48ft
Weight: 1700lbs

What i've noticed after around 4V Sizes, information for pattern and dome cover calculations become very slim on the internet. I'm ready to invest in a dome cover but I need some help finding the best resources I can use to sew a high quality cover on my own. I'd like to be able to sew this cover very accurately, and be able to sew in things like zipper doors/ windows/ vents as well as install circular frame doors. I've also been interested in using clear marine vinyl for the front for a transparent look. I'd like to start this topic as a help station for LARGE geodesic domes and look forward to seeing what kind of help this will send our way. I posted my key questions to the community below.

1) Does anyone have some good links, references, tutorials, or even people I can talk to, to make a quality 6V LARGE dome cover?
2) What is the best method for making a Dome Cover for such a Large Dome?
3) What is the best method for sewing a Large Dome Cover to keep it tight and not have seam lines?
4) What material do you recommend for outdoor burns (WeatherRain Resistance // UV Protective) while still having a very Translucent tight wrap look? Right now I've been thinking about using vinyl coated Polyester based off PacificDomes looks.

Below I attached a picture of kind of the goal for this dome cover project.

Thanks for any help, I hope this helps send me in the right direction.

[some seeing eye]

1 Dome covers are very niche business
2 Ultra cheap, shrink plastic, one use, theoretically recyclable; China made vinyl; Dacron
3 Theoretically you could sew arcs, but I have never seen
4 Dacron

You know there are many dome cover threads on ePlaya you can search?

[Geobear]

So far I've found out the material I think I need it PVC 4-Way Stretch Vinyl. Its got all those qualities, looks sleak, and water beads off of it. Does anyone have more information on this fabric, I attached a link to the fabric below. Dacron looks nice but from what im getting its not completely rain proof, this Dome will probably see more rain than your average Burn as our regionals see rain almost every year. I understand they're are plenty of dome threads out there, and I will continue to read them, but a lot of them are so buried in actual dome construction or small dome covers that it makes it very hard to find serious information from experienced domophiles. I'm hoping this forum will help surface some really good methods for the whole burn community to craft from and use as a resource. Large clean dome covers may be a niche market that takes a team full of skilled members in their own niches (industrial sewing, designing, etc.), but I still think we can create a refined pool of information for us to build off of. Maybe its already out there, i'm just having trouble finding it! Appreciate the help! P.S. Some Seeing Eye - I got your message and gave your guys a call, they are extremely helpful and we are discussing the project further

http://www.mjtrends.com/categories-Stretch-PVC,Fabric

[some seeing eye]

You might give some thought to the weight of your cover and how you are going to get it on and off. The other consideration is that the seams and fabric of the top pentagon, the nipple, have to support the weight of all the rest of the cover below them. Keep us all up to date on your adventures.

BTW there is sail cloth laminated with mylar, but it is expensive. Some people on ePlaya like cotton canvas, but I think it is too heavy. YMMV!

Of course if you have access to a crane, all problems are solvable.

[GreyCoyote]

A few comments:

Consider carefully if you really want a waterproof cover. Waterproof means no air exchange, so you will need to condition or force-ventilate the space. (We handled this with a "smoke hole" in the middle and a ceiling fan mounted to exhaust/move some air. A rainfly covers it during inclement weather). Waterproof means using non-wicking thread and then sealing all of your seams - a really tough job to do unless you put the cover on the dome to do it.

Do you have the ability to sew vinyl? It handles very differently from canvas or fabric. You will need to play with stitch-per-inch and tension settings so you have a strong joint that can flex without tearing. This can be tricksy. Just because the vinyl can stretch doesnt mean the thread on the seams will.

Vinyl is bad news for re-radiating heat. If you use any color but white, it will absorb solar rays and reradiate them in the infrared. Occupants will feel this as heat unless you use an IR-blocking liner (which presents its own set of problems).

Unless you plan to make each gore just zipper into the next, you will need an industrial, long-arm sewing machine. Expensive, but worth it. Especially for a large dome cover, a home-type machine made in the last 50 years wont work. (But an old Singer 66 might just do it).

You are building a 6V so it will be exactly a half-sphere. I can generate the gore patterns for you if you wish. PM me.

Suggest making the sides capable of being rolled-up a couple of feet during use. This gives you excellent shade and lots of airflow.

For a public structure, consider two doors. Safety and easy access are important factors to consider. How you engineer the doors is critical to the integrity of the structure. How you implement these openings on the cover is also very important.

Engineer lightning grounding into your design. A 20 foot dome needs one grounding stake. Anything larger needs at least two. A good rule of thumb is about one stake for each 40-50 feet of circumference.

Make your cover your dome anchoring system. All you need to do for the frame is prevent lateral movement with a few well-placed stakes. Use the cover to tie-down the dome. Engineer a quick-release system so in a really hard wind one person can jettison the cover in a controlled manner to the lee side.

Make the cover a little longer than the dome needs. There may be occasions where you want to roll the cover under the bottom struts. Having an extra foot of length lets this happen.

Finally: those svelte covers you see on adverts dont really exist in the real world. Ever wonder why most of those photos are done with dark, dramatic lighting, or from a distance? Yup. You got it. Even the BEST fabrics will expand and contract with heat and weather. The base circle on a 40 foot dome is a circumference of 126 feet. Assuming a 1% change from high noon to midnight (and it will likely be far greater), a cover that is snug an nice at one end will be 1.5 FEET longer (or shorter) at the other end of the temp scale. You just cant get away from this (but there are some dodges involving corsets!)

I saw your dome at flipside BTW: Great job!!! We were the 20 foot 4V in the Badlands serving bacon tamales.

[Jovankat]

I love it when GreyCoyote talks about domes

[Elderberry]

Semi-related question. GC, you mentioned lightning grounding. I was just wondering how deep/long you would suggest the grounding poles be? (no pun or innuendo intended ) And would this also be the same for a generator?

[GreyCoyote]

JK/ElderB: The standard for ground rods is 8 feet, but we all know that isnt gonna happen on the playa. There is a fairly good conductive layer just a couple of feet down. If you can get into that, so much the better.

As to generator grounding, you may not need to ground it if its a floating neutral output and a small genny. On a bigger genny, or one that has a center-tapped output (ie, produces both 120 and 240 volts) where the neutral is NOT FLOATING (its floating on most box store gennys), then it really should be grounded and in fact insurance may require it to be grounded. For these I would use the same ground-rod setup as for the dome.

The final decider will be the genset manufacturer. Some need a ground, and will have a lug for it. Others have no such provision. When in doubt, ground it. Its a do-no-harm thing.

[some seeing eye]

There has been some debate on radio discussions of playa as ground. Lightning seeks any imperfect ground. So suggest burying a horizontal ground rod to the depth of damp playa. Thx for GC for posting, domes are unlikely electric field attractors with nearby pointy metals. But hey, safety first!

[GreyCoyote]

Very true, SSE.

The truth is a dome is an excellent faraday cage. If we could put a ground plate (or grid) for the floor, tie it into the dome lattice electrically, it would be a very safe place in a storm. Even a direct strike wouldnt hurt anyone inside since there would be no difference in potential.

My worry is being inside the dome (or near it) during a strike without that floor grid. Now we have this massive charge gradient between the jump-off point on the frame and the folks nearby. That gradient tends to travel on the surface (since its usually wet with rain) and that gradient can be many thousands of volts per linear foot. Just standing on your two feet a few inches apart means that gradient can easily be fatal.

The goal of grounding a dome is really two-fold:

1). To control the point of jump-off, making sure there is no arcing from the frame to persons in close proximity.

2). To bury, as much as possible, the charge gradient into a more highly conductive layer that will result in a smaller surface charge gradient.

BTW: if you can point me to any recent discussions of radio grounds on the playa, I'd appreciate it. I have been tinkering with the idea of bringing an OCF dipole and a vertical for an HF rig, and could benefit from others experiences!

[Elderberry]

Thanks GC.

[some seeing eye]

GC, we had this discussion on grounding: https://eplaya.burningman.org/viewtopic ... +grounding. There are maps of ground conductivity which suggest the playa is not a great ground, so it would be interesting to bring a ground meter and test at various depths. To your idea, hopefully dry playa is less conductive than wet, so inside your dome you are standing in nonconductive shoes on a relatively nonconducting a few inches of dry playa, overlaying the wet earth ground plane. And of course hope the lightning strikes BMIR, Legba or something else!

I think there have also been some generator grounding discussions. I met some of the Lance camp people a few years back, but did not look into their grounds.

(I tried to participate one year in Megavolt's Faraday cage, but it was too popular)

hahaha, this thread is drifting...

[mooserider]

To continue driving this drifting thread into the ground , here's another thread I started regarding grounding, specifically for antennas.

https://eplaya.burningman.org/viewtopic ... 77&t=73241

[Token]

Tyvek makes for a great cover. Easy to work with, light weight. Can sew or tape/glue. Pre-washing reduces shrinkage and softens the stuff a bit. Requires ventilation.

[melodiousdirge]

MY dome isn't nearly as large as yours, at only 24 feet, but I found similar challenges finding info on making a cover - everyone's got instructions on making the damn struts and nobody seems to have much advice on covers. What I did was to use recycled billboard vinyl, with the unprinted (white) side out. This vinyl is pretty heavy - my cover easily weighs 100lbs, so yours would be like 400lbs, but the stuff is cheap, sturdy, gluable, and easy to come by. I assembled it by cutting the vinyl into pentagons and hexagons with a little slice missing, to be pulled together and make hexagonal geodesic segments:



Then I used HH-66 vinyl cement to glue all the seams together until I had a cover the same shape as my frame. For a dome as complex and large as yours, I think would go with a leaf pattern (like the one here: https://waymoot.org/home/dome/) instead to make an approximately spherical cover, ignoring the angles and just counting on the fabric to drape approximately right. A friend of mine did a leaf pattern cover using tarps and a sewing machine and it worked out well for him. The reason I suggest this, is piecing together all those polygons was a hell of a task, even with glue instead of sewing. Sewing would have been ridiculous.



The vinyl lets in quite a bit of light, and some heat during the day, but I put in two window flaps and a door, which keeps it pretty reasonable in there, even on the hottest days. A smoke hole at the top would probably work even better, but I didn't really want to have to climb a ladder constantly to get to one.

Something (as someone else mentioned) to really think over is how the f&#% you're going to get the cover over top of the skeleton. After I scratched my head on that point for a couple of weeks I decided to hang the cover INSIDE the skeleton, so I could put it up myself. The vinyl is quite heavy, so me trying to wrestle it up and over the dome alone would have been dangerous and frustrating. I accomplished this by putting 5/8" grommets at each vertex, sticking a 3" long heavy duty bungee loop through the grommet, and then hooking the bungees over the vertices with carabiners. The flexibility in the bungees keeps the cover relatively taut, while allowing it to move a bit under heavy wind.



In the inside shot you can see the ads printed on the inside, along with the reinforcing discs I put at each vertex to strengthen the attachment points:

[trilobyte]

There's alreay a lot of great advice in this thread. A couple things I'll note. +1 to everything GreyCoyote said, especially about making a fully water-proof cover. That can make for an awfully uncomfortable experience if it gets too hot (by day, or with a lot of people inside it at night). Venting is key, and you may also want to consider your entryways at ground level. I'm sure there are other great examples, but El Circo (started in the late 90's, and stopped in 2007 or 2008) had a really great solution, their entrance could open up further. I think that they had 4 main entries on a 30-40 foot dome (two towards the frontage, two towards the back that they'd use for backstage access when they did their infamous performances/fashion shows), and when conditions were right they were able to easily open out the gap between those entrances on the frontage side (people would still have to walk between the struts, of course).

Dome covers are indeed an extremely niche market, which is why the few people who offer them are either incredibly pricey or only really do it as part of a dome sale. A friend who's a lot more serious about structures than I am once told me that when it comes to domes, if you want a really good cover, expect it to be about twice the budget - and twice the pain in the ass - as the dome's framework itself. My gf and I used to have an 18' dome with cover, and found that to be true.

As an alternative to things like billboard vinyl or other poly materials, consider a good heavy canvas. Sail cloth is available in pretty large sizes/widths (so your seams would be along strut-lines and not be visible at night), and can be pretty easily stitched together using an industrial sewing machine. If you wanted alternatives to canvas, you may also want to look for stage production sites to see what kinds of materials they offer for scrims, screens, and curtains. Keep in mind that lighter weight stuff will not only be lighter weight, but more prone to tearing or getting holes.

Good luck with the project, and keep us posted on your progress!

[some seeing eye]

Some 24' 5/8 dome covers fabricated in China of vinyl for our camp were about 500# each so melodiousdirge might do a weigh in to check his. Hanging the cover inside has a lot of advantages! Many commercial makers use a material that can be glued, rather than sewn to save on labor costs. And yes agree, budget the cover before committing to struts. The "cheap" method is to wrap Aluminet in great circle arcs. The El Circo dome also had vent panels up high I believe and was made by Pacific. For our 65, we had to cut out some panels in the vinyl up high mid event for ventilation. It required a DPW crane to get it on and off. I have previously listed and PM connections to an individual who sews covers as a side project, was part of our 2006 project for complete fabrication of 2 24s and a 65, and has since fabricated struts and covers for more than a dozen domes up to 80.

[melodiousdirge]

Some 24' 5/8 dome covers fabricated in China of vinyl for our camp were about 500# each so melodiousdirge might do a weigh in to check his.

500#! Mine doesn't weigh that much. It may weigh more than 100# as I said earlier but I don't think by too much. I can heave it around myself when it's rolled up with a couple straps around it. I guess it could be as heavy as 150# but I don't think any more than that. Something else to consider is that a dome cover is a pain in the butt to fold up, and the heavier it is, the harder it is. Think of a fitted sheet that weighs hundreds of pounds and is made of heavy fabric.

[mapp3d]

Hi everyone.
Greetings from Madrid.
I found this post checking and looking for some information about other geodesic domes companies.
Actually, I have an Event Geodesic Domes Rental Company in Spain, https://www.Geodomes.es and I know Burning Man but I never was there, and I really like it, maybe in a few years I´ll visit the festival.
Reading the first post, I just want to say you congratulations for your dome, but in my opinion, the best dome I found in internet that was built in Burning man is this one ( sorry, it´s a link to my website blog post cause I wrote about it) https://www.geodomes.es/en/led-geodesic-dome/.

This dome is really impresive, we are working with led domes, and when I saw this dome, I felt in love about it, just really nice.
Maybe you could tell me more about any other domes in Burning Man, cause different to these ones, I don´t know if every year there is a dome installed in Burning Man, but I´d like know more about any other Domes in Burning Man.
Thanks guys!!

[Sham]

Hi everyone.
Greetings from Madrid.
I found this post checking and looking for some information about other geodesic domes companies.
Actually, I have an Event Geodesic Domes Rental Company in Spain, https://www.Geodomes.es and I know Burning Man but I never was there, and I really like it, maybe in a few years I´ll visit the festival.
Reading the first post, I just want to say you congratulations for your dome, but in my opinion, the best dome I found in internet that was built in Burning man is this one ( sorry, it´s a link to my website blog post cause I wrote about it) https://www.geodomes.es/en/led-geodesic-dome/.

This dome is really impresive, we are working with led domes, and when I saw this dome, I felt in love about it, just really nice.
Maybe you could tell me more about any other domes in Burning Man, cause different to these ones, I don´t know if every year there is a dome installed in Burning Man, but I´d like know more about any other Domes in Burning Man.
Thanks guys!!

The above post appeared to be a spam post, but a closer look, it seems to be a legit person who makes geodesic domes in Spain. It does not appear that these domes are offered for sale, but rather showing and showcasing the domes in this thread.
I am leaving this post and user up and running.

[mapp3d]

Hi Sham,
yes, my post has a link to a post I wrote about the Burnin Man domes. It was not my intention write anything as Spam, just found the first post googling and I just joined the conversation with in my opinion, relevant comment.

[some seeing eye]

The "Radiance Dome" may be one you are thinking about shown in playa videos. I've met them, they are out of Eugene. The dome has its own enclosed trailer for hauling and storing the struts and light modules with cases for the modules to make them easy to stack and protect them in transport. They also have some smaller sound reactive geodesic spheres. Great people.

I think Bucky would have really loved the burn.

[mapp3d]

Yes, actually, is the only one I know from Burning Man, that is why I was asking for more info about other domes installations in Burning Man.
We are making our own led dome, but just with led bar fixed to the dome pipes, and when I saw Radiance Dome, I loved it, fantastic job!!

I was trying last august programmin with GrandMa lighting console and the result is really beautiful, I´ll not include the video to not make Spam here, but led plus geodesic domes are a very good mix.

Best