parachute dome cover question

pbmaniac2000 · Post by **pbmaniac2000** » Wed Apr 23, 2008 12:56 pm

I am trying to figure out how I am going to cover my dome for this year. I have not decided on how big the dome will be either. Between 15 and 20 feet. I was wondering what size parachute I should look for. Whats the general "rule" for parachute to dome size?

aranryan · Post by **aranryan** » Wed Apr 23, 2008 1:22 pm

Dude, I'm building my own 15ft dome this year and after TONS of research have found that parachutes are the opposite of what you want.

A) They catch the wind and will either toss your dome into the next camp over or be so loud and obnoxious as to make conversation difficult.

2) They provide a little shade but no UV protection

IV) If it rains, they aren't water proof.

I would recommend using Aluminet or getting some heavy duty silver tarp. Sure its a bit more expensive but if you're going to use your dome more than once a year, totally worth it. Check around these forums and you'll find a multitude of help.

I found this page to be helpful:
http://www.weasel.com/dome_cover.html

Good luck and if I can help in any way, send me a message!

gyre · Post by **gyre** » Wed Apr 23, 2008 1:31 pm

Check out silvicool if you can't find Aluminet solid.

Teo del Fuego · Post by **Teo del Fuego** » Wed Apr 23, 2008 5:20 pm

fucking billboard vinyl. it's free and it blocks the sun real good

gyre · Post by **gyre** » Wed Apr 23, 2008 7:12 pm

Teo del Fuego wrote:fucking billboard vinyl. it's free and it blocks the sun real good

I don't think it's vinyl.
It's better.
They charge for it around here, but cheap.
Some of it is translucent, some opaque.
I've wrapped it right to a tent to block the sun.
Even without an air gap, radically cooler.
Heavy though.
And silvicool is reflective.

MikeVDS · Post by **MikeVDS** » Wed Apr 23, 2008 9:37 pm

Parachutes are easy and work well. There are better options if you're willing to spend the money and/or time.

The rule for sizing parachutes is that that diameter of the parachute is going to fit over half the circumference of a sphere with the same diameter.

So if you want a 15' diameter dome you need to find the circumference of a half circle with 5' diameter. The formula is Circumference =pi * Diameter. Since we want 0.5 * Circumference, we get the formula,

Parachute Size = 3.14 * Radius.

So if you want 15' dome you get:
Parachute Size = 3.14 * 7.5 = 23.55 foot parachute.

I think it's easier to find a parachute about the right size and build your dome to fit that. Keep in mind there are some "magic" sizes that you can cut your lengths without much waste.

MikeVDS · Post by **MikeVDS** » Wed Apr 23, 2008 9:43 pm

That'd be a 31.4 foot parachute for a 20 foot dome. Somewhere between there would be good to start.

pbmaniac2000 · Post by **pbmaniac2000** » Thu Apr 24, 2008 10:36 am

Teo del Fuego wrote:fucking billboard vinyl. it's free and it blocks the sun real good

Yeah i have looked at billboard vinyl. My only thing is how do you sew it together?

My goal this year for burning man is to be as dust free as possible. I will be out there for two weeks. I know there is no such thing as dust free, but last year my wall tent didn't keep out much dust. Another thing for me is insulation. I have an ac unit, but want to run it as little as possible.

skeetsh00ter · Post by **skeetsh00ter** » Thu Apr 24, 2008 2:12 pm

I'm going to be using billboard vinyl for my dome this year. My current plan is to cut the vinyl into triangle shapes and put grommets around the edges so that 6 different triangle pieces of vinyl can be attached separately. Then I'll just use some clear packing tape to cover the seam.

keeps it [relatively] simple. no trying to sew the vinyl or having to heat weld pieces together.

aranryan · Post by **aranryan** » Thu Apr 24, 2008 4:19 pm

I've heard good things about this material. I might try it out. I have samples on the way. I think I'm going to go with a combination of an outer shell and inner shell. Not fully sure how to do it yet though.

http://www.radiantbarrier.com/temptrol.htm

Captain Goddammit · Post by **Captain Goddammit** » Thu Apr 24, 2008 6:35 pm

pbmaniac2000 wrote:
Teo del Fuego wrote:
My goal this year for burning man is to be as dust free as possible. I will be out there for two weeks. I know there is no such thing as dust free, but last year my wall tent didn't keep out much dust. Another thing for me is insulation. I have an ac unit, but want to run it as little as possible.

There sure as hell IS such a thing as dust free at BM. I do it every year.
You just need AC and a very well-sealed abode of whatever sort, and my biggest top-secret dust-fightin' weapon, a Rainbow vacuum! Those things were crazy ridiculous expensive new, but can be found reasonably on Craigslist.
The way they work is, you fill the bowl in the bottom with water, like a gallon or so... it sucks in through the water, using it as the filter. You empty the water when it's dirty.
If you just turn one of those on and let it run a while, it acts as the ultimate playa dust filter!
While everyone is choking and breathing through wet rags during a white-out dust storm, I'm hanging out, cooking, reading, doing whatever... in total comfort!
I don't know if the waste water even counts as "greywater", since the only thing in it is playa. I dump mine in one of my waste water barrels anyway.
I'm bringing two this year.

Isotopia · Post by **Isotopia** » Thu Apr 24, 2008 7:30 pm

Do NOT use a white parachute unless you have something opaque either beneath or on top of it.

Also, assuming your dome is at or approximately near a half sphere you probably want to figure out either radius, circumference or diameter. Settle for works best and than get an approximation from here:

http://www.desertdomes.com/domecalc.html

Good luck.

Bob · Post by **Bob** » Thu Apr 24, 2008 9:05 pm

You could tie-dye that white parachute.

Ugly Dougly · Post by **Ugly Dougly** » Fri Apr 25, 2008 9:42 am

Isotopia wrote:Do NOT use a white parachute unless you have something opaque either beneath or on top of it.
Good luck.

Ya, tends to make a greenhouse effect.

gyre · Post by **gyre** » Fri Apr 25, 2008 11:00 am

For the same reason, light colored tents are usually hotter in the sun than dark colored ones.
It used to baffle me that the airtight fly would make my tent cooler.
It was blocking heat.

Light colors are good in the cold though.

Ugly Dougly · Post by **Ugly Dougly** » Fri Apr 25, 2008 11:32 am

Probably best would be silver tarp, at least on the top. Many people add a second layer for insulation. You might even want to leave a small hole near the peak to let the heat vent out.

gyre · Post by **gyre** » Fri Apr 25, 2008 4:52 pm

Once you have an opaque layer, reflective is good.
White is usually safer unless you have something truly reflective.
The right green is a good infra-red material, but I know no way to be sure of the right shade.
Many of the good tarps have a black or metal layer in the middle to block light and heat.
Reflectix works well, but I don't think it would work as an outside layer.
Unjon has used it inside to good effect.

I plan on trying silvicool if I can't find a source for solid aluminet.
There must be someone overseas who can get us some.
Maybe we should remind the dealers of mesh aluminet that there are some of us that would like to see it here.

MikeVDS · Post by **MikeVDS** » Fri Apr 25, 2008 5:10 pm

White is fine as long as it blocks out most of the light. The problem is that most don't. I made a "shade" last year out of a white parachute and when the sides were pulled down, it was hotter. When the wind blew through it was a little better than being directly in the sun, but not great.