Geodesic Dome Construction (Tips and Tricks)

[don]

THANK YOU EVERYONE FOR THE FEED BACK! i WENT ON EBAY AND BOUGHT A 35' PARACHUTE. THE RADIUS OF MY DOME IS 8.5' THUS MAKING THE CIRCUMFERENCE OF THE HALF SPHERE ABOUT 26.5' OR SO. I KNOW THAT THEY TRAP THE WIND AND CAN CREATE PROBLEMS THAT WAY, BUT I NEEDED SOMETHING FAST. And AS I UNDERSTAND, TARPS CAN TRAP THE HEAT AND CREATE A SAUNA EFFECT, NO THANKS!

ANY SUGGESTIONS ON ATTATCHING IT TO THE DOME?

dON

[kampkalamazoo]

You can grab pinches of 'chute material and tie them off with cord...Especially if the chute COMES with lines intact! You can also use zipstrips. No reason to punch holes in the material, except for wind vents. I'd suggest tying off at the top and around the sides as well as at the bottom, and perhaps using cord in SOME locations so as to make it easier to open up when you begin to slowly roast.

[don]

sounds great, thanks!

[Elemental666]

um, So would a 28ft parachute fit my 12ftR 3/8 3v?

I mean which measurement is 28ft exactly?

[Martiansky]

Elemental, I thought you had your cover made? A parachute sounds kinda appealing though somehow......

I am not sure that my billboard vinyl cover will be completed before I have to leave so I may be using tarps this time around....

[robotland]

um, So would a 28ft parachute fit my 12ftR 3/8 3v?

I mean which measurement is 28ft exactly?

I believe that 'chutes are measured EQUATORIALLY, and not as a section of a circle- In other words, the figure given is the distance from a point on one side to the point up, over, and down to a point directly opposite of it.

[Martiansky]

A 'chute hanging inside the outter covering could be kinda cool looking and maybe even make a inner wall for heat.

[Elemental666]

um, So would a 28ft parachute fit my 12ftR 3/8 3v?

I mean which measurement is 28ft exactly?

I believe that 'chutes are measured EQUATORIALLY, and not as a section of a circle- In other words, the figure given is the distance from a point on one side to the point up, over, and down to a point directly opposite of it.

So basically, 28ft would be half the circumference of the vertical plane? Jeez Damn, this mother is HUGE!!!!!

Heh, now where did I put those zip ties...

Oh, M, the chute is indeed for the inside

[robotland]

If it's that generously-sized, you can just scramble up onto your domeframe and grab handfuls of parachute, knotting them to the frame as you go!

[Elemental666]

heh, um, ok it (the chute) doesn't look big enough, but i guess we'll just see. It isn't necessary I just thought it would be a good idea... I can use it for extra shade if necessary...

[robotland]

One last tip before I roll- Last year I bundled all of my struts in tens and fifteens, tying them with lengths of light nylon cord...This year I switched to palette wrap, which works MUCH better and keeps everything from rattling on the long haul. It takes a little getting the hang of- Pulling the wrap tightly enough to stretch it a little and "weaving" it at angles does the job. Just have to remember to pack the damn tape so I'll have it on the return trip!

[falk]

I made a supply of straps and bundle them 10/bundle.

http://www.efalk.org/OasisDome/photos/dsc_0798.jpg

It's a bit of work to tighten 'em up though.

[robotland]

Dang....she's gonna be a BIG one!

[mr_delicious]

Does anybody know how much taller than the radius a 5/8 dome would be?

Desertdomes.com says that "The odd frequency domes are not exactly half of a sphere. They can either be a little more or less than half. 3/8 and 5/8 are not exact numbers, they are mainly for reference."

I want to hang a platform on the inside of the dome and need to figure out how tall the dome needs to be to maintain a comfortable amount of head room. As estimates of the height, I got 15-25% greater than the radius.

Also, would a 3v 5/8 dome made out of 3/4" thinwall be strong enough to support the weight of four people on a platform (as long as the strut lengths don’t exceed 5 ft)?

[Martiansky]

I built a 2V out of 3/4" conduit that is about 16' in diameter......Now I want a BIGGER dome! Muwaahahhahaa! They're addictive!

[robotland]

Also, would a 3v 5/8 dome made out of 3/4" thinwall be strong enough to support the weight of four people on a platform (as long as the strut lengths don’t exceed 5 ft)?

How big is your dome going to be? (No java here, so I can't plug the 5' figure into Tara's calculator!)
If you're suspending the platform from the upper vertices around the top of the dome, you'll be able to support PLENTY of weight providing you design the platform carefully. My first experiment with domedecks involved a heavy wooden platform hung from the five points and "North Pole" of an 18' dia. 2V- Easily held six people. Nowadays I sit the deck ON TOP of the dome, using a coupler that stands up from the top pentagon at its vertices. Rock solid. In fact,the two upper domes of the Snowman, the wooden deck AND the playa luge slide all rested on those six points. No problemo.
If it's a suspended deck for starters, I suggest that you measure and build a platform that's the correct size to insure that the force on the eyebolts is straightline- In other words, that you're not bending the eyebolts. (They stand a chance of shearing if you load them to the sides.)

[robotland]

Just put the 18' 2V up in the woods as a winter storage barn...I tried a new (to me) technique- Assembling all six of the pentagons first, and then connecting them. I'm recovering from carpal tunnel surgery, and have limited use of my left hand, so instead of holding the top pentagon overhead I ran a line between two trees and threw another line over that. Suspending the top penta from its center, I went around on a ladder and connected it to the lower five. Went really fast and easily! The trick is going to be finding two trees on the playa, though....Might have to get help with that part. But the connect-the-pentas part's a keeper. Leaning one penta against your trusty 6' A-frame ladder while holding the other gets you started, and then they stand up by themselves if you've tightened the bolts.

[BadDawg]

Why don't you try for a "Trampo-Dome" it goes up very easy & take down is almost as easy. My 14' was just great this year. I'm looking for a 10' or 12' trampoline frame to make a new one out of for the coming year. The 14' will be the new kitchen area for the Kamp Apokiliptika this coming year. And many thanks for the hand-made medallion.

[Martiansky]

Bad Dawg, do you have any pics of your tramp-dome?
I missed out on a tramp frame this spring, it had been set up all winter and got bent a bit and the people tossed it!

[robotland]

I like the idea of a tramp in a BIG dome, so you could boing up and grab a vertex and hang....or have a platform that you'd HAVE to boing up to, and then jump down to exit....(or a slide- They're clearanceing them at Menards....)

[regionalchaos]

I saw a dome with a tramp as the upper platform. It looked comfy to lounge in, but I'd be afraid of some idiot jumping off!

Btw, I'm planning on building either an 8.5', 2v or 11.5', 3v dome for 2006. I think the decision on the size will largely be a $$ issue. Although I was excited to find a local dealer that gave me a sub 5$ quote on 3/4". Can electritions or metal shop workers get deals on thinwall? I think I'm going to try looking some local metal recycling places as well...

[robotland]

From my experience, the contractor rates on bulk materials are hardwon unless you're buying LOTS. But you should be able to find scrap conduit galore, especially if you're willing to do a little extra hacksaw work. And never, EVER pass a dumpster without looking in. I've built whole domes from mongo (free from the trash) conduit. Just put my Generic 2V up for the winter, to store dome parts in!
MIDWEST CONDUIT REPORT: Average price for a stick of 3/4" EMT in Kalamazoo, Michigan, October 9th: $5.27.

[Martiansky]

I wonder who it was that built that huge dome out of aluminum irrigation pipe? That thing was HUGE and awesome! Wish I would've checked it out after it was done.

[regionalchaos]

MIDWEST CONDUIT REPORT: Average price for a stick of 3/4" EMT in Kalamazoo, Michigan, October 9th: $5.27.

It's the same price @ home depot out here in eugene. I had a different dealer quote me 4.94 though!

[robotland]

We'll have to watch the prices, with the disasters happening everywhere....(*Holding fingers to forehead*) ....I predict another spike in steel prices.

[regionalchaos]

We'll have to watch the prices, with the disasters happening everywhere....(*Holding fingers to forehead*) ....I predict another spike in steel prices.

Yea, I hope it doesn't go up too much more too soon. I don't have the scratch to buy all 60 tubes I need yet. But I'm thinking I should probably start buying them 10 at a time. I can start to work, it will motivate me, and I'll protect myself from price increases... I don't think the price is going to drop... Someone told me they have a friend that can get Thinwall at cost, but I'm not sure what kind of a deal that really means. I need to do some follow up networking.

[mr_delicious]

Is it ever safe to use 1/2" conduit? I've read all the posts that warn against it, but robotland says he had an 18' 2v that held 6 people on a suspended platform (with 3/4"). If I decreased the diameter to 15.6' and made it a 3v dome using 1/2" conduit, would I still be pushing it? Could it hold any weight? The longest strut would be about 3.35 feet.

The answer is still probably 3/4", but I can get my 45 sticks of EMT for about $85 instead of $240 if I go with the 1/2".

Just wanted to bitch about the price difference.

[robotland]

(Whenever a reply starts with "In theory....")

In theory, using 1/2" would be FINE. But as soon as any struts start to bend at all they'll fold like me playing poker. I've happened upon troves of 1/2" often enough that I've even considered some sort of triangular "orthotic device", like a brace inside each triangle, to keep the struts straight. Too much work. If you find a dumpster full of 1/2" AND OLD STREET SIGNS, you could rivet the tubes to triangles of aluminum, and that would double as support AND shade. You wouldn't even need to do each one- Just every "other" one, if that makes any sense.
if you have them around, pick up yard-long pieces of 1/2" and 3/4", and try to bend them in your bare hands. Some types of 1/2" are almost BUTTERY, and the toughest I've seen'll still fold like a French battle flag. I've noticed some bowing in the 3/4" struts from my biggest dome, and have retired it to domestic use as a winter art-supplies barn rather than try to correct their posture. (And so I can upgrade to a 3V!)

[regionalchaos]

Wooo Hooooo!

OK, I sold my old car and now have the scratch to buy my dome supplies. I used the dome calculator over at dessert domes to spec out an 11.5' radius 3V dome. Each strut would be under (but maybe just barely under) the 5' mark. This way I can get 2 struts per 10' tube.

My question now is if anyone thinks I'll have problems with 3/4" tube? I would like to have it strong enough so that I can hang a hammock off of a few joints. I have read several people that say that 3/4" is fine as long as the struts don't get past 5', but what if they are close to 5'?

I think I'm going to build a scale model soon, then purchase the gear afterwards... I CAN'T WAIT!

[capjbadger]

Wooo Hooooo!

OK, I sold my old car and now have the scratch to buy my dome supplies. I used the dome calculator over at dessert domes to spec out an 11.5' radius 3V dome. Each strut would be under (but maybe just barely under) the 5' mark. This way I can get 2 struts per 10' tube.

My question now is if anyone thinks I'll have problems with 3/4" tube? I would like to have it strong enough so that I can hang a hammock off of a few joints. I have read several people that say that 3/4" is fine as long as the struts don't get past 5', but what if they are close to 5'?

I think I'm going to build a scale model soon, then purchase the gear afterwards... I CAN'T WAIT!

My dome last year was 3/4" EMT with strut lenghts of 4.7" and 5.3" (or abouts). No problem at all hanging stuff off the joints. I hung a "skychair" that I'd nap in off one vertext with no movement at all. I could even climb the uncovered dome as long as I kept my feet within 6" or so of the joints (BTW, I weight about 150lbs). Basicly you'll be fine unless you try hanging off the center of the strut.

Once you lock down that last joint, you can really tell how solid it is. The only warning is that domes are only strong when the bottem edge is linked in some way to the ground (by gravity, stakes, etc...). The real strienght of the geodesic system is when its a full sphere. For domes, the ground acts as the missing half of the sphere and gives the whole thing stability.

Badger