Geodesic Dome Construction (Tips and Tricks)

zen_greg · Post by **zen_greg** » Wed Mar 30, 2005 11:02 am

It sounds like you've gotten plenty of good advice and I hope your project is coming along nicely.

On the cutoff method, I didn't notice any mention of a simple pipe cutter. It is the method I've used and I really liked the results. No sparks, no fumes, and no noise. The best part was that I was able to achieve near perfect accuracy in my cuts. I was less than a 1/16th of an inch off on any particular piece and normally dead on. My concern with using saws was that the fudge factor would add up over all the pieces. Maybe the saw method is quicker but my pipe cutter only cost a couple bucks. I achieved some real efficiencies when I added in a pipe vise. The vise, which I clamped to a step-stool, held the conduit in place at about waist height while I used the pipe cutter. I bought the pipe vise on eBay for $10 and it has been one of my favorite tool purchases.

For flattening ends, I used a 3-ton arbor press. Even with the press, I found this to be the hardest part of the process. If you have a splurge allowance for this project, consider spending it on a press. Pounding out the pieces seems like an incredible effort to me. Also consider that you'll need something to pound on. The sidewalk will break. If you do decide to use a 3-pound hammer, be sure to wear hearing and eye protection.

Best of luck to you.

zen_greg · Post by **zen_greg** » Wed Mar 30, 2005 11:14 am

zen_greg wrote:On the cutoff method, I didn't notice any mention of a simple pipe cutter.

... because I must be blind. Sorry robotland and Dork.

zen_greg · Post by **zen_greg** » Wed Mar 30, 2005 11:15 am

It sounds like you've gotten plenty of good advice and I hope your project is coming along nicely.

On the cutoff method, I didn't notice any mention of a simple pipe cutter. It is the method I've used and I really liked the results. No sparks, no fumes, and no noise. The best part was that I was able to achieve near perfect accuracy in my cuts. I was less than a 1/16th of an inch off on any particular piece and normally dead on. My concern with using saws was that the fudge factor would add up over all the pieces. Maybe the saw method is quicker but my pipe cutter only cost a couple bucks. I achieved some real efficiencies when I added in a pipe vise. The vise, which I clamped to a step-stool, held the conduit in place at about waist height while I used the pipe cutter. I bought the pipe vise on eBay for $10 and it has been one of my favorite tool purchases.

For flattening ends, I used a 3-ton arbor press. Even with the press, I found this to be the hardest part of the process. If you have a splurge allowance for this project, consider spending it on a press. Pounding out the pieces seems like an incredible effort to me. Also consider that you'll need something to pound on. The sidewalk will break. If you do decide to use a 3-pound hammer, be sure to wear hearing and eye protection.

Best of luck to you.

Martiansky · Post by **Martiansky** » Wed Mar 30, 2005 11:22 am

I think I will try a pipe cutter for making the cuts. It doesn't leave burrs after sutting like saws do. I don't know why I thought that a pipe cutter wouldn't cut conduit! Duh!

I'm going to use a 6 inch chunk of steel I-bar to smash the ends of my conduit with and either a 3 or 5 pound mini sledge. So my right arm can be all huge and muscle-y when I get done! hahaha!

Tancorix · Post by **Tancorix** » Wed Mar 30, 2005 1:26 pm

I have several sledgehammers but the arbor press is the way to go. Harbor Freight has 'em cheap, Grizzly has some bigger ones if you need the extra squish power. For clean presses with straight lines and max control over what the final angles turn out like, you can't beat the arbor press.

spectabillis · Post by **spectabillis** » Wed Mar 30, 2005 2:15 pm

you guys are fantastic.

just sayin...

robotland · Post by **robotland** » Thu Mar 31, 2005 5:27 am

Maybe I'm just used to it, but I didn't find smashing the ends with the hammer/anvil method all that terrible. It does help to do it in bunches with breaks in between, just as you should when hand-cutting the struts. One caution if using a pipe cutter- The cut is beautiful and near-perfect, but also VERY SHARP on the inside. I personally find all of the round-and-round-and-round of the pipe cutter to be hell on my wrists, and instead just cut through a whole bundle of ten at a time with a hacksaw.

SNOWMAN UPDATE:
I was going to have a straight 16' slide coming off the second level, and have since had an epiphany- It's now a corkscrew slide down THROUGH the first level and out the side.....(Plywood covered with aluminum.)

robotland · Post by **robotland** » Thu Mar 31, 2005 8:53 am

SNOWMAN UPDATE UPDATE:

Eureka! I think I just solved the slide-weight problem! This weekend I run to the hardware store for about a dozen sticks of 1" PVC, which will make up the surface of the NEW slide. Held together by plywood brackets every couple of feet, and probably epoxied for good measure.

robotland · Post by **robotland** » Mon Apr 04, 2005 7:57 am

.....and NOW I'm changing it to a STRAIGHT slide, since the PVC won't bend enough to make the inside of the turns. Now it'll be an ANGULAR corkscrew, designed to make riders feel like checked baggage at an airline terminal. Start packin' those carbs, 'cuz you won't want a bony ass on THIS ride!

Elemental666 · Post by **Elemental666** » Mon Apr 04, 2005 9:14 pm

so yeah I'm building one of these jobbers, a 12' radius 2v. Don't worry I'll make use of the waste. Problem is I don't have a press and don't know anyone that does. So I called a bunch of machine shops in the area and I found 1 out of 6 that had a press.... I find that odd, but whatever, so I looked on harbor freight and the biggest press I found that won't take up my whole garage is a 1-ton arbor press. Will this be sufficient to press 140 ends?

Spaceape48 · Post by **Spaceape48** » Mon Apr 04, 2005 9:33 pm

I'm a first timer thinking of constructing my own dome. I heard simply sleeping in a tent is a bad move. My problems lie in what to use as a cover and how to attach it. Any suggestions or references would be much appreciated. Or, if you know of an alternative shade structure that is capable of withstanding winds that would work too. Basically, I just need a shade structure to put my tent in/under.

Thanks

BadDawg · Post by **BadDawg** » Mon Apr 04, 2005 9:34 pm

Elemental, just make your own press.
all you need is a 3 or 4 ton bottle jack
and some steel tubing and steel plate.
make a set of dies to suit your needs
and weld it up. the only photos I have
of the prototype I made are over
on another website. If anyone wants
the photos for making their own
let me know & I'll send them to you.

Elemental666 · Post by **Elemental666** » Mon Apr 04, 2005 9:36 pm

BadDawg wrote:If anyone wants
the photos for making their own
let me know & I'll send them to you.

PM sent

Elemental666 · Post by **Elemental666** » Mon Apr 04, 2005 9:40 pm

Spaceape48 wrote:I'm a first timer thinking of constructing my own dome. I heard simply sleeping in a tent is a bad move. My problems lie in what to use as a cover and how to attach it. Any suggestions or references would be much appreciated. Or, if you know of an alternative shade structure that is capable of withstanding winds that would work too. Basically, I just need a shade structure to put my tent in/under.

Thanks

If you follow some of the links off Desertdomes.com or seaarch for: Dome + "Burning Man" on google you'll find a bunch of links some of which include covering ideas. Personall I'm trying to find some 10oz double weave canvas (the waterproff when wet kind) so i can paint it to my liking and using my patent pending no sew joinery (aka contact cement) method. Under the canvas I'll have some shade cloth to block out the light and leave a whole at the top like an igloo to let heat out.

Elemental666 · Post by **Elemental666** » Mon Apr 04, 2005 11:19 pm

oi, just remembered another q I had fer you...

Is the thin wall 3/4" EMT conduit stong enough or do i need to use the rigid kind. I"m hoping the thin wall is ok for a 12' radius as the rigid is a little over $1 a foot...

Thanks

Elemental666 · Post by **Elemental666** » Tue Apr 05, 2005 3:41 am

see if you guys were vampires like me I wouldn't be talking to myself, anyway...

Plan is for a 24' diameter dome, and I got to thinking about ahveing such a long strut with 3/4' emt. Seems a bit flakey as mentioned by someone earlier, too much flex? Anyhow, I can actually afford to get 65 sticks of EMT and was wondering if the 3v wouldn't be more stable?

Then I was thinking about 3/8 or 5/8, am I correct that i could build the 3/8 and if I decide I want the extra height, just add the bottom layer later?

Is a 3v made out of thin wall 3/4" EMT strong enough to hang a hammock from?

Umm, oh yeah, thanks for being so helpful those of you that are experienced!!

robotland · Post by **robotland** » Tue Apr 05, 2005 5:49 am

E6-cubed, I wouldn't use 3/4" EMT to make a strut that was much over five feet long. I can't pull up Tara's Dome Calculator from here but I know the struts for a 2V or 3V that's 12' rad are fairly long- (8' rad. 2V struts are about five feet.) Part of the equation is USAGE- Will you be climbing on it? Will somebody climb on it while you're not looking, or gone? Are you covering it tightly? You're probably going to be all right with a 3V out of 3/4", but you're gonna need more than 65 sticks, my friend. Cheapest EMT in these parts is almost six clams per stick.
3/8 vs. 5/8- YES, go ahead, you can add the other "2/8" later. Heck, you can continue it around to a sphere if you wish. (But rent a crane first. Even a little 6' sphere tries to squash itself!)
YES, you can hang a hammock from it. You can hang TWENTY hammocks from it. BUT ONLY AT THE VERTICES (JUNCTIONS.)!!!!!! Don't put ANY weight on the struts EXCEPT at the points where they connect, or (in a worse-case scenario) it'll fold up on you like a flea market umbrella in a wind tunnel.
Are you deadset on a 12' radius? Here's a suggestion: If this is your first dome, make it a 2V instead....Get a feel for the building and assembly process, and then upgrade to 3V by simply plugging your existing strut lengths into the Reverse Dome Calculator and figuring out which ones you'll need to add that third "V". (I can't guarantee that both lengths in the 2V will be compatable without checking the Calculator- Important to investigate that first! Stupid disabled Java!)
Let me know if I can be of further assistance- I live for this stuff, as others will attest.....

Elemental666 · Post by **Elemental666** » Tue Apr 05, 2005 7:28 am

Yes, pretty much dead set on 12' radius... The dome has a purpose and I want to be able to fit around a dozen or so people comfortably, possible in partitioned areas, along with an altar and a pretty damn big photo. Anyway, I want enough room for the contents and some people so I need the space.

So yeah, a 3v with a C strut of 4.875 + .125 for hubs, comes to just shy of 11' 6" which is perfect. Very little waste (all if can be used in another idea I have) with 3/8, 5/8 produces quite a bit more waist but hey, I can't count the number of times a hunk of 3/4" pipe would have helped me out before...

That gives me the 5' max plus more vertexes, both of which I think will make this a more stable structure and I don't wanna run the risk of it not being up to the job.

While I haven't built a dome before I'm not a stranger to construction. I have experience building houses and all kinds of crazy yard fixtures. Most of my experience is in wood, but i have done some metalwork. I'm not worried about the construction really, I just don't have those tools. Turns out I found 'em pretty cheap and since the only machine shop interested is gonna charge me more than the eq, I'll be doing it myself anyway. Always love getting new tools.

About the hammocks, what if only 1 end was connected to the dome shell. I was thinking of adding a strut to extend into the dome and connect to tree type support with the other hammock hook. Dunno how much since that made, super tired...

thanks for the reply

robotland · Post by **robotland** » Tue Apr 05, 2005 8:21 am

Elemental666 wrote:
About the hammocks, what if only 1 end was connected to the dome shell. I was thinking of adding a strut to extend into the dome and connect to tree type support with the other hammock hook. Dunno how much since that made, super tired...

thanks for the reply

Sounds like you're Locked and Loaded, man.....Hammockwise, you can always anchor whatever the other end is fastened to with a guyline to an opposing vertex or two....I've considered installing a central column to my bottom dome, to fasten tarp bulkheads to- Anchors to the top vertex and a ground spike. You could do an off-center version to attach hammocks to, thuis preserving the center space for your big picture. (Okay-I'm intrigued.)
So: 3V it is....Gonna buy /make a press, or get yerself a hella buff hammer arm? You've got over 300 smashed ends ahead of you.....
Happy Domebuilding! Come by for a trip down the slide, if you're in Hushville!

LemonGod · Post by **LemonGod** » Wed Apr 06, 2005 7:54 pm

Ok, I'm building my first dome this year. It's to be used as communal space for me and about 9 other people. I figure I need a 20ft radius dome to have a decent amount of space. Am I nuts? It seems like many people opt for 12-15ft diameter domes. But that seems small to me for a decent amount of people to hang out in.

V

sputnik · Post by **sputnik** » Wed Apr 06, 2005 8:00 pm

LemonGod

a 20ft radius dome will give you 1200 sq ft of space. This is the size of an average size home. Do you expect everyone to spend all their time in the dome?

LemonGod · Post by **LemonGod** » Wed Apr 06, 2005 8:04 pm

Well that definately gives me some sorta clue. I don't think we [i]need[/i] 1200 sq ft of space.

So now I'll begin figuring out what we do need.

Thanks for the tip!

V

sputnik · Post by **sputnik** » Wed Apr 06, 2005 8:15 pm

LemonGod...simple calculation 3.14 * Radius * Radius

Also, see the links earlier in the thread for the dome calculator.

LemonGod · Post by **LemonGod** » Wed Apr 06, 2005 8:16 pm

Know all about the dome calculator, but thanks for the equation. Damn I forgot more geometry than I thought.

LemonGod · Post by **LemonGod** » Wed Apr 06, 2005 8:27 pm

Wait a minute...wouldn't a 20ft diameter dome be 314 sq ft? (3.14 * 10 * 10)?

I might be confused...

LostMachine · Post by **LostMachine** » Wed Apr 06, 2005 8:37 pm

Lemon you're right.

I think there was some diameter/radius confusion going on. 314 sq feet is about the size of a double car garage.

Last year we built a 30 foot Diameter dome and it was very nice for our 8 people.
Don’t be discouraged build as big as you want.

It is also Fun to build a model first. You can use drinking straws, a long needle, and some thread. Scale your design down, ( i.e. one foot equals 1/2 inch). Having the model will give you a lot of confidence when you go to build the real one.

LemonGod · Post by **LemonGod** » Wed Apr 06, 2005 8:39 pm

I march forward with new found confidence. Thanks all!

LeChatNoir · Post by **LeChatNoir** » Wed Apr 06, 2005 8:51 pm

Area = Pi* (r squared) =
3.1415 * (10'*10') =
3.1415 * 100 =
314.5 square feet.

And remember also:

Circumference=Pi * Diameter

LeChatNoir · Post by **LeChatNoir** » Wed Apr 06, 2005 8:53 pm

Oops... 314.15 square feet.

Elemental666 · Post by **Elemental666** » Wed Apr 06, 2005 9:19 pm

ok you math freaks, riddle me this...

if a 12ft radius dome = 452sq.ft

How much of that 452sq.ft. has at least a 6ft ceiling?

Geodesic Dome Construction (Tips and Tricks)

Try a Pipe Cutter

Re: Try a Pipe Cutter

Try a Pipe Cutter

Am I nuts?