Geodome

Geodesic Dome for Idiopolis
Participants
Skills	Mechanics, Muscles, Pipe Cutting
Status	Active
Niche	Hardware
Purpose	Infrastructure
Tool	No
Location
Cost
Tool category

Geodesic Dome for Idiopolis

Dome Construction 9.jpg {{#if:No | [[Tool Owner::{{{ProjectParticipants}}} | }} {{#if:No | [[Tool Cost:: | }}

Introduction

As Idiopolis, we have this super cool army tent at our disposal, but it's getting a bit flimsy, and it is not entirely sure how long it will survive. On top of that, all our party tent have been frankensteined into a mother of all partytents at haxogreen, but unfortunatly it has met its demise at the hand of the weather gods. I believe this provides us with ample arguments to consider a new construction for idiopolis, after all, CCC camp is just around the corner.

Proposition

I propose to build a geodesic dome to house our chaotic village in.

<insert cool geodesic dome pics here>

Pros:

• Strong construction due to its nature
• Durable
• Broken parts are easily replaced
• Spacious
• Could be used as place for giving lectures/talks/open discussions
• And kinda cool
• Few different kind of parts

Cons:

• Lot of parts
• Possibly heavy
• Possibly bulky
• Lengthy construction time

Construction of the pipe cleaner connectors

Start with two pipe cleaners, crossed in the middle.

Fold them across each other. For a 4-way connector (blue hubs in the construction diagrams), do this again and stop here.

Add a third pipe cleaner across the fold to form a crude hexagonal arrangement. For a 5-way connector, offset the lengths so one is shorter than the others.

Counting from the top clockwise, fold the first(2 o'clock) and fifth(10 o'clock) spokes around the sixth (12 o'clock). Do the same for the the second(4 o'clock) and fourth(7 o'clock) spokes around the fourth (6 o'clock).

Rotate the entire structure clockwise by one spoke.

As above, fold the first(2 o'clock) and fifth(10 o'clock) spokes around the sixth (12 o'clock) in the opposite direction to before. Finally, fold the second(4 o'clock) and fourth(7 o'clock) spokes around the fourth (6 o'clock) in reverse again to produce a 6-way connector (white hubs). For a 5-way connector (red hubs), loop the short end around the core and trim it short.

Construction of full scale ziptie hub prototype

Take 75mm ring with 24mm drilled holes, 40mm inner hub ring, strut and ziptie.

Ziptie ring in 8mm drilled holes.

Continue as above.

Make sure to leave ~5mm on the ziptie when cutting short so the catch cannot slip so easily.

Minidome strut construction

Cut:

• 50x 15.5cm tubes (A, purple in construction diagrams)
• 40x 15cm tubes (B, red)
• 30x 13cm tubes (C, blue)

Dome construction

-Things to remember:-

• The dome only consists of two types of triangle - AAB and BCC. If you ever construct any that don't match these, something has gone wrong.
• Whilst there are 6-way hubs with only A's and 5-way hubs with only C's, B struts never occur next to each other on any single hub.

Start with a 5-way connector and put 5 C tubes around it. Tip these with 6-way connectors, and connect them with 5 B's to form five BCC triangles.

Add two A tubes to each of the outlying 6-ways leaving the last connection free. Connect these at the ends into five AAB triangles with more 6-way connectors.

Fill up that last space with B tubes, and end those with 6-way connectors. Join all the outlying 6-way connectors up with more A tubes to make 10 more AAB triangles.

Any 6-way with just A pipes to it, add two more A pipes. Any others, put two B pipes around it leaving the centre free.

Make 5 more 5-way connectors with all the remaining C-tubes and put one joining to the remaining spaces where the B-tubes join. Then use more 6-way connectors to join up the next outer pair and form 10 more AAB and 10 BCC triangles.

Connect the new 6-way connectors from above with a B-pipe. This will lift the dome a lot.

Fill up the remaining spaces on the 6-way connectors with only A's and B's by making sure that a B-pipe is never next to another B-pipe.

Join the ends of the new B's and C's with 4-way connectors, and A's and A's with 4-way connectors, forming 5 AAB and 10 BCC triangles.

Join the remaining spaces up, connecting two BCC triangles with a B-pipe, and everything else with an A-pipe in an A-A-B pattern as you go around. Initially this will put a lot of stress on the freskly made joints, so on large scale make sure you have someone to help lift the dome with you as you complete.

Covering

I have prototyped a theoretical covering for the above structure consisting of hexagons and pentagons of 18cm side length. There seems to be enough slack with this ~20% extra space to allow for the centre dimpling of each polygon. On large scale this covering will need tying down somehow - I'd recommend constructing tiedowns on the triangular face joints. This ought to allow sufficient strengthening, and is possible to tie on if the above construction method is used, by constructing the whole thing underneath the covering.

Todo

Construction of 4m prototype

Required materials:

• 30 x 'A' : 0.7m x 0.15 PVC
• 40 x 'B' : 0.8m x 0.15 PVC
• 50 x 'C' : 0.82m x 0.15 PVC

We will need 24 4m x 0.15cm PVC pipes + 1 extra = 25 pipes. Cut them as follows:

• 13 x ABCCC
• 9 x ABBBC
• 1 x AAACC
• 1 x AAAAA

• 25 x 6-way connectors
• 6 x 5-way connectors
• 15 x 4-way connectors

Total = 46 connectors. A connector consists of an inner ring and an outer ring. The inner ring is a 40x20mm PVC ring. The outer ring is a 75x35mm PVC ring.

• 46 * 20 = 0.8m tube to make the inner rings
• 46 * 35 = 1.61m tube to make the outer rings.

PVC shopping list
25 x 4m x 16mm pipe
1 x 1m x 40mm pipe
1 x 2m x 75mm pipe

Bag of zipties

Construction of 10m dome

• Enumerate required tools

10x 8mm drills to drill the holes in the tubes
24mm speed drill to drill this holes in the outer hub ring
Hacksaw to cut the PVC tubes in outer hub rings
Grinder to cut a 40mm steel pipe into inner rings

• Acquire missing tools needed
• Settle on size
• Settle on tube diameter
• Settle on hub design
• Determine total length of tubing required
• Find supply of steel tubing
• Design hubcap
• Print hubcaps
• Purchase materials
• Cut tubes to required lengths
• Build linkage
• Create assembly plan
• Assemble in back yard

Covering

• Request a sample of hermetix from supplier
• Validate Hermetix as viable covering candidate.
• Decide on covering material
• Determine how many hexagons and pentagons are needed
• Calculate appropriate sizes for hex and pents.
• Find supply of covering material
• Extract required shapes from material
• Decide on how to bind the shapes together
• Create cool showoffy idiopolis artsy design for covering
• Find the appropriate rivets to mount in the cover in order to rope the covering down
• Find a method to cut holes in the fabric in order the mount the rivets

A rough estimate based on a 10m dia dome, yields 256m2 of covering
A request for a 1m2 sample has been sent out on 22-4

Transport

• Determine dimensions of a case or cases in which the dome can be transported
• Create a design for said case(s)
• Build case(s)
• Find someone with a van/trailer/bus to transport the dome to germany

Design decisions

• The dome will be 9.6m in diameter
• The tubes will be 22m steel tubes
• The inner ring of the hub will be a 40mm external diameter steel ring, with a height of 25 mm.
• The outer ring of the hub will be a 75mm external diameter PVC ring, with a height of 50mm.
• Both ends of a steel pipe will be equipped with a 8mm hole, with it's centerpoint located 8mm from the edge.
• The outer hub will be equipped with 24mm holes.

Ideas

• Connector construction: [[1]]

• Using steel CV pipe rather than PVC (heavier, but cheaper and stronger)
• Using Hermetix as cover. E137,60 for a 50m * 8m roll

Useful links

http://www.cvtotaal.nl/cv-buis-22mm?utm_source=google&utm_medium=organic&utm_term=&utm_campaign=shopping&gclid=COWu88r5gsUCFcuWtAodl2IAuA

http://www.dekzeilenshop.be/nl-content1.asp http://www.deboerdrachten.nl/landbouwplastic-landbouwfolie/4682013/Landbouwplastic-Hermetix-50-x-8-meter-wit-groen/