Geodesic Dome for Idiopolis

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

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.

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 (L, purple in construction diagrams)
40x 15cm tubes (M, red)
30x 13cm tubes (S, blue)

Dome construction

-Things to remember:-

The dome only consists of two types of triangle - LLM and MSS. If you ever construct any that don't match these, something has gone wrong.
All six 5-way hubs can be populated with M pipes before further assembly
Similarly, 5 6-way hubs can be populated with only L pipes.
M struts never occur next to each other on any single hub.

Start with a 5-way connector and put 5 S tubes around it. Tip these with 6-way connectors, and connect them with 5 M's to form five MSS triangles.
Add two L tubes to each of the outlying 6-ways leaving the last connection free. Connect these at the ends into five LLM triangles with more 6-way connectors.
Fill up that last space with M tubes, and end those with 6-way connectors. Join all the outlying 6-way connectors up with more A tubes to make 10 more LLM triangles.
Any 6-way with just L pipes to it, add two more L pipes. Any others, put two M pipes around it leaving the centre free.
Make 5 more 5-way connectors with all the remaining S-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 LLM and 10 MSS triangles.
Connect the new 6-way connectors from above with an M-pipe. This will lift the dome a lot.
Fill up the remaining spaces on the 6-way connectors with only L's and M's by making sure that a M-pipe is never next to another M-pipe.
Join the ends of the new M's and S's with 4-way connectors, and L's and L's with 4-way connectors, forming 5 LLM and 10 MSS triangles.
Join the remaining spaces up, connecting two MSS triangles with an M-pipe, and everything else with an L-pipe in an L-L-M pattern as you go around. Initially this will put a lot of stress on the freshly made joints, so on large scale make sure you have someone to help lift the dome with you as you complete.

Construction of midi dome

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 'S' : 0.70m x 16mm PVC
40 x 'M' : 0.80m x 16mm PVC
50 x 'L' : 0.82m x 16mm PVC

We will need 24 4m x 16mm PVC pipes + 1 extra = 25 pipes. Cut them as follows:

13 x SMLLL
9 x SMMML
1 x SSSLL
1 x SSSSS

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 (300x)

Construction of Maxi (9m) dome

All maxidome related info has been moved here

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

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