Building a geodesic dome

Hi all!

Apologies for radio silence! Internet is awful in East Mayo.

So I made the plans, figured out the bevel degree I needed and am going at a very slow and steady pace (I want this to last for the shutdown!

I'm using 2x1 timber, and it should have a diameter of just under 4 metres.

I made one prototype pentagon, and am not 100% happy with it as the wood was so wet, the screws that went into the grain didn't hold.

One of the problems I had was the 2" edge of the timber, as my table saw wouldn't cut through all the way along the bevel, so I trimmed them down to 45mm and it was fine.

I decided to cut down the 4.8mtr lengths down to near enough size (leaving at least an inch over for shrinkage) as they would be easier to stack and air.

I know it'll take a long time to dry them properly (especially in Mayo weather!) but with them being treated already, I hope they'll be good enough to hold a screw in in about a weeks time!

I ordered a digital inclinometer which should arrive next week, so I can fine tune the angles on my table saw and chop saw for the cutting angles I need.

As for now, I'm learning sketchup, as I would love to get into 3D design and this is a pretty easy (but advanced for a beginner) project to design. I tried doing it last week, but the rotate tool was the devil and I couldn't get it to piece together properly.

Thanks for all the input, love the cardboard dome!

Double Barrel wrote: »

On a budget or not , why not consider a wood preserver such as Protim E, Barrettine Premier, Cuprinol Ducksback, Osmo, Sika and/or Ronseal Total etc.
Solvent based or Water based your choice.
Apply to framing members before assembly and let it dry and off gas and you will be ready to frame.

Yep. I am definitely going to stick some wood preserver on, once all the wood is cut

cletus wrote: »

No problem, tone can be hard to communicate via text.

The second part of my post was directed at the OP. I'm not even sure you could buy the joints even if you wanted to.

As an aside, could your design be altered to allow for 2x1 to be attached instead of the cardboard tubes

I'm constructing without hubs or struts, so should look like this:

Have to say, the wood is drying nicely. Not doing anything more until the inclinometer arrives.

So today, made the daughter a swing. She's only delighted with it.

I'll be honest, the aesthetic was first for me. They look awfully pretty. After that the wind resistance is pretty good, it'll be in an exposed area, and the wind buffeting off a solid wall wasn't something I liked the sound of.

The individually wrapped triangles has a better aesthetic, it's apparently easier to apply heated plastic over it. As for leaks, I purchased poly weather proof tape, so will be putting that on the outside.
I'm taking a lot of inspiration came from geodome.co.uk who was kind enough to send me old plans that I altered.
And the triangles being individually wrapped came from: https://astriddegroot.wordpress.com/2011/01/16/dome-greenhouse/

I really hate baggy plastic in greenhouses...

All my wood has now been trimmed down to 44mm thickness, so even though the sun is shining, I have some real work to do, so will leave the bevelling until tomorrow.

My inclinometer arrived today, and it is great. I have no idea how you would make one of these without one.

Link here: https://www.amazon.co.uk/gp/aw/d/B07D8TJF4P?psc=1&ref=ppx_pop_mob_b_asin_title

Sorry for lack of updates, had some real work and family stuff...

Anyway, basic structure complete. Just have to make the door, frame and put a window in and then cover each triangle with plastic.

I covered it with black plastic tonight, as there's rain due soon. Glad to say it's sturdy enough for me to swing out of those tiny beams!

mobfromcork wrote: »

Good to hear it's going well. Would love to see a few pictures when you get a chance. Did you make the frame to fit around the window or get a window to fit the frame?

I'll have to sort out some more pics alright.

I'll take out the equalateral triangle opposite where the door is going and make a window to fit that. I'll fit the window with some old pivot hinges I found.

mobfromcork wrote: »

Hi Pappa Dolla, did you cover your Dome yet? Happy with the covering from Polyrope?
Any pros/cons that you found for covering one triangle at a time? Still in the planning stage here but need to order timber for another project as well.
I made up a polytunnel last week from two old trampoline frames so might get that covered while I get going on making the dome.
Mark

Hey Mark,

Yep, it's up! I'm very happy with the poly from polyrope. It's not as clear as I thought it would be, but it retains the heat well!

Pros: it's beautifully stretched. I also applied it with heat, sing an old plug in flat radiator on its back.
If something smashes through the plastic, I can just take out one triangle and recover it.

Cons: I suppose the biggest is it takes more time. I think I got it down to about 8/9 minutes a triangle, something like that.
There's also probably more waste as you can't really tessellate odd shaped triangles.

We had a bit of a storm last weekend with gusts of 110km. To say my nerves were gone would be an understatement!

I don't know if I mentioned it, but the MIL wanted this temporary, in case she didn't like it, so it's built on u levelled ground with no foundations!

Hearing of the storm the previous Monday, I ordered 1 mtr lengths of 10mm threaded bar. They arrived Wednesday. I drilled a 12mm hole into the bottom planks, and pushed down the bars. I only did this on 3 of them, 2 by the door and one opposite. All was well the day of the storm, but when the wind died down, I rn in to see if there was any movement, and while I was in a huge gust blew open the door (minor fix required) and tried to lift it off the ground. That was terrifying!

As I haven't made this to any plan, I'm still working (battling) with triangular windows, trying to source autovents that will work on a triangular window and figure out the door, which I'm not happy with at the moment.

There's definitely worse ways to spend lockdown, and I have a couple of people interested in buying one if I make any more.

I'm moving into a house with a workshop over the next few weeks, and will make up 2 (I think it'll take as long to make 2 as it does one when it comes to setting up jigs, beveling wood etc). One for us to grow in, and one for us to try and sell. The one I made here is in the front garden, and you can hear the cars slowing down to get a good look at it.



And in Party Mode:

mobfromcork wrote: »

Thanks very much for replying. It looks absolutely class!
Good to hear the covering went ok. After you did each individual triangle how did you attach them to each other?
Did you seal between each triangle externally? Any thoughts on the dimensions of the timber you used? Will you change anything for the next two do you reckon?
Being inside as it's being lifted up by the wind doesn't sound like a barrel of laughs! I'll have to figure a way to secure mine(when I make it) to the ground quite securely. The idea of a bar sounds good, mine should be permanentish so might bury the end of it in concrete.

Thanks again

Cheers!

Each triangle was screwed together (countersunk first) generally about 5 or 6 screws in each side.

As an aside do not even attempt it without clamps like these:



I started without them, and it was a massive pain in the hole.

After it was assembled I used poly tape down the seams on the outside to stop water getting in.

I used 2*1 and will use it again, I like the look and it's strong enough. I'd need a bigger table saw if I was to go bigger as well.

My next plan is to move it, build a 6" deep trench, 9" wide, put threaded bar, into 3*2's and plant in the trench. Fill the trench with gravel, make a 10 sided shape from 2*2, with the metal bars going through that. Place the dome on top of that, and bolt it in place. Load of hassle tbh, and a mistake I won't make next time. Ground prep will be done before assembly.

The loose gravel is for drainage. There's no way there won't be a marsh around the perimeter with rain and nowhere else for the water to go. Concrete may have you the same problem. Best of luck with it. This was a fun project, but I'm really looking forward to my next two.

SouthWesterly wrote: »

Looks a great job. My wife is "encouraging" me, forcefully, to get one.

Can you give us some idea of your materials list and cost?

As parts of it were cobbled together, I don't have an exhaustive list, but this was a 4mtr dome, with 60cm pony wall. Overall I would imagine it would come to about 400 quid. I'll know more next time, as I have to order everything.

GinSoaked wrote: »

Can you say how many feet of 2 x 1 you use then I'll see what the trade (cash) price is at the local timber yard.

For the dome and not the upstand from the list for the kit that would be 30 short and 35 long lengths so really only need the lenghts of the short and the long section x2 because you are making up individual triangles . The timber yard does 2 x1 timber in 16 ft lengths (less the usual bit for nominal lengths) so I can work it out making max use of the timber.

Edit - in italics

I used the calculator at http://geo-dome.co.uk/2v_tool.asp. if you're using hub and strut, you'll use a lot less material than I did