Making a Fully Welded Geodesic Sphere




Introduction: Making a Fully Welded Geodesic Sphere

Just a quick and dirty instructable to show the process I used to make a fully welded geodesic sphere!

To begin with, full credit goes to this instructable ( ) by Nicolas Jara for inspiring me to build my own but using a slightly different method. :)

The structure is buit out of TIG welded 2mm TIG welding rods. The rods are made of steel and are just plated with copper.

You might have been tricked into thinking that the sphere is rather big by the first picture but it's actuallly only 40cm in diameter.

Step 1: Preparing Your Struts

I used the very nice online calculator provided by Desert Domes ( ) to determine the legths of my "struts" .

I decided to go with a 2V sphere to limit the suffering but still end up with something that somewhat resembles a sphere!

So I bundled up 30 TIG welding rods by wrapping some tape around them before cutting them to the right length (given by the calculator).

So after just 4 cuts I had all of my 120 struts (60 of length A and 60 of length B) ready to get into my jig!

Step 2: Getting Jigged Up

Now, what I did is very likely not the most time-effective or the most precise method of doing it but it ended up working OK so here it goes:

I threw together a little jig to be able to weld 12 identical "pentagonal pyramids" with a base composed of 5 struts of length A (the longer struts) and the 5 edges composed of struts of length (you guessed it........) B!
The edges meet at the centered vertex.

The pictures speak for themselves, the base is shaped out thanks to 5 lengths of square tubing (hot glued to the working surface) and the edges are supported and guided by a central elevated plug which has 5 little slots that the struts can sit in to get the angles equal!

Step 3: Welding the Pentagonal Pyramids

I set up my tig welder to a low amperage (about 10-15 amps) and started by welding the vertices at the base before closing it all up by welding the upper vertex.

My welds are kind of sloppy and probably really weak but it all held up fine in the end!

Once I had my 12 pentagonal pyramids the fun and exciting part could begin

Step 4: Temporary Hot Glue Assembly Followed by Welding

Now was the part where I asked myself how to get the sphere to close up nicely without having to be insanely precise with angles an lengths and having to do a lot more jigging.

The solution I came up with was to TEMPORARILY assemble everything with hot glue and once the sphere was complete, to use a blow thorch and remove a SINGLE ugly blob of hot glue before immediately replacing it with a beautiful weld. And to keep on going until all of the glue is replaced by welds.

If you guys know of another way of dong this (without using connectors obviously) , I'm interested ;)

Step 5: Go Play Soccer With It!

Or make it into a super cool lamp shade or a funky disco ball, be creative!

Feel free to ask questions if you have any! ;)

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    4 Discussions


    Question 2 months ago on Introduction

    Can you share how did you determined the height of your jig center post? I am welding 4" lengths and a test with wooden sticks looks like approx 2.5" is a good height. But wanted to know if there was a magic formula. Thank you in advance!

    Gael - Tim
    Gael - Tim

    Reply 2 months ago

    I just played around with the height until all the struts met at the center/ vertex. There most certainly is a formula but I just eyeballed ;)


    Question 1 year ago on Step 5

    Great post, very neat idea to use the hot glue for assembly
    Do you think solder might work instead of tig weld seeing as the row are copper coated and should solder ok?

    Nicolas Jara
    Nicolas Jara

    3 years ago

    Thanks for the credit!

    Your sphere looks great, and it's a very clever construction method, specially the hot glue. Actually I had to deal with all that moving little rods when soldering two pentagons together.