Giant Straw Tetrahedron Cluster

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Quickly create a beautiful tetrahedron cluster and learn a lot about geometry along the way! This cluster is comprised of 10 individual tetrahedrons connected together. There's no limit to how big you can make the cluster!

Materials:

• Coffee straws (60 needed for the size shown. Try cutting them in half if you don't have many)
• String (You'll want something thin and strong. I'm using jewelry string from the craft store)
• Scissors

Step 1: Creating the Tetrahedron Modules

The cluster I made is comprised of 10 tetrahedron cells. We will start by creating each cell individually and later connect them together. Each tetrahedron is woven together with a single piece of string

• Measure about 4 feet of string. It takes quite a bit of string to weave the seven inch long straws together.
• Thread three straws onto the string
• Grab the two loose ends of string and thread them both through a single new straw.
• Pull the straws together and you should now have a triangle with a line attached.
• Add new straws to each end of the string. You will now have all six straws needed to complete the tetrahedron.
• Grab the end of a string (it doesn't matter which one) and thread it through the furthest straw of the triangle. Please refer to the images if this is confusing.
• Now pull both strings together and your tetrahedron will take shape! Pull the straws together tightly for a precise fit.
• Tie a double knot and trim the excess string

Once you get the hang of it you can make a tetrahedron cell in just about one minute! If you plan on combining them together into a larger cluster you will need at least 4 cells.

Step 2: Assembling the Modules Together

Once you have at least 4 cells you can weave them together to form larger clusters. There is no limit to how many you can connect and what shapes you can create!

• Start by weaving three cells together. Thread a new piece of string through the three edges that connect forming a triangle. Tie a double knot and trim the excess string.
• Continue attaching new cells by weaving string through the connecting triangles. Make sure you attach each point together so your cluster is stable.

Have fun!

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13 Discussions

Thanks for your time creating this instructable. Very useful.

I have made these before. It is amazing how sturdy they are for being made of flimsy plastic straws.

5 replies

Hot glue sounds like a better medium then string, if done carefully!

The string worked really well for me. I was considering hot glue myself but after the string proved so sturdy I never ever bothered. In the end it seemed that any type of glue would make the structure look messy, whereas the string is completely hidden and the structure looks cleaner as a result.

Yes. I used hot-melt glue, but it would melt the straws, so I used bamboo skewers, cut in half , a soldering stand helps hold the three-splint cluster together while you glue the third... I added some photos , above.

Yes the straws are in "almost pure" compressive loading, i.e. the load in the straws is on and along the axis of the straw.

If we had a better "purer" connection where the straws join Then we could allow for axial tensile forces as well. The tetrahedron, based on the geometrically pure, loading pure, triangle would then be complete.

I made mine a flat panel (albeit six sided), and there's no problem with stacking books on top of it. Holds more weight than you would imagine. Build one and see!

Love this! So minimalistic...beautiful(and made from straws!)

Using this technique and some thin film you will end up with an awesome kite!

I made one. 4ft tall, I forget how many cells. I made it with clear straws and clear cheap (thin) trash bags. It was fun when someone walked up, looked up and wondered 'where is that string going?'

One filmed with space blankets and lit with LEDs could be cool.

great stuff, though a certain Leo thingy Davinci came up with this with a few years ago,

now take any 3 cell multiples and cover 2 sides with paper or for invisibility use cling film! attach a flying line and you have an amazing kite.

Another, super easy method of joining straws is to use another straw. Crease along the long axis and then fold in half along the short. Insert into two adjacent straws. Each open straw end can accept two folded straw connectors, which provides enough friction to hold them together. Easy, and easy to reconfigure. I've made icosahedrons, dodecahedrons, and hypercubes this way.

If you cut straws in half, you have to take care that they are in half. Very little slop translates into a unsightly gaps.

If you want to go bigger:

* Soda straws.

* Tubular plastic garden stakes. (about 3 feet long) Haven't seen them since I was a kid.

* Electrical conduit, either metal or plastic, copper pipe, CPVC plastic pipe, all come in 10 foot lengths.

Connecting: For small ones in addition to the mentioned jewelry cord:

* fishing line. (braided line will tie better)

* Dental floss. (Unwaxed is easier to work with.

Larger ones:

Builder's cord (1/16" braided nylon cord)

Aircraft cable (Often cheaper than nylon rope.) You can't tie it, but have to use cable clamps, aluminum crimping sleaves, for fake it and or use small diameter copper pipe as crimping sleeves.

It would be fun to do out of thin translucent straws, and run those LEDs on a wire through them.

That's a slick trick, threading cordage through the straws, to (snicker) tie your tetrahedrons together. Trying to accurately position straws or sticks together, & then glue or tape them in place is a royal pain in the phatoot. This would be great for making tetrahedron kite frames. Good instructable.