Spaghetti and Glue as Building

Materials

David Dobson, Electrical Engineer, USQ

graduate and 3rd place in the 2013 Thiess

Spaghetti Bridge Competition, RME

How Spaghetti was chosen

• Purchased all available

spaghetti- differing

brands and sizes

• Stress test

– Horizontal load

– Vertical load

• Compression

• Tension

• Weight held ---------------

-------- Weight of 10

strands (equal length)

Choice of Glue

• PVA

– Slow drying

– Strong bond

– Fill voids

• Hot Glue

– Fast drying

– Weak bond

– Fill voids

• Superglue

– Fast setting

– Strong bond-low shear

– No voids

Behavior under tension

• Badly

• Brittle

• Not predictable

Necessary to build a prototype?

• YES

• Partial build of main

features

• Test out Glue

• Test out spaghetti

choices

Management of brittleness

• Design

• Tried to reduce amount

of tension

– More spaghetti under

tension than

compression

– Shared between more

strands

• Keep straight

– Direct forces

– Reduce/remove bending

forces (shear?)

• Shorter multiple pieces

under tension

Spaghetti inspection

• Flaws or imperfections

in spaghetti

– Cracking

• Longitudinal

• Lateral

– Necking- Narrowing

– Curvature

– Discolouration

– Contaminates

• Is derived from raw

materials – expect

contaminates.

Troubleshooting

• Spaghetti shrinks when

dried.

• Don’t let dry unevenly

• Use spaghetti from

same packet

• Store spaghetti with

bridge

• Atmospheric conditions

make a difference

Troubleshooting

• Ensure feet of bridge

seated if rigid structure

• Don’t use excess glue

Formers

• Good in theory

– Glue sticks

What to do with excess spaghetti?

David Dobson

David.j.dobson@me.com

References

• http://pages.jh.edu/~virtlab/bridge/truss.htm

• http://jeramypaxton.com/2013/05/project-rc-kite-initial-testing/

• http://www.lloyd-instruments.co.uk/Accessories/Food-

texture/Pasta-Rice.aspx

• http://en.wikipedia.org/wiki/Cyanoacrylate

• http://ilovebacteria.com/spaghetti.htm

• http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.95.09

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