Styrofoam Harps




About: I'm a refugee from Los Angeles, living in backwoods Puerto Rico for about 35 years now and loving it. I built my own home from discarded nylon fishnet and cement.

Professional harps are cool instruments, but expensive and difficult to play.   These may be toy instruments, but they still sound nice and have possible uses in the creation of music.  With maracas and drums I could imagine some fun jamming with these. 

The instruments are feather weight.   I don't know how child-proof they might be, but I am tempted to find out.  I think these would be great learning tools for introducing children to string instruments. 

All four sides of the harps can be played.  Each side has a slightly varied selection of notes.  The strings are not tunable, but there is a general progression from low to high notes.  

Be sure to listen to the .mp3 audio file in the last step to hear how they sound. 

Step 1: Shaping the Foam

I made two harps with differences in length.  The long one uses only mono-filament nylon fish line, which is next to invisible in the photos.  The short one alternates fish line with rubber bands.  The rubber bands give the notes interesting overtones. 

The harps are basically Styrofoam triangles cut out of a thick sheet of the material.    That gives a variety of string lengths, and a variety of notes.  The longer strings make lower notes. 

The strings make contact with the body only on the edges, which are protected by half-pipes of 1/2 " CPVC pipe (smallest size for hot water use).  On the face of each side, between the pipes, I hollowed out the foam some, to give the strings more clearance for movement.  If the strings touch anything while they vibrate, it results in a buzzing sound. 

Step 2: The Nail String Guides

1 1/2" nails are driven through slightly tight holes in the pipe edge protectors into the Styrofoam block.  Leave the heads sticking up some, as they are used to anchor the fish line that spirals around the instrument. 

If you plan to alternate rows of fish line and rubber bands, make sure you don't get carried away and wrap fish line where the rubber bands go, too.  If strings touch while vibrating, the resulting sound is not as clean. 

I wrapped the fish line by hand, stretching it as tight as I could.  It may stretch and get lower in tone over time, eventually needing re-stringing.  Fish line is cheap.

Step 3: Stretching the Fish Line

Start at one end and spiral wrap the instrument with a continuous length of fish line.  Since the line only wraps twice around each nail, and is not tied firmly, I imagine that there will be some slippage of the line throughout its length as the instrument is played, resulting in approximately equal tension on each string.  Then, the differences in length should provide the progression of notes. 

When you wrap the fish line, wrap it as tightly as you can by hand.  Do not release tension with your hands until you reach the end and have it tied off securely.  If it slips before tie-off, you may have to go back and wind it all over again from the beginning to regain the tension. 

I used two slits cut in the ends of the corner protectors to begin and end the line winding.  The slits help hold the line tension while I tied the knots.

Step 4: Hear the Harps

Click on the thumbnail icon below to open an .mp3 audio file and hear how the harps sound.  The icon looks like a blank piece of paper with the corner folded over. 

I hope you enjoy this cheap, but pleasant sounding instrument.   It's fun to play. 



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    12 Discussions


    Reply 3 years ago

    These experiments were long ago. I would guess the long harp was two or three feet long. You could look at the size of the beads, guess the thickness (which comes in different inch sizes) and then guess the other dimensions. Just try it out with some scraps. Any size could work.

    A friend once had a styrofoam flat panel speaker in the rear deck of his baby blue GTO I'm remembering the acustic properties of that speaker and of course the ride and the eight track music a foam speaker sounds novel but
    its also good insulation. best sounding speakers i ever heard were in mahagoney boxes with foam insulation its resonance sound is warm like the foam the mahagoney was pourous and yet resonance

    You can hold up a block of styrofoam to your ear, place a small radio on the other end, a LOOOONG way away, and hear the sound *very* clearly from you end, perhaps even louder than if you were near the source. I have read that this was tried with a piece of foam several blocks long, and worked! Try it!

    You may find inspiration at a conglomeration of creative musicians/inventors that have done this to the utmost. And the results are often stunning. Fun stuff! Thanks for the instructable.


    8 years ago on Introduction

    Styrofoam is an interesting choice for a harp, light and strong. But, aren't acoutsical instruments supposed to be hollow to better amplify the sound?

    I like your new projects on styrofoam instruments, what's next?

    2 replies

    I don't understand why solid Styrofoam works as well as it does. Perhaps it is so mass-less it is almost like being hollow. It vibrates with little energy because it weighs so little.

    I don't know what's next with the Styrofoam. I'm working on hollow rubber wind instruments at the moment. Not a whole lot of success thus far.


    8 years ago on Introduction

    I love this ible! BB King first learned to play using a single strand of wire from a broom that he hung from a nail on the porch! I love the simplicity and the sounds pretty good too. Great job.

    1 reply