Cardboard Conch Horn




About: The answer is lasers, now, what was the question? If you need help, feel free to contact me. Find me on Reddit, Tumblr and Twitter as @KitemanX

Conch shells make a grand sound as a horn, but several species of the the actual animal are endangered, harmed by being harvested for the souvenir industry.

This is my attempt to create a more sustainable version of the instrument.

Step 1: Materials and Tools

If you know my work, you know I like simple materials.

This is put together from corrugated card from an old box, duct tape, and a short piece of PVC pipe.

The only tools I used were a craft knife, my trusty Leatherman, and a hacksaw (to cut the pipe to length).

Step 2: The Parts

The whole thing is made from the flaps cut from a large cardboard box.

Two flaps duct-taped together made the main coil, and a third flap, cut in half, made the end-pieces.


The flaps were 17cm wide, and when taped together they were just under a metre long.  For the sake of aesthetics, I made the end-pieces 17cm square as well.

The pipe, a scrap I found in a corner, was about 2½cm in diameter, and about 10cm long.

Step 3: Curl It Up

I needed the strip to spiral with ease.

To that end, I used the two flaps which had the corrugations at right-angles to the long dimension.  I dragged the strip hard over the corner of the table to force it into a curl, like quilling, writ large.

Step 4: Fix the Curve

Starting in the middle, I arranged the curled strip into a visually-appealing spiral.  There may be an optimum shape, but I don't know what it is.

I anchored the spiral in place with small pieces of duct tape.  Not pretty, but it worked.

Step 5: The Mouthpiece

The mouthpiece was made from a short piece of PVC pipe.

For comfort's sake, I used my knife to chamfer the edges of the pipe.

I cut a suitable hole in the middle of the second end-piece, and then anchored the mouthpiece in place with more duct tape, then fitted it in place and fixed with... duct tape.

Step 6: Finishing (sort Of), and Moving On.

I taped around the visible edges of the coil with yet more duct tape, and that, really, was that.

All that remained was to find out if it worked...

That's horrible, right?

Things got better, though.  When I showed the horn around the office, one of the suggestions was a proper mouthpiece.  So, I took the horn in to a music shop near where I'm staying, and a very nice assistant let me borrow a mouthpiece for a few moments, and hand the horn to Roger-X, who happens to play the trombone.

The result was dramatic - instead of the hideous noise above, it produced a nice clear "F" (apparently - I am tone deaf, but even I heard that it sounded "nicer").  I would have videoed the nice note, but the very nice assistant seemed nervous about his boss finding out that he was loaning out a $110 mouthpiece to a strange foreigner off the street, so I decided not to.

So, secure in the knowledge that the concept works, I now need to move on to a version that won't turn to mush with use...



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    17 Discussions


    5 years ago

    Hi, looks great, Ill try to build one for my home town parties, using it instead of the hard to find natural shells

    1 reply

    6 years ago on Introduction

    The ideal shape is almost certainly one of these:

    The linear spiral has a constant cross-section so will act like a long tube, the exponential has an exponentially increasing cross section so will act like the bell of a horn (and replicates the proportions of an actual seashell). I made something similar to amplify the rear-facing speaker on my phone so I can hear the speakerphone when it's in the cradle.

    If you find (or make) a couple of sliding-fit cardboard tubes will we see Roger-X playing the cardboard trombone?

    2 replies

    Reply 6 years ago on Introduction

    Right now, I don't *which* spiral I make, I just want to make a spiral.

    (Is there free 3d modelling software that will take pencil scribblings and vague gestures as input?)


    Inkscape will make you a nice spiral. You can then output it to another format like dxf for your CAD prg. Neat shell. It will work better if you can make it a tight seal along the edges of the spiral. No leak means a long tube, and that will play MUCH better.


    Reply 6 years ago on Introduction

    Hmmm, less is more, form follows function, beauty is in the eye of the beholder...


    Reply 6 years ago on Introduction

    There's gotta be a squiggly curve line generator in there somewhere. Then you have to stretch the walls up in 3D along some curving axis. I loaded that up, crashes a lot, and big learning curve. I don't think it is really endeared to artists and turns an enjoyable creative experience into a frustrating one.


    Reply 6 years ago on Introduction

    If there is, I can't find it. Maybe it's not touch-pad friendly, or maybe I just haven't played enough video games...