Syringe Slide Whistle




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.

Syringes are almost ready-made slide whistles.  The sliding plunger makes a good seal and slides easily.  All they need is a sounding hole and an air channel for blowing against the sounding hole. 

The plastic needle cap only needs slight modification to become an air channel. 

Cutting the sounding hole is easily done with a sharp X-acto knife. 

For those who are shocked by drug use associations with syringes, think of cannons to plowshares, or doctors who save lives.  Better yet, just think of them as plastic tubing. 

Be sure to check out the MP3 sound file in the last step to hear how the slide whistle sounds.   This is a fine little musical instrument that only costs 25 cents to make. 

Step 1: Remove the Needles

The first step is to remove the needles.  Do this carefully to avoid getting poked.  They are surprisingly sharp. 

The protective caps pull straight off, and the needle twists off.  Pull the cap slightly off, to free it, but use it to grab and untwist the needle from the end of the syringe.  When you get the needle free it can easily be removed from the cap and placed in a secure container for storage or disposal. 

I still haven't found a good use for the needles, but I hate to throw them away.  It amazes me how they can make such tiny metal tubes in the first place!  I could never make them myself. 

Step 2: Cut Off the Ends of the Needle Caps

Use a very sharp knife to cut off the closed ends of the needle caps.   Instead of a straight guillotine cut, I use a forward slicing motion with the knife.  The plastic is fairly soft, but might crack under pressure with a guillotine cut.

When you are done, the caps are open-ended tubes. 

As far as I can tell, both the syringe bodies and the needle caps are made of polyethylene plastic.  The cap tubes will later be heated and press fitted to the syringe bodies.  I am finding that different syringe manufacturers sometimes make slight modifications in their designs.  If the syringes you get have needle caps of a different kind of plastic, you may have to shape them by some means other than heating.   Let's hope you are lucky and they, too, are made of polyethylene plastic. 

Step 3: Cutting the Sounding Hole

The sounding hole is made with two cuts with the X-acto knife.  I put a tight fitting dowel inside the syringe body to help hold it for these two cuts.  I do the diagonal cut with the syringe horizontal on a table.  I do the second cut with the syringe held vertically on the dowel in a vise, so I cut pressing straight down on the knife. 

Having the dowel inside on the first cut helps keep yourself from accidentally cutting down too far. 

After the two basic cuts, I dress the hole up as needed with the tip of the X-acto knife. 

Step 4: Heating and Placing the Air Channel Tube

This step is a little tricky.  Without a propane torch, you might be able to do the heating with a cigarette lighter, because it doesn't take a lot of heat. 

Heat the tip of the air channel tube on the bottom side only, where it will press against and conform to the shape of the end of the syringe.  This takes a little practice to get consistently good at it.  It is better to not heat it enough and have a second try than to butcher it with too much heat the first time.  I was lucky, and had 40 successes out of 40. 

Carefully soften the plastic and press the tube down where it belongs on the syringe body.  Aim for the angle you see in the photos, and placement at the beginning of the sounding hole.

I used sections of electrical tape cut in half lengthwise to tape the air channels to the syringe bodies. 

Step 5: Hear the Slide Whistle

Click on the icon below, that looks like a piece of paper with the corner bent over, to open an MP3 audio file and hear the slide whistle. 

Low notes are with the plunger all the way down.  High notes are with the plunger closer to the sounding hole.  Between the two extremes, there are an infinite number of notes.  Have fun finding the ones you are after! 



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    10 Discussions


    3 years ago

    You can always donate the needles to Cartridge World!!! We always need them!!


    6 years ago on Introduction

    Do you make the needle cap air tight over sound hole? looking at picture cap doesn't completely cover sound hole so you use tape to make air tight? You blow through that same cap letting air exit the hole where needle originally sat? sorry for all questions. Thanks much for sharing this.

    3 replies

    Reply 6 years ago on Introduction

    If you have ever seen a recorder mouthpiece, it has an air channel (the needle cap in this case) that directs the air you blow at sort of a wedge that divides the air. Some of the air goes through the body of the whistle, or flute, and some exits there at the sounding hole to outside the body. So, no, it doesn't completely cover the sound hole. The tape was used just because most glues don't stick well to that kind of plastic (polyethylene). Like blowing over a bottle to make a hoot, you have to control the flow of air and direct it where needed. That's all the needle cap does, act like plastic tubing.

    The sounding hole is the hole cut in the side of the syringe barrel and given a wedge to part the air.


    Reply 6 years ago on Introduction

    Did a little 1/2 cc microfine to test and works haha. Cool now will try other sizes. Thanks again, something I can do with my grand kids haha.


    Reply 6 years ago on Introduction

    K, cool thanks I have a couple recorders so understand. Cutting up the syringe now. Thanks again appreciate your help much.


    6 years ago on Introduction

    Kinda like a trombone slide? I will try. I have all types of syringes. Thanks good idea.

    I don't doubt that you can find them, but I doubt that I can ... at least not locally. This is backwoods Puerto Rico. Maybe an idea will come to me eventually for them. Voodoo dolls?


    Reply 8 years ago on Introduction

    They are a little tricky, but it only takes slight movement to jump to different notes. It takes a little practice, but much less than a fiddle.