The Magic Whistle

One of the first things I printed on the RepRaster 5000 was a whistle, you know, in case there was an emergency soccer game or something. To my amazement I took it off the bed and blew into it and it worked! I had just printed a fully functional whistle, and thusly declared The Future™ to be here.

Whistle #1 was a little rough. It worked, but it didn’t look very beautiful. (Well, beautiful by 3D printing with plastic filament standards.) After some tweaking and calibrating I printed Whistle #2 and it sounded just like Whistle #1 but looked a little better. An improvement!

That brings us to Whistle #3. As any good RepRapper knows, you can’t just leave well enough alone, and if you’re happy with your slicing settings, you’re doing something wrong. With this in mind I set about changing all the numbers in Slic3r and then attempted to print another whistle.

When I popped Whistle #3 off the bed and blew into it… nothing. Well, not nothing, just the sound of air, minus the sweet whistling sound. I recently told my kids that failure is just a part of the learning process, so I wasn’t ready to quit.

I got a knife and made sure to cut out any stray filament from the bridging during printing. Still no go. I decided to rinse the whistle out thinking maybe there were bits of plastic inside. (Yeah, at this point I was just grasping.) Lo and behold, with the water inside my whistle totally worked! There’s a fine line between science and magic, and I’ll get to that in a minute.

I’m no Whistlologist, but my first guess was that the volume of air inside the whistle was too much and preventing it from operating properly, perhaps due to the lower infill I used when printing. I ended up being totally wrong about this. It had nothing to do with the volume of air (duh!) but everything to do with where the air was going!

It seems that the crappy print actually left some gaps in the top of the object, which happened to be the left side of the whistle. By putting water inside it was temporarily filling the holes. I could get the same effect by just giving a slight squeeze on the left side of the whistle with my thumb to block the airflow. Zing! Magic whistle. (Magic is just science you don’t understand, right?)

I then hatched a plan to trick the kids by having them try to blow into it, and then telling them they were doing it wrong, and then showing them how it’s done. I wonder if they’d see me squeezing the side or not.

Now I’m left thinking I need to design a new whistle with intentional holes. Anyway, that’s the sort of crazy stuff I do. You’re welcome!