Tubes — some experiments
February 16, 2020 at 10:41 pm #11188
Like so many before me, I tried and failed to find a source for flexible tubing as is commonly used for melodicas, or alternatives, etc. Even places like this had nothing useful when I inquired.
But I found that if I used half-inch (outer diameter) rubber tubing from the hardware store (5/16 I.D., .1″ walls), I could wrap it in techflex (I used 1/4″ techflex, and needed about 46″ of it to cover about 2 feet of rubber tubing.) I taped the ends with 3M black electrical tape (generic vinyl electrical tape is terrible) which is necessary because the techflex will rapidly unravel wherever it is cut.
The idea was to have the smooth inner walls and flexibility of the rubber hose, but use the tech flex to constrain the expansion (the 1/4″ techflex is basically maxed out when expanded over the 1/2″ hose) since I expected the rubber hose to blow up like a balloon when air pressure was applied.
I was super proud of the result… in fact, the techflex/tube combo has even less inflationary stretch than the original corrugated tubing, and it looks pretty good, all things considered. But then I tested a piece of the rubber tubing and realized that just bare it has less stretch than the original corrugated tube. So, except for the aesthetics, there doesn’t seem to be much need for the techflex. It does make the tubing slide a bit easier, so it won’t hang up on clothing as much, etc, but now I’m reaching. 🙂
And there is a potential drawback: at first it seemed like the rubber hose was collecting way more condensation than the corrugated tube, necessitating a blow-out every other tune I played. I don’t know if this is because the rubber hose takes longer to warm up to breath temperature, or because the corrugations in the original tubing tend to slow the condensation from running down the inside of the tube. I’m not sure yet if it’s a bug or a feature… maybe it keeps more of it out of the melodica itself.
It also remains to be seen how long the electrical tape lasts…
Here is a picture. From left to right: the 1/2″ rubber hose, the 1/2″ rubber hose wrapped in techflex with a 3d-printed replacement elbow fitting for a Hohner Piano 36, the original tubing with a 3d-printed elbow, the original (repaired) elbow with a 3d-printed elbow, and a suzuki tube and fitting:
Here’s a close up of the techflex tube:
Here’s the link for the .stl file for the elbow: http://caseyconnor.org/pub/image/melodicas/hohner_mpiano_36_elbow_v2.stlFebruary 16, 2020 at 10:44 pm #11189
Um… don’t know why the IMG tags didn’t work… here they are in link form:February 16, 2020 at 10:46 pm #11190
Ah, maybe the https… let’s try http:February 16, 2020 at 10:47 pm #11191
Argh, nope. Here are plain links with no https:February 18, 2020 at 10:44 pm #11195KevinParticipant
Very interesting Clep. I’ve had pretty good luck with the surgical tubing. The drawbacks I’ve found is if it gets bent at an extreme angle it will sometimes kink up and block airflow also any accidental pressure on it will block airflow.February 18, 2020 at 11:26 pm #11196
Yeah this stuff doesn’t seem to kink too easily… the walls are pretty thick. And I think one bonus of the techflex is that it helps a little with that as well.
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