This blog is dedicated to the sublime instruments called nose flutes and which produce the most divine sound ever. We have chosen to discard all the native models from S. Pacific and Asia, for they need fingering to be played. We'll concentrate on "buccal cavity driven" nose flutes : the well patented and trademarked metal or plastic ones, plus, by a condemnable indulgence, some wooden craft or home-made productions.

Jan 17, 2013

Moulding and Casting - Part 5: Casting acrylic

It's a long time I've been wanting to experiment with casting nose flutes. As a model, I chose a Bocarina, because I love those babies, because they are easy to disassemble and because they are produced by ABS injection... in a mould.

My goal is not to forge a Bocarina, and certainly not to make a market with that (anyway, moulding and casting is much more expensive that buying the original nose flute!). Chris Schuermans had authorized me to experiment with a mould. Indeed, my goal is purely recreational.

[Sequel of the posts Part 1: Hard silicone, Part2: Casting urethane, Part 3: Low temp alloys and Part 4: Soft silicone]


Moulding and Casting - Part 5: Casting acrylic

I wanted to cast also acrylic resin, in order to (try to) get a translucent Bocarina, because polyurethane is opaque. My hard silicone mould was beginning to be a bit worn, and I used my new soft mould.

The problem with such resin is that, contrarywise to the polyurethane which hardens in minutes, acrylic takes at least 24 hours to harden. In consequence, the smallest leak in the junction of the mould leads to a disaster: in 24 hours, all the content is able to flow out.

I was finally able to seal my mould with tape, and had only one refill to do after 12 hours. It took me 7 castings (one week:) to get one proper flute:

The other problem (that I have not totally been able to get rid of) is the formation of bubbles. When you cast the resin, you can lean the mould to avoid bubbles in some angles. But the acrylic resin produces bubbles during its hardening process. Micro-bubbles, but during the 24 hours, they have the time to gather in bigger ones.

For those, I had to make "patches" afterwards, that is, to re-cast resin in the little holes.

I made 2 of them, one transparent, and one that I sanded to get a "translucent glass pebble on the seashore" aspect.

I also tried with a stock colored acrylic resin, and one in which I mixed a drop of red colorant (dedicated to polyurethane)

The results are funny, but not impressive on the sound side. All are very sharp (probably due to the shrinkage), with a reather "plastic" sound. Anyway, such slow hardening resin is a real pain in the neck to work with in such silicone moulds. Won't do it again.

Some were asking how would it look with a transparent nose flute, super-cool or like wearing a medical mask on the face... Maybe a good flute to teach nose flute playing? Well, you are the judge:


On the same topic :

- Moulding and Casting - Part 1: hard silicone
- Moulding and Casting - Part 2: casting urethane
- Moulding and Casting - Part 3: low temp alloys
- Moulding and Casting - Part 4: soft silicone
- Moulding and Casting - Part 5: casting Acrylic



  1. I just love your work on the moulds and with all these different materials! These must have taken ages... I particularly like the transparent ones as objects.

    Even if they are not that great as instruments, they still make (yet another...) wonderful addition to your amazing collection! Can you make an estimate of just how many there are in your collection? Could you even try and catch them all in one picture?

  2. They look great. So sad that the material is very problematic.

    I also think that they are a fine addition to your collection, so all your hard work is not lost.

    Thank you for showing them.

    You look fine and a little funny in the picture, The thick material on the side of the window make it look like you have vampire fangs.

  3. Thank you guys!

    Yep, they are just tests... and acrylic is not a good stuff, particularly for the sound. No problem :)

  4. To Maikel: how to estimate....?

    I mean: how many different Bocarinas? One? One hundred?

    How many metal humanatones: one? or 3 because I have 3 different models (different rivets and so...)

    How many swirled plastic Humanatones? should I count one or twelve? Are they the same or not ? I should count 12, because I would count 2 of the bigger model of Akio Takamura, which are painted differently? Or should I count only one?

    You see the problem...