noseflute.org: Moulding and Casting - Part 1: hard silicone

Dec 19, 2012

Moulding and Casting - Part 1: hard silicone

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.

Moulding and Casting - Part 1: Hard silicone

Well, the first thing to do for casting an object is to create a mould. I have a correct stock of silicones and resins that are at their conservation limit date, so it was the right moment.

First, I disassembled a Bocarina^™, by tapping the insert out with a small mallet.

Then I removed the salient sliders of the insert, and clogged the concave parts of the body, with Fimo clay.

I prepared the body for the casting of a 2 parts mould:

I cut some tin sheet to build a box with a bottom with punched holes...

... and prepare a base for the Bocarina^™ with soft clay.

Finally, silicone! I used a RTV silicone, added some silicone oil for fluidity, and cast it over the nose flute.

After some hours, I was able to unmould, thanks to the holes of the bottom of the box, and got a perfect imprint.

Then, cutting the air ducts, necessary to avoid big bubbles, and applying some talcum powder to absorb possible greasy residues.

Finally, I coated the first part with vaseline, and placed the Bocarina^™ back, after having removed the adhesive tape.

I casted the second part, and placed a little sign to mark a side.

So, I obtained a (almost) perfect mould (no bubbles). I finally cut the salient "negative" parts of the air ducts, and applied talcum on both parts of the mould. Ready!