Respiratory movement: Flexible part

This article is part of: The Green Observatory.

Table of content

Making the mold

  • freecad design
  • laser cut test
  • laser cut test, clean the lens
  • assembling, holes too small, had to re-do them with the hand drill

lasercut acrylic transparent 5mm: 95% power, 0.45 time, 20000HZ

Preparing the casting

  • Spray release agent, mask and gloves, wait for 10 min
  • calcuate the volumes I need to cast (Pi * radius * radius * height)
  • 50% of A, 50% of B, mix super well for 5 min
  • put a timer of ~ 20 mins (according to the specs of the silicon I'm using)
  • Pour the solutions slowly, to avoid the creation of bubbles, in the mold
  • Wait for 5 hours

Other side

  • Unscrew the structure and flip the mold
  • Clean everything
  • Place the disk in the center, on the top of the first layer of silicon
  • tape the holes (with transparent tape)
  • Calculate the new volume to cast, and prepare the silicon mix
  • Cast and try to reach around 1 or 2 mm of thickness


Mistakes encountered

  • The two holes in the design were too small compared to the pipes, I had to enlarge them with an hand-drill
  • I calculate the volume without substracting the inner pieces, I ended with a waste of silicon (which is expensive)
  • I've used white tape, which is way more too visible and thus un-aesthetic
  • The first try of casting the second layer was too thin, the inflation worked but I tore the membrane

Created 04/06/2020

Updated 04/06/2020