~ Whole new world of SQUISHY materials ~

Week 7: Molding and Casting

And how I had a multi-day operation on the Roland-SRM20 with the 1/100th inch endmill to create the SMOOTHEST SURFACE I have ever felt.

But first things first - a how-to from Jen:
Example of light blue oomoo cast in a blue wax mold to make an oomoo mold

Critical Components

  • design - double check positives and negatives. Soft material (silicones) cast in hard material and vice versa
  • design - make sure there's a hole/funnel shape for pouring in material
  • design - including a lip or overhang section to peel it off helps
  • design - for two part molds, having a "shell" to constrain motion is beter than tabs/pegs
  • maximize - could use both sides of the wax
  • material - check for hazards - some release toxic fumes
  • material - it expires, especially after being opened.
  • material - each part will stay viscous and hard to clean until mixed together. DO NOT let mix in container or where lid attaches or life will be sad.
  • cast - use gloves, cover surface, use disposable cups & mixers, clamp things to hold them tight, dispose by mixing both parts.
  • cast - make sure is WELL MIXED before
  • cast - may need vacuum to help remove bubbles. Otherwise tap it down on flat surface many times
'Sorta Clear' Silicone
Even though it looks bubbly, the surface of it is smooth, which is what matters.

Edible squanch

My goal: make edible iterations of the "squanch" design.
Unfortunately the design went through many iterations as I realized the limitations of the endmill and the desire to include a draft so the wider section of the endmill won't crash into the mold. (it's a cone-shape then a short vertical mill section) - ensuring the model is angled helps prevent this.
I then went to mill.
Files:
FreeCAD file | Svg file
end result
Milling
Rough Pass
Detail Pass

Super Detailed

Since this was the only chance I could use the Roland before another electronics week would kick in, I went for a super long test of the one-hundreths inch endmill.
Mods
carved piece
clamping to hold the wooden wall in place
sorta clear 37
Food-Safe mold!
Excess to experiment with

Tests

It works well with ice and (depending on how you make it) chocolate. Though I do have to warn anyone trying to microwave a Hershey's bar to beware, it WILL burn and char in the microwave.
I even had hallmates experiment with stuffing it with wasabi and freezing it (not pictured).
Chocolate squanch beside its kitchen-table-incarnation
Ice lighter