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10. Molding and Casting

Positive Negative Postive Negative Positive Negative

Notes & Things

  • OOMOO Neil’s product recommendation
  • Silver Casting
  • Design the mold around the tool limitations

Process

  • Started by working in Illustrator and Fusion 360 to extrude an SVG shape and bevel edges. Lots of Fusion issues with the mesh–remedy may be to work exclusively in Fusion: Designing CAD model of Twin Peaks Owl Symbol in Fusion360

  • Experimented using MODS for CAM: MODS file workflow

  • Switched to VCarve CAM and simplified the file (beveling the facets on the mesh yielded many issues so I simplified the design for proof of concept):

VCARVE pro CAM model

  • Finding the right bits in the Chaos Drawer (1/4” upcut for roughing and 1/8” ballnose for finishing pass): Chaos drawer of bits for ShopBot CNC

  • We cut a pocket in plywood secured to the ShopBot Bed that was the dimension of the Wax Block; then we malleted the Wax Block into place. Here we are performing the roughing cut: Roughing cut on the shopbot into blue wax block

  • Several issues–there was some chatter or strangeness to the file, and the milling looked a little chewed up. But… time moves forward, and perfect is the enemy of done. So, the learning continued, and I attempted to use expired OOMOO because we were unable to get new Silicon for the mold (#siliconshortage). Here is my setup (note the gloves and eye protection I am wearing… trust me on that last part 🥽):

OOMOO casting setup

  • As mentioned, the expired OOMOO was very hard to mix (the pink part was the consistency of taffy), but… I sort of made it work:

OOMOO cast in the Wax block

  • Woot! A very bubbly mold that sort of works! This excercise was to quickly go through the workflow process, as I definitely want to cast more things in the future! But MVP for now: Silicon mold with Twin Peaks symbol

  • Cast going into the deep freeze (Ice Test for proof of concept, not consumption): Casting test with water

  • We’re call this success! A 20 Second Twin Peaks themed Ice Cube!

twin peaks symbol cast in ice

Cast Ice in Glass

Melting Ice Cube in Glass

For Next Time

  • Design STL in one program–not multiple
  • Start with designing the positive (desired cast outcome); then build an enclosed area block around the positive and send to mill (roughing/finishing pay attention to step over for smoother outcomes); then create the negative mold with Silicon or similar in the wax block; then cast material into mold
  • Non-expired OOMOO and high temp Silicon for metal
  • Stock up on flat bottom plasic cups and popsicle sticks
  • Vacuum chamber to pull air bubbles out of the silicon before it is poured
  • Release lubricant (optional–I actually had no issues at all with things sticking)
  • For food casting be sure ALL parts of the process are done with food-grade materials

Design Files

Last update: March 27, 2022