Silicone Molding with 3D Prints

I tried something a little different recently after seeing this video from Prusa Printers: https://blog.prusaprinters.org/the-beginners-guide-to-mold-making-and-casting_31561/

I had seen examples of people creating really cool resin/soap/candle casts from silicone molds created from a 3D printed object and thought it looked really fun. It could be used to make gifts or little trinkets. Also, why not try something new? I’ve been playing a lot of Animal Crossing and Zelda:BOTW recently and thought I could make something using the star fragment design.

I spent an afternoon modeling the fragment in Rhino (which took more time and math than I expected- shout out to this woodworker physicist’s blog for helping me with some of the math to get the angles right). The star fragment is a small-stellated dodecahedron, simply meaning a 12 point star. So there was a lot of Rotate3D, Orient3point, and mirroring going on while modeling:

You can see from the bottom left two models in the image above that I ended up splitting the star in half so I wouldn’t have to deal with support material while printing. Plus, since this isn’t a finished product anyways, the seam wouldn’t matter on the print. Printed in color changing PLA (I had to use it up) on my Prusa:

After sanding and gluing the two pieces together, I set up a makeshift workstation on my dining room table to create the silicone mold. I purchased silicone, a silicone release spray, clay, and some beeswax I was going to make the cast with (I originally thought I bought soap pellets, but beeswax worked as a trial attempt since it hardens relatively quickly):

One thing I did differently from this photo and use a cardboard box lined with plastic rather than a plastic Tupperware container. It ended up working better than I expected (minus a few leaks). Like they showed in the video from Prusa, I surrounded half of my 3D print with clay, then filled the other half with the silicone mixture:

The silicone hardened quite well and I was able to pour the other side without issue (I forgot to take any photos of that). One issue I knew I would face was removing the print -and future casts- due to how much overhang there was to the model. I was hoping the silicone would prove flexible enough. It did up working, albeit with some extra force. The silicone cast was near perfect and even captured the 3D prints small imperfections:

I melted and poured the beeswax and *drumroll* the final product turned out great. I won’t lie, the first iteration wasn’t great, but I learned to let it sit for a few more hours and hold the silicone mold together tightly with the rubber bands. Here is the final pour:

And next to the original print (which is still covered in some leftover clay):

You can see some imperfections on the wax version (I think one of the silicone mold sides shifted a bit), but I am quite pleased with the result. I plan to do another cast, this time with actual soap, and will be sure to post the results. Thanks for reading!