Juliana Cherston

How To Make Almost Anything

Molding and Casting

This week, we used the Shopbot to mill out wax and used the wax to create a silicone mold. We then cast the object in different materials, and spray painted as a final touch. I chose to make a cast of the Talking Doorknob from Alice in Wonderland to attach to my doorknob... my room is filled with small airplanes, model hot air balloons, physics-inspired canvases, surrealist quotes, and other fun things, so a bit of Alice in Wonderland fits right in.

  • Project:Molding and Casting
  • Date: October, 2014
  • Skills: Making molds out of milled wax, casting, spray painting
"Sorry, you're much too big, simply impassable." "You mean impossible?" "No, impassable! Nothing's impossible"
Above is a peak at the progression from design to finished product. I played around with my doorknob and determined that it most definitely could not be taken apart without cutting straight through the piece. Thus, I knew I'd have to mold two parts that could fit around the knob. I started off my making my model in SolidWorks. I imported an image of the character and traced it, then extruded in varying degrees. I hoped to add more texture than Solidworks allowed...props to Amanda G. for helping me find Mudbox, a truly remarkable program that lets you push and pull meshes around like a block of clay! Although I had a lot of fun playing around, I worried that the design might come out looking messy, and so ultimately opted to print the flat version and save some more subtle work with Mudbox for another time. [Pro tip: if you'd like to use Mudbox with a SolidWorks file- you'll need to use Meshlab to convert from STL to OBJ formats).
A big thank you to Chikara for helping me through some problems while milling. As you can see from the photos above, I milled the two parts at the same time in case I needed to make small adjustments to the wax by hand to fit the doorknob properly (this turned out not to be necessary). My side borders were far too fine, and as a result were completely cut off. I also forgot to add some depth to the cut. I ended up recutting right below my original cut, but at the bottom you might notice that somewhere in this process I accidentally cut a bit more deeply. I tried to repair the piece with hot glue, which turned out not to be the best solution since it left some unwanted texture to the doorknob's chin. Fortunately It's not extremely noticeable! I might have been better off repairing with putty, but couldn't find any around.
Since my walls were cut off, I had to use some plastic scraps as makeshift walls wall constructing my silicone mold. They were easy enough to attach to the wax mold. I made my Oomo (fun!) and then cast in Smoothcast plastic. The pieces turned out great! I bought some gold spray paint from Artist and Craftsman in Central Square and spray painted the pieces. Then I borrowed some paint from LLK lab at the Media Lab to paint the eyes. I was so eager to assemble that I didn't let the paint dry enough! Be patient with spray paint :)
Excited about the final result!