Week 7: Molding & Casting

Assignment: Create a mold using 3D milling and cast it.

Making the design

I used Fusion 360 to create a design. I wanted to stick with my theme of modular pieces for my apartment so I thought I’d make a candle holder that was flippable and stackable to make different aesthetics. I played around with a few shapes in Fusion and ultimately decided to make a geometric shape. I then tried a few assemblies to see how it would looked when stacked and flipped around.

Molding

Making the mold ended up being more annoying than I anticipated. I had two failed attempts before I finally got it working. The first time around, the ShopBot had an electric issue and decided to turn off half way through my finishing toolpath. The second time around, the mill went a bit too far down and ended up ruining the wax and my design on its last path (picture below). I adjusted the depths finally, the third time around it worked!

week7fail

The actual process of using Oomoo was pretty easy and worked out great! I just had to make a cardboard wall around my mold to avoid spillover. In retrospect, I probably should have made it higher since it was hard to put the mold into the vaccuum after pouring the Oomoo since I was scared it would spill over.

Casting

I really wanted a grey aesthetic so I decided to get some craft cement (yay Amazon!). I mixed the cement and added it to the mold. I had contemplated making a two part mold and making the hole for the candle as part of the mold design. However, I didn’t like the line you get at the joint and thought I’d try just setting a candle in after. This seemed to work pretty well. I put a candle at the top and bottom to make the candle holders invertible. The only problem I encountered was that the cement on the top candle seemed to bubble a little and created a bit of an uneven edge. I figured I would just sand it later to get a cleaner finish which worked out quite well. I made two candles so I could try out stacking them!

Finished product

I’m really happy with how it turned out! A few things I’d want to improve next time would be making the finish of the top part better. I could probably make a flat rubber piece and put this along the top or design a two part mold to get this to come out cleaner. I ended up painting alternating triangles with white to highlight the geometric shape. I think I’d also want to use a piece slightly larger than a tealight for the bottom since those tealights were hard to break out of the cement. Regardless, it was a perfect creation for Diwali!