Molding and Casting (Week 9)
This was a very experimental assignment. I experimented with MDF and Moldable Wax and tried atleast 5 different designs and finally chose the one below. I made all of them in Inkscape, exported as bitmap at 500dpi for milling.
The experiment with MDF failed as the rubber cast got stuck in the board and refused to come out, even though I had used machine oil. The design here is slightly different from the final design. I realized my original design was turning out to be a pain to mill and decided to simplify.
My first experiment with mold-able wax wasn’t successful. The wax moved mid way and the milling bit left a hole right in the center (circled in black) which led to bad cast + bad final product.
The second time, I made sure that the wax is firm and used extra double sided tape to keep it in place. I used 1/8 flat nose bit for both the experiments and didn’t have to run the ‘finish’ command on Modella for final results.
The second try was pretty successful. I used PMC-121/30 for making the cast. The two compounds were mixed in equal proportions and poured into the mold-able wax. I decided to bake it at 175 for about 50 minutes to speed up the drying process.
Once the cast was ready, I made an MDF box to hold the drystone + water mixture.
Below is the image of the mold, cast and the final product -
On closer inspection, it turns out that the final product is not very smooth. Henry Skupniewicz, my colleague who manages the Fablab at CEPT, suggests using liquid soap to ensure settling of dry stone in the corners of the cast. Need to still experiment with this method, but here’s a closer look at my final cast product -
and the final mold -