With spring break on the horizon, the team continues our work on the car. Some of the team members noticed that our canopy was not the most aerodynamic, so, over break, we decided to reconstruct it entirely. Lovie Sia (9) and I (9) have been working diligently on this new project. We began by creating a foam mold so that we could heat up acrylic or another transparent flexible material and shape it into the form of a canopy using a press. Our previous 2019 car used a lot of foam in its design, so all of the tools required for this project had already been made by previous members of the team, saving a large amount of time. 

First-generation cut of the canopy

For our first-generation cut, we used a hot wire attached to a block of wood as our foam cutting tool and had success. Neither of us had ever cut foam with a hot wire and were shocked that the foam turned out to be a clean-cut. However, this smooth cut did not come without a lot of preparation beforehand. Since we were new to the concept, it took us a long time to understand how to smoothly cut the foam. We spent a week understanding how each of the tools worked and how we could create a proper jig in order to make the smooth cut. Making the jig itself also required a few days as we needed to ensure that when the foam was cut, it was the right dimensions. Our first jigs resulted in failures as our cut was always a few centimeters off. However, we learned that we could sand the foam down to the correct size and eventually ended up making a jig that was slightly larger than necessary. After various complications such as the tools falling apart, we were successfully able to create a foam model for us to test. 

Since the first cut, it has been a few weeks and our skills have improved substantially. Through trial and error, we also found the most effective settings for our tools and the easiest jigs to use.

Refined version of the canopy after many small changes

We are not professionals; as a result, we make mistakes. Our recent full-scale test took a turn for the worse after our setup suddenly moved on the table, causing the hot wire to slice off needed portions of the foam. We were only able to see the mistake after we were finished as we couldn’t exactly look underneath the solid block of foam. Although the foam was ruined, we discovered that it still might be salvageable. Our mentor gave us the idea that we should try using drywall plaster to fill in gaps and holes as it can be easily sanded and is incredibly easy to work with. We took a shot at the idea and found success! The plaster was able to stick to the foam very easily which further improves the smoothness of the mold. However, sanding proved to be difficult as the drywall dust filled up our sandpaper, rendering it useless until it was washed. We hope that we can further improve our foam cutting techniques and end up with a working mold in the future.