Memorial Garden III

After making paper and wood models ((check the journal ' Memorial Garden II' to see the details) last time, I decided to use concrete to make a model to test the function of the concrete. There are several ways to cast the concrete, such as using high-density foam or 3D printing to make a mould. Considering the cost and difficulty, I chose 3D printing mould. Although it seemed a shortcut, however, I still met a lot of challenges during the process of mould making and it was not as smooth as I expected. But thanks to the experience, I have learned something through making that I hardly learn only from sketching and planning.

Before making the mould, I designed a basic shape of the object, which will be cast by concrete later. I slightly changed my design based on the previous paper and wood models, which hollowed columns and connected them in the middle, it will look like a ribbon as a whole and will be more like the symbol of infinity from the top view. However, I did not waste too much time on design, because the point of the whole process was to test the mould-making and familiar with the properties of concrete. After finishing the design on Rhino, I sent my model to the Digital Fabrication workshop to print it, then I watched the tutorial on the concrete casting of miniature objects on YouTube and decided what I should purchase for the casting. I bought rubber bands to tight the moulds up, and petroleum jelly to make the object easier to separate from the mould.

Preparation of the concrete casting

However, I met a problem when I mixed the cement and water, which I poured too much water. When I poured the mixture into the mould, it leaked from the gaps of the mould, and I could see the water level of the mixture in the mould becoming lower and lower. And of course, it was leaked also because the precision of the mould was not as high as I assumed, and moulds were not connected tightly. However, I believe taping the mould up would fix the problem. The second problem is I was been told that I was not allowed to use the cement on the 4th floor, which interrupted my casting process, therefore I did not finish the bottom part.

The process of casting

I assume that the result will not be ideal due to the problems I have met. As I predicted, because of the bad quality of the mould, the object has prominent parting lines. Fortunately, the object separated from the mould smoothly and remained complete.

Models and the mould

Concrete model

Another problem is the bubbles. I realized that a chemical reaction would take place when the cement and water mixed, which created the amount of bubbles. Although I followed the tutorial and shook the mould after pouring the mixture, they still appeared. It means I was shaking not enough and maybe I should have the tools like a hammer to hammer the desk to vibrate the mould next time, it would be more effective. But interestingly, these bubbles gave the surface of the concrete a little bit of texture.

The detail of the concrete model

I gradually familiar with some qualities of the concrete through this experience and I believe it would be useful when I attempt to do another similar test next time. I plan to explore the combination of concrete and other materials to make the material more appropriate for the theme. Another key for the next test is to adjust the design and try to create a more textured surface to embody the keywords 'timeless' and 'light'.