Welcome back to my blog! This week, our prototyping class delved into molding and casting, which was both interesting and exciting. I had never used molding and casting in any of my past projects, so this was a new experience for me. In our class, Dr. Wettegreen prepared mixtures of alginate and water for us to mold our fingers. He then provided a mixture of plaster and water to cast our fingers in the molds. Personally, I struggled to insert the screw into the surface of the cast; they kept sinking. Unfortunately, when I returned after two days to check my molds, they hadn’t worked as intended, so I had to redo the molding and casting without Dr. Wettegreen’s mixtures.

I began by mixing alginate with water in a 1:1 ratio, but soon realized I had added too much water and not enough alginate. To correct this, I started weighing the alginate to be more precise in my measurements, which resulted in a mixture with a similar viscosity to what Dr. Wettegreen had prepared in class. I then immersed my fingers in the alginate mixture for about 5 to 8 minutes, creating my mold. Next, I prepared the plaster mixture with a 2:1 ratio of plaster to water. The mixture seemed a bit watery, but I proceeded anyway. After letting the plaster dry for almost an hour, I returned to find the cast of my fingers perfectly formed and then proceeded to spray paint them with yellow and red.

Throughout this project, I learned the importance of casting and molding as a technique for producing specific shapes, underscoring its value in the prototyping process.

Material	Cost	Amount/Hours	Total Cost
Alginate	$19.99	15%	$2.99
Plaster	$8.99	25%	$2.24
Screws	$15.99	4	$0.15
Prototyping Engineer	$39	1	$39
Total			$44.38

We assumed that the tape and cotainers are provided by the OEDK.