For this week’s assignment, we worked on shape-transferring our own fingers using alginate and plaster.

Step 1: CREATING THE MOLD

The first part of the molding and casting assignment was to mix our molding material (i.e., mixing alginate with water). For the mold, we had to measure a 4:1 ratio of water-to-alginate by weight. Before that, I used a scale to measure the weight of my measuring cups, which was ~ 68 g.

Then, I pressed the “tare” button to offset the weight of the cup which allowed me accurately measure out 50 g of alginate.

Next, I used another measuring cup (using the same measuring and zeroing method) to measure out 200 g of water.

With the proper ratios measured out, I began mixing the two for a few minutes until I got the mixture to a pancake batter-like consistency. Then, I stuck my thumb into the mixture for ~ 10 minutes until the mold harden and I was able to take out my thumb with ease.

Step 2: Creating the plaster

With my mold now set, I was ready to make the plaster. For the plaster, we had to measure a 2:1 ratio of plaster to water by volume. I mixed ~40 ml of plaster with ~20 ml of water.

With the appropriate plaster ratios, I began mixing the two for ~2 minutes. Then, I poured the plaster into my mold. With the plaster poured into the mold, I partially submerged a screw into the plaster by poking a hole through a strip of tape and attaching the tape to the rim of the cup to secure the screw in place. This left the head of the screw exposed and would allow my mold to be used as a hook once dried! Then I setout both my mold and plaster to dry.

I repeated the same above steps to cast a second mold of my thumb!

Step 3: POST-PROCESSING

I let my mold and plaster dry overnight and came back the following morning to begin post-processing. I decided to color my thumbs using Rust-oleum’s Royal Blue spray paint.

After 3 light coats of paint spread ~10 minutes apart, I let my thumbs dry for the remainder of the day. The next morning, I came back and added two additional coats of Rust-oleum’s Crystal Clear Enamel. 

And with that, my thumbs were complete!

Cost estimate

• 1 lb of Alginate = ~$10
• 1 lb of Plaster = ~$10
• Labor ($7.50×3.5) = ~$23
• Material = ~$5
  • Plastic cups
  • popsicle sticks
  • Screw (probably find one laying around somewhere in the street)

• TOTAL = ~$50