In this project, we were tasked with creating a mold out of alginate and then using plaster of paris with the mold to cast a finger. To begin, I mixed alginate and water in an approximately 1:4 ratio by mass, or 1:1 by volume. My first mold was a bit of a disaster because I made too little alginate and didn’t have enough to fill the beaker, but I tried anyways by squeezing the beaker to increase the depth of which my finger was submerged. I then made a second mold, this time using a proper amount of alginate and successfully creating the cast.

Next, I started with the plaster. I mixed a very random amount of plaster and water (2:1?) until the mixture was somewhat thick. Then, I poured it into both molds and added a nail into the top because I didn’t find a screw within 15 seconds of searching.

I waited overnight for the plaster to set, took the fingers out, and these were the results. This was my first time casting and I think my plaster mixture was too thick, allowing an air bubble to become trapped in the good finger cast. The bad mold failed pretty spectacularly but it was all for science anyways.

I started a new cast using the same good mold and slightly runnier plaster mix and it should be perfect. I won’t be able to show a picture of the new finger yet because it’s still drying and this assignment is already quite late, but you’ll have to trust me when I say the new finger will be perfect. I’ll update this post probably tomorrow once I recover the casted finger and then spray paint the fingers pretty colors.

In conclusion, I think my casting experience went pretty smoothly. I learned a lot about proper mixing proportions am much more confident in my ability to cast objects in the future. And yes the joke is that the fingers were neither green nor thumbs.

Cost analysis (prices from Amazon):

Plaster of Paris: $0.30 – 2 oz at 15 cents per oz

Alginate powder: $2.50 – 2 oz at $1.25 per oz

Water: negligible

Labor: $30 – 1.5 hrs at $20 per hour

Total cost: $32.80