Over the past couple weeks, I learned how to utilize alginate and plaster to create replica molds of my fingers and cast them to create wall hooks. I had never done anything with molding and casting and this was a great introduction to the process for me. Overall, I had a lot of fun with this project and I really enjoyed learning how to create molds and cast them.

 

My Process

For my first finger mold and cast, I started this project along with everyone else during class. Following the instructions given by Dr. Wettergreen and the TA’s, I utilized a 4:1 alginate-water ratio and mixed it together for around 5 minutes. After my mixture was thoroughly mixed together, I stuck my finger into the alginate and let the material harden around my finger to create the mold.

Figure 1. Alginate Mixture

After carefully pulling out my finger, I mixed my plaster in a roughly 2:1 plaster-water ratio. After my plaster looked around the consistency of pancake batter and did not have lumps, I was ready to pour it into my finger mold. After my mold was filled to the top, I tapped the mold to release any air bubbles and inserted the screw that was held by a popsicle stick at the very top of the mold.

Figure 2. Casted Finger Drying Inside Alginate

After letting the cast dry (for maybe a couple days too long), I wiggled my finger out of the alginate and inspected it. I did not realize that the molding and casting would be able to carry over so much detail like the wrinkles etc. on my finger. Although there were some air bubbles and bumps on the finger, it looked really good and I was overall really happy with how it came out.

For my second finger, I was initially going to remake a finger mold out of alginate and cast it again. However, since I kind of forgot about the project until the Saturday night before it was due, there was no more alginate left. As such, I decided to reuse the alginate mold from my first casting. Although it was clear that the mold had shrunk a little bit as the homework document stated, it still fit my finger well so I was comfortable reusing it. After mixing more plaster together (with some more trouble this time), I poured the cast in to the alginate and held my screw over the plaster until it hardened enough to hold on by itself.

Figure 3. Reused Original Alginate Mold

After letting my second finger dry, I pulled it out and I was ready to post-process both fingers. First, I just took some box cutters and cut off any excess plaster on the very bottom of my fingers. Then, utilizing 200-grit sandpaper, I sanded down the edges of the bottom to make them smooth and any bumps on the fingers.

Figure 4. Post-Processed Finger Hooks

Finally, I was ready to spray paint and clear coat my fingers. I was a little scared that the spray paint would mess up the detailing on the fingers and I actually liked the color of the plaster so I decided to just clear coat my fingers. For my first finger, I decided to utilize a matte clear coat and for my second finger, I decided to use a gloss clear coat. Finally, I was done with my two molded-and-casted finger hooks.

Figure 5. Clear-Coated Final Finger Hooks

 

Areas of Improvement

Overall, I am happy with how my fingers came out, especially my first finger as it was able to capture a lot of details on my finger. However, I do think that there are some areas for improvement. One big area of improvement would have been creating a second alginate mold for my finger. As such, I would have been able to create two fingers that were roughly the same size. However, since there was no more alginate left, I had to reutilize my first alginate mold. Since that mold had been left out to dry for a couple of days, a lot of the moisture in it and dried and, as such, the second finger mold that I created was noticeably smaller than the first finger mold that I had created.

Additionally, there are some other improvements that I could have made, mainly on my second finger. My second finger definitely did not have as much detail as my first finger, which I assume is due to the fact that my plaster mixture whenever I did it myself was significantly worse than the one I made in class. Additionally, I am not sure how, but it seems like there was some alginate that stuck on to my second finger casting. Furthermore, my second finger cast seemed to have chipped a little inside the mold.

Figures 6 & 7: Alginate Left on Finger and Chipped Finger

Finally, I think I did not eliminate the air bubbles in my plaster correctly as there were some holes that formed on my fingers.

Figures 8 & 9: Holes in Fingers due to Air Bubbles

 

Cost Analysis

For this cost analysis, I will look into the cost of: alginate, plaster, silicone cups, screws, clear coats, and the cost of my personal time.

For the alginate, I found a 1 lb. bag costs around $13.39 and since I only made one mold, I will approximate the cost as around $3. For the plaster of paris, I found a box of 64 oz. costs $7, which I will approximate to around $2 for how much plaster I used. I found a set of 3 different silicone cups, similar to what I used, for $7 from Target. A 1 lb. box of screws costs around $8 from Home Depot and since I utilized two, I will approximate that as around $1. The two different clear coats cost around $9 each. Finally, I spent around 4 hours on this project and since my pay is $10/hour, this project cost me around $40.

Overall, this project cost me around $71 but, if we account for the alginate and plaster being common materials given, it costs around $66.