I have made finger casts of two of my fingers that have been spray painted blue! Here’s how I did it.
We thankfully started during the class period. Always nice to get some on-the-job instruction. Katy and I partnered up to share materials for the mixing bit. We mixed water to alginate in a 4:1 ratio (39g of alginate to 156g of water) and stirred the mix until a liquid, semi-gloopy texture (pictured on the left below) was achieved. For us, it took about 3 minutes.
After that, I quickly placed two of my fingers into alginate mixture, and held it in place for around 7 minutes, allowing for the mold to solidify. The top layer of the mold was still a bit wet when I pulled my fingers out, but I could feel that it had solidified for the most part.
(This is a picture of the mold after the whole process, including the casting, was completed, but I just wanted to show what it looked like)
Then, we mixed in the plaster with water at a 2:1 ratio, and poured the combination in to the mold. I quickly set up a screw in one finger’s mold, suspended by tape. I didn’t place a screw in the second finger, simply because I wanted one screwless finger.
Then, we left the cast to take shape. Two days later, when I pulled my cast out, I realized that I hadn’t placed my fingers deep enough into the alginate for a significant mold to have been created. Only the distal phalanges were present.
So I redid the whole process again. Initially, I made an water to alginate mix of 1:4, but then realized that the ratio had to be switched around, so I tried again. The mold came out with a deeper impression of my fingers, so I poured some plaster in and set it up the same way I had done it the first time. Here’s what the cast looked like when it came out of the mold the second time.
Perfect! I spray painted two of the best fingers royal blue and left it to dry overnight.
When I returned the next day, it looked like this. 
There were some patchy areas that were still the original color of the plaster, so I did a second layer of spray paint. After this dried, most of the fine details, including the nails and wrinkles, were still intact.
If I were to do this project again, I would probably add the screw to the other finger as well, because spray painting the screwless finger was a bit more difficult. Additionally, I should have had my fingers be a bit more curved, since these are supposed to serve as hooks after all. Also, I think I preferred the original color of the plaster to the blue spray paint, so I would perhaps use a clear coat instead.
Financial Model:
- Alginate: $3.48/1lb bag
- Plaster of Paris: $9.69/1lb bag
- Screw: $7.95 for 152 piece screw set
- Rustoleum Royal Blue Gloss Protective Enamel: $6.98/can
- 4 ours of Labor at $7.50/hr = $30
- cups, water, popsicle stick: freeish
- Total: $58.10 to buy a normal set of supplies to do this project at home.
