For our final homework, we were assigned to to mold and cast some fingers. The molding and casting is one form of shape transfer, and will be the main focus of our final.
To start, we made some practice fingers using plaster of paris and alginate. The plaster of paris would be our positive, which is poured into a negative (the mold) created with alginate. We made a mixture of 2 parts alginate and 3 parts water. We would then stick our finger in and wait until the alginate solidified around our finger. The alginate doesn’t stick, so after solidifying, we safely took our finger out and poured a mixture made from 1 part plaster of paris sifted into 1 part of water. After a day, the plaster dried and we had some solid fingers. Unfortunately, the plaster of paris is very prone to breaking and dries rather slowly, so the finger I made didn’t make the cut. The class then started using some fast drying cement, and that’s where the project really started.
This time around, I decided to use 5 volume ounces of alginate to 8 ounces of water, since when I tried to recreate the mixture, it ended up much more watery than last time. I wanted to try a slightly larger ratio of alginate to water, and it surprisingly turned out alright.
I proceeded to stick my finger into the alginate and waited a good 15 minutes until the alginate was solidified. Once that was done I made a setup that will hold up a screw while the cement is drying in the finger. It consisted of some yarn tied around a No. 10 x 1-1/4″ wood screw that was held up by a popsicle stick that sat on top of the alginate container.
I proceeded to make my cement mixture. The instructions said 4 oz of water for everyone pound of cement powder. I decide that was kind of a hassle and I didn’t even know how much cement I needed, so I took about 1 ounce of cement and slowly added water while stirring to get a good consistency instead. It ended up with a nice cake batter consistency and I quickly poured it into the mold. Afterwards, I placed my screw setup above the mold so that the cement would dry around the screw and the screw would be able to hold up the finger when the cement was dry. After half an hour, I pulled out the cement finger and repeated the previous steps to pour more cement and a new screw into the already made mold.
Once both fingers have dried completely, I used some needlenose pliers to pry off the bigger pieces of cement away from the finger. Once I reached a point where I couldn’t confidently take off anymore using the same method, I started using a file to take off some more cement. To clean the fingers further and give them a smooth finish, I then followed up by sanding the fingers with some sandpaper.
I decided I wanted to make my fingers look a little bit more realistic in terms of color than spray paint could provide me. In retrospect, it only made the fingers look kind of waxy and fake due to the colors being a bit off and the paint filling up some of the wrinkles, but it seemed like a good idea at the time. I used some camel colored acrylic paint for the skin and a mix of red and egg colors for the nails.
The cost of the fingers were:
- Rockite cement ($15)
- Mixing containers ($5)
- Popsicle sticks ($2)
- Screws ($5)
- Yarn ($2)
- Tape ($2)
- Paints ($8)
- Brushes ($5)
- Alginate ($7)
- Water ($0.01)
- 3 hours of time ($21.75)
- File ($10)
- Sandpaper ($2)
- Needle nose pliers ($7)
In total, the project cost about $91.76. With that, the fingers were complete. On the to final!
