This project was a great introduction to molding and casting. The best part of it is that it didn’t take me too long to do it in comparison to previous projects of the semester
- Molding & Casting
I was hoping to use the finger made during class as one of the fingers for the assignment but the screw inserted in the finger was not straight, leading to make it visible though the cast.
The first thing was to create the mold where I was going to insert my finger. I began by using a 1:4 weight ratio of alginate casting material to water. This means that the casting material weighed 50gr and I used 200gr of water. Then, Tak (a visiting professor that makes really impressive designs) suggested pouring the powder into the water (room temperature water) so this way it’s easier to mix both materials and you avoid having powder at the bottom of the cup. Then, I put my middle finger into the mixture and waited only 5 mins to take it out as I could already feel that the cast mixture hardened.
The next step was to create the mixture for the cast. For this I also followed Tak’s recommendations as he is an expert by measuring 1 finger of room temperature water of the big cups and adding plaster to it until we could see the plaster as a little island popping out of the water. I don’t know the exact ratio but I would approximate it to one full plastic cup. Then I mixed with my hands to get rid of the small clusters and bubbles that you cannot eliminate with the stirring stick. After pouring the mixture to the top of my finger I placed a screw with a string around it into the hardening plaster. I left it dry for 2 hours, Figure 1.
Figure 1: Plaster drying
After 2 hours I took the mold out of the cup and with a cutter box I cut the mold to be able to take my finger out of the mold. I wanted to do it in a zigzag pattern to be able to use the same cup but didn’t know the exact orientation of my finger and ended up cutting the entire mold. I repeated this whole process once again to obtain my second finger. They don’t look exactly the same but close enough, Figure 2.
Figure 2: Fingers before being painted
The last step was to postprocess the finger by using a metallic spray paint and remove the strings from the hook, Figure 3.
Figure 3: Final fingers
2. Cost analysis
- Alginate ~= $2
- Plaster ~= $1
- Spray paint ~= $5
- Labor ($20/hour) = $25
Scale, mixing cup and stick, 2 screws not included as they were provided by the OEDK.
- Total cost: $33
