Introduction
For the Molding and Casting homework assignment in ENGI 210, I used alginate-water to create an negative elastomer mold for my pointer and middle finger, which I then filled with a rockite-water mixture to create my two finger molds. Because I do not have prior experience with using these molds, I followed the beginner level instructions because I wanted to get the hang of how to use these molds. In this project I made 3 iterations of my pointer and middle finger molds and post processed them using some of the tools available in the OEDK.
The Process
Design
The design portion of this project was pretty simple with the negative mold of my two fingers being created by immersing them in the alginate-water mixture after it had become hard to mix with popsicle sticks. After waiting in this position for around 5 minutes, the mixture became hard enough for me to remove my fingers, leaving a negative mold of my fingers in the alginate mold. I then poured the rockite-water mixture into the mold to create the two finger molds.
2nd Iteration Alginate Mold of Pointer and Middle Finger
Fabrication
Before I set the alginate mold and poured the rockite into it, I mixed the alginate and water in a 4.5 to 1 ratio until it became difficult to mix. I also made a rockite water mix in a 1 to 3.5 ratio and once it was mixed thoroughly I poured it into the alginate mold. I waited about a day for it to set and then removed it from the alginate mold. This was a messy process and the alginate mold was ripped while removing it, so I would need to make another to make my second set of molded fingers. Another problem I occurred in the first attempt was that I overpowered the rockite so the two fingers had a connecting section that broke during removal. This section was hard to remove but I ended up breaking some off. However the breaks were not very clean and after some attempts with different files and sanders, the post processed fingers were nice enough so I scraped the first two.
First finger attempt after pulling mold from alginate
First attempt after some post processing
I then repeated all of the previous steps to make my second alginate mold and poured my second rockite mold into it. This time I made sure to remove the second mold a lot sooner at around 6 hours after pouring to make sure that the alginate mold was usable for a second pour. This worked out well and I was able to pour the third mold. Once this had been removed and both dried, I made sure to file some imperfections off of the fingers and then did some light filing to prepare the fingers for spray painting. I then spray painted the fingers with a light blue and left them to dry before then applying a clear coat.
Second attempt of finger molds
Fingers drying after spray paint coating
Final Product
The final fingers turned out somewhat nicely after finally drying. Fabrication and post processing took a few attempts to get right but I was able to figure it out enough to complete the project. Now I have 4 fingers ready to be submitted.
Final set of finger molds
Reflection
This project helped me understand the basics of positive and negative molding with alginate and rockite, along with how to post process clay like molds. If I were to repeat this project, I would have made a more refined pour the first attempt and I would have maybe sand blasted the fingers so that the spray painting would have applied more nicely. Overall though, it was good to learn this process and hopefully it will be useful for our final project.
Materials Used
Alginate (4.5:1 water-to-alginate ratio per mold)
127.5g (3 attempts)($10.20 at $0.08)
Rockite (35g per finger, 2 fingers per attempt)
210g (3 attempts)($6.30 at $0.03)
Screws
6 screws ($0.90 at $0.15)
Cups, Popsicle Sticks, Jig Materials
$2.00
Spray Paint + Clear Coat
$3.00
Labor (Mixing, Setup, Pouring, Cleanup)
20 min per attempt
$7.50 at $7.50/hour
Total
$29.90
