Introduction

For this project, I learned how to create a mold and cast my fingers! This is a very straight-forward, simply process; however, I had to do the process three times before I got a good pair of digits. In this blog I’ll delineate my presumptions, where I went wrong, and how I triumphed over these setbacks.

Step 1: Molding 

To make the mold, I used the provided ratio of Alginate and water from the sheet on the table, NOT the one in the Google Doc. I used 6.75 ounces of Alginate for every 1.5 ounces of water, which makes a 4.5:1 ratio. As I was combining the two substances, I made sure to stir them together for easier homogeneity. Once all the clumps were removed–as well as they could be–I stuck my fingers in the mixture for five minutes. I carefully removed my fingers, which were firmly adhered to the solution.

Step 2: Casting

To make the casting solution, I used a 3.5:1 ratio of Rockite to water by weight, so 35 grams of Rockite and 10 grams of water per finger. I initially didn’t notice that the instructions switched units from ounces to grams, so I was about to fill multiple cups of Rockite to get 35 ounces (do not do this lol). I called Madison and she thankfully helped me realize my silly mistake. I then put the screws into the 3D printed guides, aligned them to the concentric to the visible end of the finger, and left them overnight to set. I did one finger at a time, and noticed that one of them had already cracked when I adjusted the metal nail, so I made another batch just incase. I thought this would save me the headache of having to come back to the OEDK to redo the fingers, but I was wrong.

I came back the next day and found that only one of the four fingers I made were viable. One of them had cracked when I was originally adjusting the screw, and another two had the screw head sticking out of the side of the finger. Although the fingers would have still worked, they did not look as nice/well-done, so I went through the whole process again and made another set. Thankfully, one of the pairs of fingers pulled out nicely and preserved the Alginate mold, which I reused for the third batch of fingers.

 

Reusing the mold for the third pair of fingers^^^ ///  The screw comes out of the side of all three ^^

I came back the next day to find that the screws were only visible out of one end of the fingers. To make sure I got it right this time, I was more cognizant of aligning the screws with what would be the bone of the finger rather than sticking them straight down into the solution. With screws corrected, I was ready for step 3.

Step 3: Post Processing

I used some failed fingers to test different spray paints and settled on silver because it highlights the details of the fingers well. I made sure to cover the screws with painters tape, and spray painted them outside. I then waited a few hours and applied a gloss to them as well. To make sure they dried well, I plunged the screws into a piece of cardboard (I saw this technique on another student’s blog and thought it was smart to do).

My final thoughts…

Overall, I was glad to learn how to mold. Since it was a completely new process, it seemed a bit daunting, especially since the materials are (that kinda freaks me out, I’m used to working with rigid materials that can’t spill). I can definitely see the application of molding and casting, and am glad I faced the seemingly unnecessary setbacks so I know what to avoid in the future.

<–Clean work space

Cost Analysis

Alginate (13.5oz) : $12 per 24oz, $6.75

Rockite (210g): $23 per 4536g, $1.06

Spray Paint: $0.50

Labor: $15 per hour for 3hrs

Total: $53.31