This week we did casting and molding! I have never done this before, so this was an exciting experience. Of course, I had trouble with this assignment, which I will get into.

In class, Tiffany and I worked together to create our alginate and plaster mixture. For the alginate, we used a 4:1 ratio of water to alginate (200 g:50 g). We stuck our fingers into the mold and held them in place for about 1o minutes until the alginate was completely set. Both of us used two fingers on the same hand to expedite the process. I decided to hook my fingers so that I could actually use them to hold things once this assignment was complete. Once that was set, we mixed a 2:1 ratio of plaster to water (20 g:10 g), then poured it into the molds. Tiffany tapped the bottom to get bubbles out (I did not) and we set them outside to dry.

A day later, I decided to check on my casts. Because my fingers were curled, it was hard to wiggle it out. I ended up taking the entire mold out of the cup and ripped it open sideways to remove the finger cast. Weirdly enough, there was a large bubble at the tip of my fingers. Perhaps I didn’t fill enough, or it may have been because I didn’t tap the cup when filling:

Even though it had been 24 hours days since I cast the finger molds, I couldn’t help but feel that the plaster hadn’t set properly because it was slightly wet (though it seemed more because of the alginate moisture) and crumbled easily. It may have been due to the high humidity outside while it was drying.

One of them also fell from my hands, so I decided to redo the assignment.

This time, Anjitha (who was also doing her assignment) and I got to work making the mixtures. We actually ended up getting the ratios flipped, and used a 4:1 ratio of alginate to water, which would not mix properly at all. With some intervention from Dr. Wettergreen, we were able to fix the solution and redo the rest of the steps with ease. This time, I put my fingers straight in so they could be removed easily. I set it outside to dry, though at some point was taken in to dry on the class table.

This time I waited two days before checking my molds. Drying it inside must have helped as well, since it removed easily and looked pretty set as well! I had poured the extra plaster on top of the fingers and added the nails. Upon removing, one of the fingers stayed on it while the other came off. Honestly, I was scared to remove the first one in case it ended up breaking (I should have made several!) so I screwed the other one back in. There were some small air bubbles that got stuck on the fingers as well, but overall the casting was pretty uniform.

For post processing, I decided to go simple and just spray with some sealant since I liked the white plaster look:

 

This was a really fun module, and I am excited to try casting/molding again for the final!

Cost breakdown:

• Alginate powder: $8.99
• Plaster of Paris: $9.69
• Labor: $7:50 x 1 hour = $7.50

Total: $26.18