The next skill on our list – molding and casting. For this assignment, we used alginate, plaster, and screws to make two wall hooks shaped like our fingers. We practiced the process once in class and it went pretty well, except that we didn’t pull our plaster out of the mold soon enough. Many of us were traveling during the Thursday session after we made our casts, so the fingers were left in the alginate for five or six days and were still damp when we pulled them out. This was an important lesson to keep in mind when we worked on the next iteration.

I worked with Pablo to make the next version of the finger hooks. We had a little trouble mixing the correct ratios of powder to water, and we needed to get the timing of our mixing just right, so we had to mix each material twice. The first time we mixed the alginate, we let it sit too long while we were preparing to pour it into the cups, so it was already starting to solidify and we didn’t get a smooth, even pour. We tried again and made sure we had all our cups lined up and a plastic spoon at the ready to help us pour and this time we got much better results. We waited with our fingers in the alginate for about seven minutes and then pulled them out of the mold. It was really cool how you could see all the details of the skin and the fingernail as well.

For the plaster, we had trouble mixing the water fully into the powder. We had a layer of water on top, with a much thicker plaster mixture on the bottom, so when we tried pouring it into the molds, it was alternately too lumpy or too watery. We did our best to dump the plaster out of the molds and back into the buckets so we could mix again, but I think somewhere along this process I must have collapsed part of my mold. When I came in the next day to remove my finger sculptures, one of them was missing the fingernail. I suspect that a lump of plaster got stuck toward the bottom and didn’t adhere to the shape of the mold.

A few days later I tried again and the process went much better. I was able to get smooth mixtures of the alginate and plaster and they poured into the cups in even layers with no lumps. The only issue I saw when I pulled the casts out were some small air bubbles by the fingernails.

Next, I spray painted with two coats of red paint and a glossy clear coat!

Cost Type	Cost	Price	Source	Quantity	Total
Materials	Alginate	$19.99/lb	Amazon	~ 1 lb	$19.99
	Plaster	$10.98/4 lbs	Home Depot	~1 lb	$2.75
	Screws	$9.95/196 screws	Home Depot	4	$0.20
Labor	Prototyping engineer	$37/hr	Bureau of Labor Statistics	1 hr	$37.00
				Total	$59.94