The production

For this week’s project, I had to make a wall hook. However, it was not just a regular wall hook, but one in the shape of my finger. To achieve this task, I had to make use of molding and casting methods. The first step consisted of measuring out equal parts of alginate to water. Alginate is a popular material used for molding. It is very popular in dentistry. After combining the two parts and stirring vigorously I inserted my fingers into the mold, which was just a regular cup. I then waited for 5 minutes before carefully wiggling my fingers and pulling them out of the mold. 

Next, I moved on to casting. For this step I had to mix approximately equal parts of water with one part of plaster. However, when I was mixing, I noticed that the mixture was still very stiff. Therefore, I decided to add water until the mixture was liquid enough to my judgement. I then continued to add the plaster mixture into the mold and inserted a screw on top, which was taped to the side of the cup to prevent it from sinking in. After waiting for 30 minutes the plaster had dried and it was time to remove the cast. I did this by carefully removing the cup and then slowly breaking away the alginate.

Finally, after doing another iteration, I had created to wall hooks from two fingers each. The only remaining step was to spray paint the fingers to create a more striking appearance. See pictures below.

Challenges

During the casting and molding process, extra care had to be given to some elements; when mixing the alginate with water, it is important to stir well-enough so that the alginate does not form lumps. One most also stir long enough for the alginate to slightly change color. When the color of the alginate changes back to its original, it is the right time to insert your fingers. During the casting step, it is important to slowly pour in the plaster so that air bubbles are avoided. If air bubbles are formed nonetheless you can try to solve this by carefully shaking the mold. I used this technique to rid the air bubbles from my second cast and it worked quite well.

Cost analysis

The average price of alginate is approximately $10 per kilogram. For each iteration I used about 250 grams, which would amount to $5 worth of alginate. Plaster goes at about $4 per kilogram, and because I made too much plaster both iterations, I used about 300 grams in total, which adds up to $1.20. In total, I spent about 1.5 hour on all of the assignment. At a minimum wage of $7.25, that adds $11 to the total charge. In total, the cost for these wall hooks is $8.60 per hook or $17.20 in total.