To create my finger wall hooks I first needed to make the mold mixture. To make this mixture I mixed alginate and water in a plastic container as part of an in-class tutorial. With the mixture complete I placed my pointer finger in the mixture and let it solidify (~8 minutes). At this point I removed my finger leaving a negative mold of my finger.
With a mold made I was ready to cast a replicate of my finger. I needed a screw inside the final finger to be able to act as a wall hook so with tape I hung a screw from a popsicle stick down into the negative mold. I then mixed plaster of paris and water in a 2:1 ratio and poured that down into the mold. I left it to solidify overnight. The next day I removed the hardened finger and poured another mixture of plaster of paris to create a second identical finger. I did have a small hiccup in removing my second finger as the screw broke off during removal. To rectify this, I super glued the screw back onto the finger in the slot where it belonged.
With the two fingers casted, I then ensured it didn’t have any rough edges and then spray painted it green. To finish the project, I put a clear coat on the two fingers. I made sure my workspace was clean and the spray-paint cans were returned to their proper place after spraying (another student’s fingers are visible in the picture as they were working on theirs when I finished mine.)
Cost Table:
| Cost Type | Cost | Price | Source | Quantity | Total |
| Materials | Alginate | $11.99/680 grams | Hobbylobby.com | 0.05 | $0.58 |
| Plaster of paris | $7.99/1814 grams | Michaels.com | 0.04 | $0.32 | |
| Spray paint | $7.48/can | Homedepot.com | 1/20 | $0.37 | |
| Clear coat stain | $5.98/can | Homedepot.com | 1/20 | $0.30 | |
| Popsicle stick | $0.02/stick | Amazon.com | 1 | $0.02 | |
| Scotch tape | $2.98/roll | Homedepot.com | 1/180 | $0.02 | |
| Screws | $0.11/screw | Homedepot.com | 2 | $0.22 | |
| Labor | Mold maker | $27.46 | Ziprecruiter.com | 1/3 | $9.15 |
| Overhead | Facility Cost (Running water) | $288.43/year | Texasmovingusa.com | 1/365 | $0.79 |
| Quality Control | $13.00/hr | Zippia.com | 1/6 | $2.17 | |
| Design | Engineering and Development | $35/hr | Red Fox Innovations | 1/6 | $5.83 |
| Misc. | Waste and Scrap | $13.50/hr | Ziprecruiter.com | 1/6 | $2.25 |
| Total | $22.02 |
Cost Analysis:
To figure out the price I need to calculate the cost of materials used based of the ratios of aginate and plaster of paris compared to water. For the alginate mixture I used 33 grams of alginate and so that was used to calculate that I used 5% of the 680 grams of an alginate powder bag which equates to 58 cents. I made two plaster of paris mixtures both using 40 grams of powder which was 4% of the 1814 grams in a $7.99 tub (32 cents worth of powder used). For the spray paint and clear coat, I estimated I used 1/20 of the can for each can to paint and coat my fingers. I got the prices for the respective cans from home depot. The cost of screws, popsicle stick and tape were trivial and came from the websites of well-known vendors. For labor, I decided a mold maker would be the best for the job and so I found the average hourly salary of a mold maker on zip recruiter and calculated the price for a 20-minute job which seemed like a good estimate for how long it would take for an experienced mold caster to make the molds and pour the cast for this project. As both the alginate and plaster of paris mixtures used water I found the average water rate in Texas for one day to find the overhead of this project. Ensuring the fingers were properly cast (quality engineer), designing the color and finishing (engineering and development, and waste cleanup all took 10 minutes each and as such were calculated to cost 1/6 of the hourly rate for each position. My estimate for the total project cost for two fingers is $22.02. The materials for this project were very inexpensive and the bulk of the cost for this job came from labor and design.
