Over the past week, I’ve been working on creating two casts of my finger using molding and casting techniques. To begin, I made a mold of my finger using alginate. I mixed 33g of alginate with 125g of water, stirring for about 4 minutes until the mixture was smooth. Once the mixture reached the right consistency, I carefully inserted my finger and allowed the mold to set.
Next, I moved on to casting the mold. I prepared a plaster of Paris mix, using a 2:1 ratio of plaster to water. After thoroughly mixing, I poured the plaster into the alginate mold, ensuring it filled the entire cavity. I let the plaster set for 5 hours before carefully demolding the finger from the cast.
Finally, I spray-painted the casts to complete the process, giving them a finished look.
| Cost Type | Cost | Price | Source | Quantity | Total |
| Materials | Alginate | $9.99/4 lbs | Target | 1 | $9.99 |
| Plaster of Paris | $6.64/4 lbs | Home depot | 1 | $6.64 | |
| Spray paint | $5.98/can | Walmart | 2 | $11.96 | |
| Labor | Molder | $16/h | Zip recruiter | 1h | $16 |
| Prototyping Engineer (You!) | $36/h | Zip recruiter | 1h | $36 | |
| Overhead | Facility Cost | $75/h | Peerspace | 1h | $75 |
Total: $155.59
The total cost of molding and casting two finger prints was $155.59, which seemed high due to the bulk material purchases and labor costs involved. I used alginate and plaster of Paris, both sold in 4 lb packages, which resulted in paying for more material than I needed for just two molds. Additionally, the involvement of a molder and prototyping engineer added labor costs, further increasing the price. However, if I were to create more casts, the cost of materials and labor would be spread across multiple units, significantly reducing the cost per finger. Since both the alginate and plaster are used in larger quantities, making more molds would make the process much more cost-effective.
Estinamting the cost of one finger (in duplicate): 77.80$
Estimating the cost for 30 pieces:
Cost per mold for alginate: 0.33$
Cost per mold for plaster: 0.22$
Cost per mold for spray paint: 0.40$
Cost molder per finger: 0.53$
Cost engineer: 1.2$
Facility cost: 2.5$
Total cost (in batch of 30): 5.18
