From Shrimp Maker Wiki
Mold Making Materials
Can be used to easily make a cast of your hand, your foot, or some other object. I used 1 pound of alginate in 7 cups of 80 degree water to make a cast of my hand. It set very quickly, but not too bad. Next time I would make the water cooler or add more to slow the setting. It has a pleasant smell.
I made a mold form from old cardboard, lined with a plastic supermarket bag. Not sure that I needed the bag; the alginate is very thick. One pound was enough to cover my hand to just beyond my wrist.
It turned gray/white in about 3 minutes and I was able to pull my hand free. All hair remained on my arm. Filled the form with plaster of Paris and the resulting cast was incredibly detailed.
- $15 on Amazon prime. 1lb (454g) Create-A-Mold Alginate Molding Powder by Casting Keepsakes
Mold Casting Materials
DAP Plaster of Paris
The box calls for one part water, two parts plaster of paris. When I did the first mold of my head the PoP seemed too thin so I added more powder. It took three days to completely dry. I thought that was due to the thickness of the part. Today I made a second mold and mixed it 1:2 as called for. It was thin when I poured it in but it appears to be setting more quickly.
There are two almost identical boxes of DAP PoP: Hobby and Home. According to James A Mason (good name) at DAP, The Hobby and Craft product is formulated to release easier from molds when used for casting. Application of a bond breaker material is still required when using the material for casting.