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
By Castin' Craft. Food safe silicon mold making material. It comes as two silly putty like materials. You select an even amount of each, knead them together for 60 seconds. You have about 2 minutes to work with the material. You form it around your model and let it solidify. It takes about 30 minutes. The finished product is very sturdy silicon, similar to calking but heavier. The box claims it can be used to to 400 degrees.
I found this extremely easy to work with. I used a precision kitchen scale to measure out the portions. I was not exact and it worked well. You can make your mold through several steps because new material sticks well to old material. However, you can get a line where the the batches meet. My hands were a bit oily feeling at the end, but clean. I made small chocolate molds and the material picked up even small features. One time I mixed 40 grams of each and that was a lot to work with at once. In the future I'd think carefully about where marks would be acceptable on my molds and apply the material in batches.
I bought 2 pounds at Tap Plastics for about $30 in January 2018.
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.