I found recipes for this on several YouTube channels. you can use it to make a mold, cast several times in it, then you can melt it and make a new mold.
Possible bonus: it shrinks if left in a dry area, so if you leave a mold in, say, Tucson for several months, you can cast items smaller than the original. My mold that made a 3cm pot six months ago now makes a 25mm pot. That’s 17% smaller. I suspect you could get greater shrinkage if you put more water in the original mix.
The blue pot is the original, yellow resin was cast right away, brown resin was cast several months later.
This recipe makes a little more than 2 tablespoons of mold stuff. You probably want to make four batches at once, to give you enough to work with. If you buy bulk gelatin, use 2 parts glycerin, 2 parts gelatin, and 1 part water. Any extra can be stored and melted in the microwave as needed. You can also melt and reuse a mold you don’t need any more.
Mix together well:
1 Tablespoon glycerine (from a drugstore)
1 packet gelatin (2.5 ounces, unflavored, no sugar–Knox brand, for example) (1 Tablespoon of bulk gelatin)
Then add 1/2 Tablespoon water.
*Heat in the microwave for 10 seconds, then stir.
Repeat from * 2 or 3 times, until mixture is consistent.
Optional: add food color.
Use right away, or remelt later. Refrigerate until cold and solid.
Great for resin; seems to take longer than silicone molds for the resin to fully set. The surface will be slightly rough, not glassy smooth like a good silicone mold.
I don’t think it would work well as a press mold, and water-based clay would probably be a disaster.
Food safe for chocolate and candy molds if you haven’t cast non-food stuff in it. Filling must be cool enough not to melt the gelatin (I think they said 140 degrees, test before committing).