I am wondering if any chemists could suggest an additive I might use in gelatin when used as a binding agent that will slightly soften the gelatin when dry. Hopefully it would be something I could use to actually control the hardness. It has to be non toxic as it will be used for pets.
They used to use a mixture called composition back in the 19th century as a rubber substitute, for things like rollers for printing presses. The recipe I was given used a mixture of hide glue, molasses, and plaster of paris. I’ve since found others on the internet that generally don’t use the plaster (which seems to be used as binder/tempering agent), and which may substitute sugar for the molasses.
The mixture, aside from the plaster, looks edible. I’ve even found one site where they made such “composition” rollers out of melted Gummi Bears!