I found this online. It says to pour onto a coffee can lid but I would pour it directly onto the textured mat that K8memphis suggested. I hope this is what you are looking for.
Things You'll Need
9 tbsp. water
Food coloring
Medium saucepan
3 envelopes unflavored gelatin
Canister lid with a rim
Spoon
Cookie cutters
Straw
Cooling rack
Instructions
1
Pour the water into the saucepan and add 5 to 7 drops of food coloring while heating on low.
2
Add all three gelatin envelopes and stir until the contents are fully dissolved -- approximately 30 seconds. Turn off the heat and let the mixture stand and cool slightly for 2 minutes so as not to melt the plastic lid.
3
Pour the thickened mixture into the lipped lid, e.g., a coffee canister lid, and flatten the air bubbles with a spoon. The layer of gelatin can be anywhere between 1/4 inch and 1 inch thick. Let it stand at room temperature for 30 to 45 minutes, depending on the thickness of the layer. The bendable plastic lid will allow you to easily turn out the thickened gelatin by pressing your thumbs into the back of the lid. Use cookie cutters to carve out shapes and a straw to poke holes for hanging.
4
Place the pliable shapes on the cooling sheet and allow them to cool and harden overnight.
