One way to make transparent or translucent plastic at home is to use a plastic casting resin mix. These come in two parts, the resin and a hardener. When mixed together they form a hard, rigid plastic. Casting resins are usually clear and colourless, but you can colour them using suitable dyes. Use a ready-made mould or make your own mould from silicone or latex. Another option is to make a soft, translucent plastic using starch, such as corn or potato starch. Use processed starch or extract starch from potatoes yourself. Colour the mix with food dyes.
Put on rubber gloves. Check that the mixing vessel and stick are clean and free from moisture. Ensure that your work area is well-ventilated.
Mix together the resin and hardener. The correct quantities vary between resin brands so follow the instructions and use the quantities recommended by the manufacturer. Do not mix up more resin than you need, as leftover resin mix will harden and become unusable. Stir in pigments a drop at a time until the desired shade and opacity is reached.
Pour in the resin mixture carefully into the mould. (Ensure that your mould is clean and dry beforehand.) Allow to cure according to the manufacturer's instructions.
Remove the plastic from the mould. Trim away unwanted areas and sand off any imperfections. (
Pour 4 1/2 tablespoons of cold water into the non-stick pan. Add one tablespoon of starch, a 1 teaspoon of white vinegar and one teaspoon of glycerine to the mixture. (If you have already prepared your own starch, just add 4 tablespoons of cold water instead of 4 1/2.) Add a drop or two of food colouring if you want a coloured translucent plastic. Stir the mixture well.
Place the pan containing the mixture over a low heat, stirring. When the mixture begins to thicken, turn the heat up to medium. Keep stirring.
Bring the mixture to a boil, stirring continuously. You will need to stir harder as the mixture thickens more. Keep boiling for approximately five minutes, or until the mixture has become a transparent rubbery gel.
Pour the warm plastic into a mould or onto a sheet of aluminium foil if you wish to make a plastic film. You can also model the plastic like clay once it has set a little. Leave the plastic to set in a warm dry place, or in a low oven if you wish to speed up the process.
Adding more glycerine to the potato plastic will make the finished material softer. Adding less will make it harder and more rigid.
Plastic resins give off strong fumes until they are fully cured. These fumes can irritate lungs, eyes and skin. Make sure your workspace is fully ventilated at all times. Keep pets and children away.