Shrink plastic starts off as a large, thin sheet. When heated, it shrinks, becoming thicker in the process. It is used for many craft projects, including jewelry making and scrapbooking. Commercial shrink plastic is available at craft stores, but it can be expensive and you only receive a few sheets. You can make your own shrink plastic from recycled materials. Take-out boxes, deli and bakery containers, and other packaging can be used for your creations.
Look for the number 6 in the center of the recycle symbol on your plastic container. The recycle symbol is made up of 3 arrows in a triangle shape and is usually imprinted on the container. Only use number 6 plastic.
Cut out the desired shape from a flat piece of the plastic, removing any rims or uneven parts. The plastic will shrink to nearly half the size when baked, so make your shape larger than you need.
Punch holes in the plastic if you will be using the plastic to make charms or jewelry. The holes must be punched before baking.
Rough up one side of the plastic with fine grit sandpaper then draw your design on the rough side.
Place the completed plastic shapes on parchment paper on top a cookie sheet. Place in a preheated oven and bake at 250 degrees Fahrenheit. Leave the oven door open and flatten them with the spatula if they curl too much while baking. It should take 1 to 3 minutes for them to complete shrinking.
Spray the completed shrink plastic with an acrylic sealer on the colored side to make it waterproof.