Shrink dinks have been around since 1973 but became greatly popular in the ‘80s. From that time, they’ve had kids creating crafty art on flexible sheets of plastic. When heated in the oven, these sheets of plastic shrink into small hard pieces without altering their shape and color.
How Shrinky Dinks Work
Shrink dinks have been used by both kids and adults with a crafty charm, for more than four decades now, to create designs. These popular arts-and-crafts are used to create colorful art, Christmas tree ornaments, key chains, zipper pulls, pet identification tags, or even jewelry.
How they work is pretty simple. You simply color a sheet of special plastic to make a design and then pop the plastic into a preheated oven. After a couple of minutes the plastic curls, “magically” shrinks and then flattens out into its previous shape only that now the shape is smaller and more rigid.
The entertainment is more in creating the shrink dinks than playing with them. Kids have so much fun as they color pictures of their favorite cartoon characters onto the sheets of plastics then watching them crinkle up in the oven and mysteriously flatten out again.
The plastic film bends, warps, curls, and slowly flattens right before your eyes. As much as it breaks my heart to say this, there’s no magic behind the toys’ quirky behavior. Keep reading to find out more about how much shrink dinks shrink and the reason behind it.
How To Make Shrinky Dinks
The shrink dinks business is a global affair that nets in millions of dollars annually. There are many manufacturers who sell pre-made shrink dink designs of Disney princesses, cartoon characters, and educational kits for kids for learning letters and numbers.
Despite the fact that you can purchase the shrinky dinks from retailers and online commercial sites, it’s more fun to make your own homemade versions of the designs. It’s a very easy project. Here are the items that you’ll need:
- Permanent markers or colored pencils
- Regular hole punch
- #6 plastic
- Scissors to cut the plastic
- Cookie sheet lined with a double layer of aluminum foil or parchment paper
Typically, you first have to preheat the oven to 325-350 degrees Fahrenheit
Secondly, cut out the shapes out of the plastic. If you would like to attach the shrinky dink to something, later on, don’t forget to punch a hole into it (this has to be done before baking).
Then color one side of the special plastic sheets using the permanent marker. The color will become more intense after shrinking
Next, place the plastic on the cookie sheet in between the layers of parchment paper and bake for about 2-3 minutes.
Watch the oven closely. The shrink dinks will curl up but then flatten out after. Once they have flattened out, bake for another 30 seconds.
Keep the windows open to let out the fumes that are produced
No matter what theme they follow, all shrinky dinks have one thing common– the shrinking sheets of plastic. When popped in the oven, the shrink dinks shrink down to approximately a third of their original size and become almost nine times thicker. The result is a rigid material that’s quite long lasting and may be used for quite a number of projects.
The magic of the plastic is dependent on the shape-altering properties of a special plastic as we’re going to mention in the next part. Without these properties, the plastic would simply burn leaving a cloud of gases in the oven.
The special plastic that is used is by nature polystyrene. Polystyrene has some very distinct properties. It’s light, transparent, and rigid at room temperature but melts when heated to temperatures above 350 degrees Fahrenheit. This way it can be manipulated into various shapes easily.
Polystyrene contains disorderly polymer chains that are bunched up and randomly clumped together. With heating, the chains undergo rolling and cooling forcing them to straighten out and get into a more orderly configuration.
The plastic sheets used to make shrinky dinks are the same stuff as recycled plastic #6. Plastic #6 is commonly used for clear clamshell containers that are used in many cafeterias. As they’re being manufactured, the polystyrene sheets are heated, rolled out into thin sheets and then cooled rapidly so that they don’t shrink.
In spite of all the warping and shape-shifting that the plastic goes through, when the shrinky dinks finally flatten out, the details of the original art remains.
Application in Science
It’s quite uncommon for items popularly used as kids’ toys and packaging material to make their way into labs. Shrinky dinks have moved beyond their reputation as kids’ toy to finding practical applications by scientists in different fields.
Thanks to the shrinking properties of polystyrene, it has been applied in many projects. In some, it’s been used as a tool that could potentially help solve very serious problems. For example, in nanotechnology, scientists are looking to manipulate the polystyrene with nano-patterns printed on it and used in the manufacture of solar cells, chemical sensors, and high-density displays. Printing those designs on shrinky dinks doesn’t take as much time and is cost-effective as compared to using other materials like glass. The scientists can make as many copies of the test pattern as they wish.
Again, these polymer sheets are used to make microfluidic devices by etching microfluidic patterns on polystyrene. When the sheets shrink, the pattern that’s drawn/written on them bulges and becomes more pronounced. These etchings are perfect for studies that require very minute samples of body fluids. These devices are a quick and inexpensive way to test for ailments, culture cells, and determine the effectiveness of drugs.
Every now and then, toymakers stumble onto ideas that turn out to be significantly successful products. This happens when toy time and serious experiments interest happen and accidentally create scientific breakthroughs. The toys then become cultural icons that span generations. Shrinky dinks are one of these products.