Shrink plastic charms are one of those crafts that feel a little like magic to children. You draw on a thin, flexible sheet, pop it in the oven, and a few minutes later it curls, shrinks and flattens into a thick, hard little charm. Add a keyring or a bag clip and your child has a one-of-a-kind keychain they designed themselves.
This guide walks parents through the whole process: choosing the film, drawing and colouring, baking, and sealing the finished pieces so they last. It is about making your own, not buying ready-made keychains, and it works well for a rainy weekend afternoon or a school holiday project.
What Shrink Plastic Is and How It Works
Shrink plastic, sometimes sold as shrink film or by brand names like “Shrinky Dinks”, is a thin sheet of plastic that has been stretched during manufacturing. When you heat it, the plastic relaxes back towards its original size. It shrinks in width and length and becomes much thicker and stiffer.
As a rough guide, most shrink films end up noticeably smaller than the original drawing, often around a third of the size, and several times thicker. The exact shrink ratio varies by brand and type, so always check the instructions on the pack you buy.
You will usually find it in a few types:
- Clear or frosted film, which you can colour with pencils on the rough side.
- White film, which gives bright, opaque colours.
- Inkjet-printable film, which lets you print designs at home.
- Coloured or black film, for special effects.
In Singapore, shrink plastic sheets are commonly available at art and craft supply shops, larger bookstores with craft sections, and online marketplaces. Kits for children often include pre-printed outlines and keyring hardware.
What You Need Before You Start
Gather everything first, because the baking step moves quickly.
- Shrink plastic sheets
- Coloured pencils, permanent markers or acrylic paint pens (check what your film recommends)
- Fine sandpaper, if your film is smooth and needs a rougher surface for pencils
- Scissors, plus a hole punch
- An oven or toaster oven, with baking paper or parchment
- A flat, heatproof object like a ceramic tile, wooden spatula or a heavy book wrapped in baking paper for pressing
- Keyrings, jump rings, bag clips or phone straps
- A sealant, such as clear nail varnish, a craft sealer or UV resin (for older children or adults)
Many HDB kitchens have a compact toaster oven rather than a full oven. That is usually fine, but keep pieces small so they do not touch the heating element as they curl.
Step by Step: Drawing, Baking and Sealing
1. Prepare the surface. If you are using coloured pencils on smooth film, lightly sand one side in both directions until it looks frosted. This helps the colour stick. Many films come pre-sanded on one side.
2. Draw your design big. Remember everything will shrink, so draw larger than you want the final charm to be. Thin lines become very fine, so outline in a darker marker. Colours also intensify after baking, so go lighter than you think.
3. Cut it out. Leave a small border around the drawing. Rounded shapes work better than sharp points, which can become spiky after shrinking.
4. Punch the hole before baking. This is the step people forget. Once baked, the plastic is too hard to punch easily. Use a standard hole punch, and remember the hole will shrink too.
5. Bake. Preheat your oven to the temperature on the pack, place pieces on baking paper, and watch closely. The plastic will curl dramatically, sometimes folding over itself, then flatten out. This only takes a few minutes. Do not take it out while it is still curled.
6. Press flat. As soon as it flattens, remove the tray using oven gloves and immediately press the pieces with your tile or spatula for a few seconds to keep them perfectly flat.
7. Cool and seal. Let pieces cool completely. Then coat with clear sealant to protect the colours from rubbing off and from humidity. Let it dry fully before attaching hardware.
8. Add the hardware. Open a jump ring with two pairs of pliers, thread it through the hole, add the keyring or clip, and close it.
Choosing Colouring Tools and Finishes
Different colouring tools behave differently on shrink plastic. Here is a quick comparison to help you pick.
| Tool | Best on | Result after baking | Tips |
|---|---|---|---|
| Coloured pencils | Sanded or frosted film | Soft, intensified colour | Shade lightly, colours darken a lot |
| Permanent markers | Smooth or frosted film | Bold, bright lines | Good for outlines; may smudge if handled before baking |
| Acrylic paint pens | Most films | Opaque, vivid colour | Let paint dry completely before baking |
| Inkjet printing | Printable shrink film | Detailed, photo-like images | Follow the pack’s printer settings; seal well afterwards |
Avoid water-based markers on unsanded film, as they tend to bead up and smear. Test a small scrap first if you are not sure how your tools and film work together.
Safety Tips for Parents
Shrink plastic is a popular children’s craft, but the oven step should always be handled by an adult or with close supervision.
- Adults handle the oven. Children can watch through the glass, which is half the fun.
- Ventilate the kitchen. Heating plastic can release a smell. Open a window and turn on the hood fan, and follow the ventilation advice on the pack.
- Use the right temperature. Overheating can scorch the plastic. Stick to the manufacturer’s instructions.
- Let pieces cool. Freshly baked charms are very hot, even though they look harmless.
- Small parts warning. Finished charms, jump rings and keyring parts are choking hazards for toddlers. Keep them away from very young children and siblings.
- Sealant use. Nail varnish, spray sealers and UV resin should be used by adults or older children in a ventilated area, following the product label.
Only use shrink film sold specifically for crafting. Random plastic packaging is not designed to shrink evenly and may not be safe to heat at home.
Ideas for Charms Your Kids Will Love
Once your child gets the hang of it, the possibilities open up quickly.
- Name tags for school bags, with their name and a favourite animal
- Mini versions of their own drawings, a lovely keepsake from a certain age
- Pet portraits from a photo printed onto inkjet film
- Matching friendship charms to give to classmates
- Festive ornaments for Christmas, Hari Raya, Deepavali or Chinese New Year
- Zip pulls, phone charms and badge pins with a glued-on brooch back
If your child already enjoys collecting keychains, making their own can become a lovely companion hobby. Our guide to collecting keychains and fridge magnets in Singapore covers the buying and displaying side.
Troubleshooting Common Problems
- Charm stuck to itself while curling: It was likely too thin and long. Try a chunkier shape, or gently separate it with a wooden skewer while still in the oven and let it flatten.
- Uneven shrinking: Your oven may have hot spots. Rotate the tray or bake pieces one at a time.
- Colour rubbing off: Seal with a clear coat after baking.
- Hole too small: Use a bigger punch next time, as holes shrink too.
Reducing Waste While Crafting
Shrink plastic is still plastic, so it is worth using it thoughtfully. Plan designs to fit several on one sheet, keep larger offcuts for small charms and buttons, and make pieces your family will actually use. You can read more about how Singapore handles plastic waste in our guide to recycling plastics in Singapore, and note that most mixed craft scraps are better kept for future projects than placed in the blue recycling bin.
Shrink plastic charms are cheap, quick and endlessly creative. With a sheet of film, some pencils and an adult on oven duty, your kids can turn a doodle into something they will carry around every day.