If you're planning a themed party, making your own plaster figures is a great way to stretch your budget and get the kids excited days before the party even starts. It's genuinely easy, needs only a few supplies, and the "reveal" moment when you peel back the mold never gets old, for kids or adults. Better yet, once you've got the basics down, you can reuse the same process for any theme, just swap the mold.
We've used this for birthday parties, Halloween, travel activities, and even just a rainy afternoon at home — the process is exactly the same every time, only the mold changes.
What you'll need
- A reusable silicone mold in your party theme (see mold ideas by theme below)
- Plaster of Paris or craft casting plaster (affiliate link)
- A mixing container and something to stir with (a glass jug is ideal, since dried residue wipes off easily with a kitchen towel — but any old jug and spoon will do)
- Water
- A measuring cup
- A palette knife or old spoon for scraping and leveling
- Disposable gloves (optional, but helpful for small hands)
- A tray or board to keep everything contained while it sets
Tip: check your mold's product page for how many pours it takes and how much plaster each cavity needs, so you don't run short mid-batch.
Safety notes before you start
- Work in a well-ventilated room, since plaster dust can be irritating to breathe.
- Never pour leftover plaster down the sink, as it sets hard and can clog your pipes. A glass jug is preferable for mixing, since any residual plaster wipes off easily with a kitchen towel once dry — but any container works, just let leftovers dry out fully before disposing of the solid lump.
- Plaster heats up slightly as it sets. It's not dangerous, but let kids know so they're not startled.
- Supervise young children around the dry plaster powder, since it shouldn't be inhaled or eaten.
Step-by-step
Step 1: Prepare your workspace
Lay a tray or old towel down to catch spills. Set your mold flat and level on the tray. Silicone molds flex and bend when picked up on their own, so it's useful to place them on a hard surface in case you need to move them elsewhere before they've fully hardened — I've broken more figures than I can count trying to move a mold that wasn't fully cured.
Step 2: Measure your water and plaster
Check your plaster's instructions for the water-to-plaster ratio (it varies by brand). Pour the water into your mixing container first.
Step 3: Add the plaster
Sprinkle the plaster powder into the water gradually rather than dumping it all in at once, which helps avoid lumps.
Step 4: Mix thoroughly
Stir until it's a smooth, lump-free consistency, roughly like heavy cream, making sure to scrape down the sides and bottom so there's no dry plaster clinging to the jug. Don't worry about timing this one — it's more about the texture than the clock, so this is a great step to let kids take their time with under supervision.
Step 5: Pour into the mold
Fill each cavity slowly, tapping the mold gently on the table a few times as you go to release any trapped air bubbles. You'll need steady hands for this step when working with silicone molds.
Step 6: Level it off
If you've filled the mold to the top, level it off using your palette knife or an old card to scrape away any excess plaster, so the backs of your figures sit flat. (If your mold isn't filled all the way, you can skip this step.)
Step 7: Let it set
Leave undisturbed for approximately 1–2 hours, following your plaster's instructions. Don't rush this part, since figures can break if removed too early. Gently feel the mold to check that the plaster has hardened — if you have the time, it's worth waiting a couple of extra hours to stay on the safe side. Keep in mind that temperature and relative humidity can have a big impact on timing, so cure time may vary depending on conditions.
Step 8: Release the figures
Gently flex the silicone mold to loosen each figure, then carefully push it out from the back. This is the fun "reveal" moment, and it's worth letting kids do this part themselves.
Step 9: Let them fully dry
Even once set, figures are often still slightly damp inside. Leave them somewhere dry for a day before painting, so the paint takes properly.
Letting kids help
This is a great activity to do together a few days before the party. Kids can help measure, stir, pour (with supervision), and especially enjoy releasing the figures from the mold. It's a good calmer activity that also builds excitement for the party itself, since they're literally making the party favors they'll take home later. For younger children, let an adult handle the hot-ish, wet plaster stage and hand the "reveal" step to the kids.
It really is an easy process for kids to get involved in — even with a baby creating chaos nearby, we managed just fine.
Troubleshooting
- Bubbles or holes in the figure: Tap the mold more firmly after pouring, or gently tap out air bubbles with a toothpick before it sets.
- Figure breaks when removing it: It likely needed more time to cure. Extend your set time next batch.
- Rough or powdery surface: Usually means the plaster-to-water ratio was slightly off. Double-check your brand's instructions and measure carefully rather than estimating.
- Mold discoloring or degrading over time: Rinse and fully dry your mold between uses, and avoid very hot water, which can shorten a silicone mold's lifespan.
What's next
Once your figures are dry, they're ready to paint. Acrylic paint gives the best finish, but any kids' water-based paint works just fine. Markers work too — really, any marker on hand will do, though acrylic paint markers hold up especially well and give a cleaner finish.
Bonus: a travel activity
These figures aren't just for parties — they're sturdy enough to travel with too. We've made them to keep our kids entertained on plane trips, coloring them in with ordinary markers along the way. If you've got a long flight or car ride coming up, pre-casting a few blank figures and packing a set of markers makes for an easy, mess-free activity kids can do on the tray table.
Check our dinosaur party favors guide for more packaging tips, or our dinosaur party games article for more ways to use spare figures, including in a fossil dig.