The first piñata I made was for a Star Wars themed birthday party. I barely knew what a piñata was, much less knew how they were supposed to be made, but figured making something that could be smashed open couldn't be hard. I cut out a bunch of hexagons and pentagons out of thick cardboard and assembled a truncated icosahedron with the help of lots of masking tape. Unsure whether that would be sufficiently strong to withstand the depredations of a pack of armed and enthusiastic eight-year olds, I papier-mached the outside, spray painted it grey and hung it from a tree as the Death Star. The Jedi younglings swung at it with gusto and barely scratched the surface. We equipped them with ever heavier weaponry, and it finally took sustained beating with a heavy broomstick until they were all nearly exhausted, whereupon it split slightly; frenzied tearing and kicking eventually freed the candy. This mayhem was all so much fun that nearly-indestructible, geometrical piñata have become a feature of our kids' birthday parties. An octopus with a cuboctahedral head for a pool party... a big top tent made of a capped hexagonal prism for a circus party... you get the picture. This year, I made another truncated icosahedron (aka buckyball aka C60 aka soccer ball), this time extended with another five hexagons (to mimic another allotrope of carbon, C70), as a dragon's egg for my son's Harry Potter themed party.
Step 1: You'll Need...
Thick cardboard ~ Tissue paper ~ Masking tape ~ Glue ~ Scissors ~ Paint ~ Protractor ~ Ruler
Step 2: Assembly Part I
Cut the cardboard into 25 hexagons and 12 pentagons. Edge length should be the same for both shapes; I used a hexagonal tile as a template then measured the pentagon using these dimensions.
Tape five hexagons to one pentagon, and form into a bowl by taping the hexagon edges together. The more tape you use, the stronger the pinata will be. Keep adding pentagons and hexagons, until you have 6 pentagons, all surrounded completely by hexagons. Every vertex includes 2 hexagons and one pentagon. You should have a hemisphere.
Step 3: Assembly Part II
Add five more hexagons into the "gaps" in your hemisphere. Assemble one pentagon and five hexagons into another bowl, and tape to the elongated hemisphere from Part I. You should have five pentagonal holes left.
Step 4: Assembly Part III
Unless you've been amazingly accurate, the holes won't be perfectly pentagonal. No problem; just trim the pentagons to fit, and tape four of them in place. Add candy (forgetting to do this is embarrassing). Tape the hole up.
Step 5: Assembly Part IV
Papier mache the outside. Just dilute some white glue (PVA), paint it on messily, and drape strips of tissue paper over it. Rough is fine - the egg will just look more leathery. Leave to dry overnight somewhere warm.
Step 6: Paint
What color is a dragon's egg? Whatever color you want it to be; this one was from a Gryffindor dragon, well known to produce red-and-gold eggs. We painted it red, let it dry, and followed up by dry-brushing it with gold paint (use a dry brush with hardly any paint on it, and tickle the surface; the paint will come off on the raised parts only, and bring out the texture nicely).
Step 7: Smash It
The kids at this party had all read their Harry Potter, but thought throwing it off the deck would be more fun than soaking it in a bathtub. They were right - it took them three throws from about 12 ft up down on to a concrete driveway, and while the caramel cremes were fine, half of the hard candies were pulverized...
Extra for experts: there is a properly egg-shaped buckyball - C84, with two adjacent pentagons - for those who value authenticity over speed of assembly!