I just wanted a rough estimate on how much paper mache i would be using for my project. For this project i will be creating a big pinata. Instead of using a balloon i will be using an exercise ball or something around that size. Thank you for your time.
Answer from Piñata Boy
The short answer is that if you’re using flour and water to make the papier mâché mix, expect to use a full 5 lb bag of flour. If your exercise ball is under 20 inches in diameter you probably won’t use the whole bag, but if it’s much larger than 20 inches you might need even more.
A large piñata like this has to be built over the course of many sessions — you have to apply some papier mâché, let it dry, apply some more, let it dry, and so on. Most likely you won’t be able to cover the entire surface of the ball at one time, because the weight of the wet papier mâché on a piñata that big stretches the wet newspaper and everything begins to sag. So expect to apply papier mâché to the ball in partial layers over the course of many sessions (covering 1/2 to 2/3 of the ball at a time), which depending on your schedule and the weather, will take at least a few days.
You will want to save any leftover papier mâché mix between sessions. The flour/water mixture ferments fairly quickly (you will know it by the smell), so I store my leftovers in the refrigerator between sessions. When I’m ready for another round I add some hot water and some fresh flour to warm up the mixture.
One thing to keep in mind with large piñatas is that the surface area increases quickly as the diameter grows larger. For example, a spherical piñata with a 12-inch diameter has a surface area of a little more than 3 square feet. You can imagine that as a flat surface 1 foot long and 3 feet wide — that’s the amount of surface you have to cover with papier mâché, and then decorate. If your piñata has a 16 inch diameter instead, the surface area increases to 5.5 square feet, and if your piñata has an 18 inch diameter, the surface area expands to more than 7 square feet. In addition to the surface area itself, a larger piñata requires more layers of papier mâché to strengthen the walls and prevent them from collapsing under their own weight. So while 3 layers of papier mâché are plenty for a 12-inch diameter piñata, you will need to apply 4 layers minimum on an 18-inch diameter piñata. That means the total surface area being covered in papier mâché more than triples from 9 square feet to over 28 square feet, when the diameter increases from 12 inches to 18. Increasing the diameter adds a lot of time to both the construction and the decorating of the piñata, so plan your schedule accordingly.
If you want to know how much surface area you’ll have on your piñata, measure the circumference around the outside of the ball in inches, then use the formula Surface area in square feet = (circumference x circumference) ÷ 452.