Last spring, mechanical engineer Jim Smith wanted to go kayaking near his home in South Carolina. The only problem was he didn’t have a kayak. Most of us would have headed to a sporting goods store to buy or rent a boat, but Smith decided to print one.

He designed a 5.5 meter (18 foot)-long kayak on his computer. Then he used a 3-D printer in his garage to print 28 plastic pieces, which he assembled into a complete, functioning boat. It cost half the price of a similar store-bought kayak. 

Smith is a mechanical engineer at 3D Systems, a company based in Rock Hill, South Carolina, that sells 3-D printers and 3-D printed products. But experts like Smith aren’t the only ones making amazing creations with 3-D printers. In the past five years, 3-D printing has gone mainstream.

You’re probably familiar with printers that use ink to create text on paper, but 3-D printers work differently. Many of them use colorful plastic as their printing material. “It works just like a hot glue gun,” says Smith, who designed and built a 3-D printer called the Cube. The machine pushes spaghetti-like strings of plastic through heated nozzles, melting the plastic and squeezing it onto a platform below (see How 3-D Printers Work). The machine adds layer after layer onto the platform to build the object.

Plastic isn’t the only material used in 3-D printers. Some use metal, ceramic, glass, or wood. It’s even possible to print food. “We have printers that print powdered sugar mixtures in different colors and flavors,” says Smith. The result: 3-D printed candy. This fall, 3D Systems opened a culinary lab in Los Angeles where chefs and engineers can work together to explore the future of food. 

You don’t have to look far to find 3-D printed objects around you. The airplane manufacturer Boeing estimates that more than 20,000 3-D printed parts currently fly on its planes. And while some objects come out of 3-D printers ready to use, others are prototypes. These test models allow people to inexpensively and quickly see what their designs will look like in real life, and then make improvements before creating their finished products. Many of the products on store shelves—from sneakers to laundry detergent bottles—likely started out as a 3-D printed prototype. Even architects print miniature versions of buildings they’ve designed to see how they look before starting construction.

3-D printing is improving people’s lives. Doctors use the printers to create metal implants, like jawbones, rib cages, and hips. They can even print replicas of patients’ hearts and brains to practice on before performing complicated surgeries. 

The printers offer a way to make medical devices more quickly and cheaply. That’s good news for kids who need prostheses, or artificial limbs, because they have to replace them often as their bodies grow. Thousands of people around the world are getting prosthetic hands from e-NABLE, a community of more than 3,000 volunteers who make 3-D printed hands for those in need. A typical prosthetic hand can cost up to $10,000, but the ones by e-NABLE can be downloaded, printed, and assembled for less than $50.

 All e-NABLE hand designs are free to download, and assembly is easy. Girl Scout and Boy Scout troops have assembled hands that have been distributed to people in impoverished communities and refugees worldwide. Recently, e-NABLE partnered with 3D Systems to create more-advanced prosthetics. 

3-D printers are even helping astronauts. Last year, NASA tested a 3-D printer aboard the International Space Station, a laboratory that orbits Earth, to see if it could work in zero gravity. Astronauts successfully printed a total of 20 objects, including a wrench and a storage container. Having a 3-D printer on the space station could one day eliminate the need to send spacecraft to resupply the orbiting laboratory. Those missions require months of planning and can cost tens of millions of dollars. 

Scientists hope that someday, astronauts will be able to print food, tools, and other items that they’d need during lengthy space missions to places like Mars and beyond. NASA scientists are already experimenting with a 3-D printer that uses powdered ingredients to make pizza.

Back on Earth, Smith thinks that someday everyone will have a 3-D printer in their home to make anything from food to furniture. “Printing complete working devices, that’s really the future,” says Hod Lipson, the director of the Creative Machines Lab at Cornell University in New York. “If you need a new remote control, for example, you will be able to just download and print.”