In the past, balloons were made from dried animal bladders, but now, they’re mostly all latex. They may not be exciting by themselves, but the process of making them is an entirely different story. To start things off, the latex is mixed with dye for 16 hours, and while that happens, balloon moldings are dipped in a chemical that attracts latex, then into the material itself.
The balloons then go through multiple physical and chemical processes before going through stress testing with an air faucet-like machine. Thanks to the rubber’s elasticity, these balloons are volume adjustable. Starting in the late 1970s, some more expensive foil balloons made of thin, non-stretchable, less permeable metalzsed films such as Mylar (BoPET) started being produced. What sets these apart from the latex ones is the ability to print color pictures and patterns on them as well as it being able to keep the helium gas from escaping for several weeks.