I have been in the balloon inflation business for over 45 years, and I must say, I think I could be considered an expert on the subject. I know just how big to blow up a latex balloon and I know the history behind the foil balloon and how they “magically” seal themselves. So allow me to share some of my balloon knowledge with you, gentle readers.
First of all, balloons can be filled with air or with helium. When they are filled with helium, they will float. Helium is a “noble” gas, and it is not explosive, but it can be harmful if you breathe it in. It is lighter than regular air, because the molecules are very small, but because the molecules are small, they can penetrate other substances, like latex. That is why latex balloons do not float forever. Over time, the helium leaks out through the balloon and your latex balloons will fall down after a few hours. Foil, or mylar, balloons are made from a different substance that prevents the helium from escaping, so they float much longer than latex balloons. Sometimes for days or even weeks!
Balloons are affected by the temperature of the air around them, so if you blow up your latex balloons in an air conditioned house or business, and then take them outside on a hot day, they may pop, because the helium expands rapidly inside the balloon. Latex balloons will also become “chalky” in hot outdoor conditions. Conditions like wind and heat will dramatically decrease the float time of latex balloons. Products like Hi Float™ can improve the float time of your helium filled latex balloons.
Helium comes compressed in “tanks” and can be purchased in small quantities at discount stores, or from compressed gas companies when you need a large volume to inflate a large quantity of balloons. A 12” latex balloon or foil balloon requires about .5 cubic foot of helium, so you would need about 242 cubic feet of helium to inflate 500 balloons.
If you fill latex or foil balloons with air, they will not float. We recommend using a cool air inflator for best results. Warm air from a human’s lungs will cool to room temperature and your balloons will shrink. You may want to consider having your balloons printed upside down if you are going to hang your air-filled balloons from the ceiling. You can also use balloon cups and sticks to display air-filled balloons.