Flood your kid's birthday party venue with glitzy novelty balloons and allow their friends to each take one home when the party's over. Making your own helium-filled Mylar balloons is more inexpensive than buying individual balloons from street vendors or retail outlets. Make your kid's party special by buying in bulk while saving money. Purchase helium and a heat sealer when planning to make a lot of balloons. Some Mylar balloons are self-sealing, but heat-sealed balloons are longer lasting. Properly heat-sealed balloons can stay inflated for years.
Hold the neck of your Mylar balloon closed, once it is inflated fully, with your thumb and forefinger.
Slide your thumb and forefinger down the balloon neck, squeezing tightly to contain the helium. The key to getting a good seal is to make sure there are no creases or wrinkles in the balloon neck where you are joining the two pieces of Mylar together. Slide your finger and thumb down the neck without creating any tucks or folds in the material.
Close the heat sealer, on its lowest setting, around the neck of the balloon approximately 1/2 inch in from the flat open end. Maintain the pressure with your thumb and forefinger during the sealing process.
Keep the arm of the heat sealer closed for an extra three to five seconds after the light has gone out.
Move the balloon and make another seal a 1/4 inch further toward the open neck end. Keep thumb and forefinger in place throughout and again wait three to five seconds after the light goes out before opening the heat sealer. The pressure from inside the balloon can sometimes pop a single seal back open when you let go of the balloon. The second seal ensures the balloon stays sealed.
If you don't have a heat sealer, use an iron, a freezer bag sealer or a hair curling iron. Keep temperatures low when sealing with these appliances and expect to find some residue left on them from the balloons. Most heat sealers are also suitable for sealing plastic food bags -- check with the manufacturer. This is particularly useful for freezing purposes. Keep your heat sealer's sealing platform free of residue, dirt and dust for best performance.
Don't touch the heated part of your sealer when it is switched on and avoid brushing your clothes or body parts against the machine. Do not allow children to play with heat sealers.