Storing your balloons
When you amass a large collection of balloons, as many enthusiasts do, you'll want to have a few tricks under your belt in order to keep them for as long as possible. Here are a few tips.
Storing inflated balloons
Those who want to stretch their balloons to their limits will often want to inflate and re-inflate to achieve the largest size. The best stretch a balloon can get is a good tight inflation, held for hours or days or longer. So when you're in the process of stretching a balloon with this method, you'll want to store it in an inflated state. Here are some important considerations.
Degradation. Rubber has many natural enemies, some of which live inside your house. The biggest is direct sunlight; next is probably ozone; water is another. Thus it follows that inflated balloons should be stored away from sunlight, in fact, the darker the better. Sunlight and ozone combine to oxidize the surface of the balloon, making it less shiny over time, and slightly thinner and weaker. Some oxidation is inevitable, but these are the steps you can take to slow down the process. In fact, some balloons are at their stretchiest (hence largest) after a little oxidation. Also, store the balloons somewhere with a relatively constant moisture level. Water vapor dissolves ever so slightly into latex, increasing its elasticity; but if the humidity suddenly drops, a balloon that was tightly inflated in humid conditions can lose that elasticity and pop. In other words: avoid bathrooms or breezeways. Temperature. Inflated balloons can be surprisingly responsive to temperature changes. A tightly inflated balloon blown up in the heat can shrink and become soft in the cool weather; conversely, a tightly inflated balloon blown up in cool weather can suddenly pop in warmer conditions. Helium, because of its greater coefficient of volumetric expansion, are more susceptible to these changes, even more so since the helium coming out of a tank is usually cooler than the surrounding air to begin with (thanks to Bernoulli's principle, as the pressure plummets, so does the temperature). So keep your stored inflated balloons at as constant a temperature as you can. More practical concerns. Don't store inflated balloons in with your sewing supplies. While you won't do anything that foolish, you may miss what amounts to veritable sewing-drawers full of tiny sharp points on any surface. Carpet is best suited to cradle your balloons; hardwood, tile, or linoleum floors aren't so great. Small sharp points, grains of sand, fingernail clippings, misplaced straight pins, any of these can lurk on your floor without your knowledge, just waiting to pop that awesome balloon you've been prestretching for days. In any case, vacuum the surface your balloons will sit on thoroughly before storing inflated balloons on them. Cover hard floors with a soft blanket or towel. Adhesion & cohesion. Balloons can and do stick to themselves and to each other, especially when they're inflated and especially in the presence of moisture. This leads to a couple points: Adhesion is a balloon sticking to itself. In inflated balloons, the biggest culprit is the knot with which the balloon is sealed. Balloons that are inflated by mouth will be moist on the inside near the neck, and when the balloon is tied, the latex of the knot can (and usually does) stick to itself. A little adhesion isn't so bad, but if it persists, an adhesion can tear the latex when it's pulled apart. If you can, use non-adhering knots such as the coin-knot to seal balloons if you're concerned about adhesion. Cohesion describes stored balloons sticking to each other. The one rule is: don't tightly pack your balloons! Give them room to breathe. Also, storing balloons tied in clusters can (and usually does) make the balloons stick to each other at the neck. You'll be able to tell if when you pull two balloons apart, you hear a little "tick" sound (or a loud "pop" sound if it's really stuck together). Store balloons individually. Another practical concern. If you're going to store tightly inflated balloons, you probably don't want to do it in your bedroom. Think about the rude awakening possibilities! If it's unavoidable (say you're living in a studio apartment), just be sure not to tightly inflate balloons that you're going to store overnight. Let a little air out before you go to bed, then blow it back in (and more) when you wake up. I've used this method to stretch many balloons to their maximum size over a period of a week or so. Storing uninflated balloons
The same rules apply to storing uninflated balloons, but are slightly less important, as everything will have a more profound effect on stretched latex than unstretched. Additionally, there are a few other concerns about adhesion you should think about:
Fresh-from-the-factory balloons have a thin layer of talc powder on the inside - it's what causes the bitter taste you sometimes get when you first put your lips on it. This thin layer is specifically designed to prevent balloons from sticking to themselves during shipping. Once you've blown up a balloon by mouth a few times, the talc will dissolve and be washed away by your condensed breath, so you can (if you want) re-dust the inside of your balloons with talcum powder. The best way to turn a balloon inside-out is to take the eraser end of a pencil and, holding the balloon lightly in your hand, press the drip-point end into the neck and out. In any case, make sure the inside of the balloon is relatively dry before shoving it back into the storage bin. Storing away from light, heat, humidity, and other extremes is always a plus. Some professional balloon twisters store their balloons in the refrigerator. Try not to pack your uninflated balloons too tightly, either, as this will make it easier for moisture in your storage container to cause balloons to stick together.