Foil/Mylar Balloons FAQ


What are foil balloons?
Foil balloons look like shiny silver metal when plain, although they are often printed. Unlike latex balloons, foil balloons are not porous, so air does not leak out of them easily, as long as they are properly sealed. Foil balloons are also not biodegradable, as they're made from synthetic materials.

How long will a foil balloon remain floating when inflated with helium? 
Our 17 inch foil balloons can float perfectly around 3-4 days before the balloon starts to deflate slightly. Our selection of 40 inch foil balloons will float perfectly around 10 days before the same process starts to happen. Both the 17 inch and 40 inch foil balloon will then last another 1-2 weeks in this condition and then progressively deflate further. Generally, 9 inch foil balloons are designed only to be inflated with air. 

How long will a foil balloon remain inflated when filled with air? 
When filled with air, the foil balloon will not float and will need a balloon cup and stick to hold the balloon up. The 17 inch and 40 inch foil balloons will remain inflated for approximately 1 month before it starts to deflate, while the mini 9 inch foil balloons can remain inflated for approximately 2 years. 

What size and types of foil balloons are available?
We sell small 9 inch, medium 14 inch and large 40 inch foil balloons for every occasion, including birthdays, baby showers, Valentine’s Day and more. See the complete range here.

What is a foil balloon made of? 
Foil balloons are made of nylon that is covered with a layer of aluminium. These materials are specially coated to give the balloon their foil-like appearance. They do not carry the risk of allergic reaction. 

How do I seal a foil balloon?
For self-sealing foil balloons, remove the nozzle from the foil balloon and press the valve flat to seal. For 9 inch foil balloons, a heat sealer is required. To ensure a tight seal, lay the tail of the foil balloon over the bar, making sure there are no creases in the material before application. A correctly inflated foil balloon should be tight with uniformly spaced creases along the seam.

Can I refill a foil balloon?
Foil balloons can be refilled if they have a self-sealing valve. Our 9 inch foil balloons do not have a self-sealing valve and needs to be heat sealed. Our 17 inch and 40 inch foil balloons can be refilled because they have a self-sealing valve. The 17 inch and 40 inch foil balloons can be re-inflated 2 or 3 times before the valve becomes unreliable.

How do I inflate a small sized foil balloon? 
All 9 inch foil balloons are designed exclusively for air inflation as they cannot hold enough helium to float. Small foil balloons are made with a valve inside the tail at the bottom of the balloon. The valve has to be opened to inflate or deflate the balloon. We suggest pushing a drinking straw gently up the stem until you feel resistance, that's the valve. Push slightly past the valve to establish an airway. Use your fingers to seal the balloon around the straw. You can then inflate the balloon by blowing into the end of the straw. If you have a hand operated balloon air pump, you don't need to use a straw. Insert the nozzle into the stem and again seal the balloon around it with your fingers. The pressure from an air pump will automatically open the valve as you inflate it.

Why do foil balloons look like they are deflating in the cold? 
The helium gas starts to contract around the temperature of 50-45 degrees and will decrease in volume. Once the balloon is in a warmer place the balloon will coming back to its normal size.



Do balloons come inflated?
No, all our balloons are packed deflated and need to be inflated with an air balloon pump or helium tank.

How do I know when the balloon is inflated to the correct size?
Our latex balloons are designed to be 12 inches (approximately 30cm) in diameter when filled. Latex balloons that have been properly filled should have a rounded appearance instead of a light bulb or pear shape. 

How do I fill a balloon with helium?
Every balloon has a small valve or opening at the “tail”. Slide this opening onto the nozzle of the helium tank until you have a tight fit. Make sure you hold the neck of the balloon firmly around the nozzle with one hand and press on the nozzle with your other hand to release the helium into your balloon.

How do I fill a balloon with air? 
You can use your lungs or a balloon specific air pump. When using an air pump, attach the opening of the balloon to the nozzle of the pump. Pull out the hand lever on your pump and start pumping. 

What else can I fill a balloon with?
Balloons can also be inflated with other gases, such as hydrogen and nitrous oxide. If a balloon is completely transparent, you can opt to fill your balloon with confetti and glitter.  

How do you tie a ribbon to a latex and foil balloon? 
For latex balloons, tie the ribbon between the knot and the end of the balloon. Do not tie the ribbon around the valve of the balloon or a leak may occur. To tie a foil balloon, tie a ribbon around the neck of the balloon, just below the opening. You can flip the balloon upside down so the tail faces you if that’s easier.

Are your balloons of helium quality? 
Yes. All of our balloons are made suitable for inflation with helium.

Why do helium balloons deflate more quickly than air-filled ones?
Helium balloons deflate quicker than balloons filled with air because the helium particles are smaller than the air particles; thus, they escape more easily from the balloons. In other words, the larger air particles stay longer inside the balloons than the smaller helium particles. 

Why don't my balloons float?
There are numerous reasons that cause a balloon not to float. Firstly, a balloon must be inflated with helium, making sure that the balloon is blown up to its full size. 

A common reason for a balloon not to float is when it is under inflated. Do not fill a balloon smaller than 9 inches with helium as they only float for a few hours. When the weight of the balloon exceeds the lift of the helium gas, the balloon will also not float. 

Why do balloons deflate?
Balloons are not perfectly air-tight and deflate over time. Air can slowly diffuse through the surface, or leak through the knot. This effect proceeds faster with helium inflated balloons.

How can you make a balloon float longer? 
First, be sure to tie a tight knot in the neck of the balloon. If you are attaching ribbons to the balloons, be sure to tie the ribbon below the knot.

You can use a gel called “Hi-Float,” which forms a coating inside latex balloons that reduces helium or air loss. It is similar to the glue on the back of postage stamps. This gel is non-toxic. Unfortunately, we do not currently sell this item.

Do I require ribbons and clips? 
Ribbons and clips are used for helium inflated balloons and sold separately. The balloon clip is fitted to the neck of the balloon. The ribbon attached is 1.2 metre long. The pre-cut ribbon and clips is sold as a unit and come in packs of 50 and are available in various colours. We also have helium tanks that includes a roll of ribbon. 

Do I require sticks and cups? 
Balloon sticks and cups are used for balloons inflated with air. The balloon cup fits on the neck of the balloon and the stick is inserted into the cup. Sticks and cups are an economical way of displaying your balloons effectively. We sell sticks and cups in packs of 50 suitable for all latex balloons, as well as 4 inch and 9 inch foil balloons. 

Can balloons be used outdoors?
If you consider using balloons for an outdoors event, we suggest using heavier weights.  However, we cannot guarantee the float time of balloons in unfavourable weather conditions.

Please be aware of the following: 

  • Store balloons out of light and away from heat to maintain their quality. 
  • Wind can cause balloons to tangle or pop when they are blown into a sharp object
  • Weighted down arrangements/objects are at risk of being dragged 
  • Direct sunlight can cause the colour to fade and ‘oxidise’
  • Heat may also cause helium in the balloon to expand and pop the balloon 
  • A foil balloon can appear deflated in cold air, but it will fill out when warmed up.
  • Leave them sealed in the packet until needed.

Disclaimer about releasing helium balloons

Koch & Co do not advise the release of foil balloons as they could have deadly effects on the environment and the wildlife. 
It is now illegal to release balloon in the wild in many Australian states. Please check the current rules and regulations with your local government. 
There are many alternatives to balloon release celebrations: 
  • Blowing bubbles
  • Plant trees and bulbs
  • Write in chalk
  • Light a candle
  • Scatter fresh flower petals